U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

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THE NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards is a principal focal point in the Federal Government

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Institute for Basic Standards. Applied Mathematics. Electricity. Metrology. Mechanics.

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‘Located at Boulder, Colorado, 80301. “Located at 5285 Port Royal Road, Springfield, Virginia. 22151.
UNITED STATES DEPARTMENT OF COMMERCE • John T. Connor, Secretary

NATIONAL BUREAU OF STANDARDS • A. V. ASTIN, Director

The Band Spectrum of

Carbon Monoxide

Paul H. Krupenie

Institute for Basic Standards

National Bureau of Standards

Washington, D.C.

NSRDS-NBS 5

National Standard Reference Data Series

National Bureau of Standards—

(Category 3—Atomic and Molecular Properties)

Issued July 8, 1966

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C., 20402 - Price 70 cents
NATIONAL BUREAU OF STANDARDS

JUN 9 1970

QC (do

,0615

no- ^

\ cjbb

Library of Congress Catalog Card Number: 65-62765
Foreword

The National Standard Reference Data System is a government-wide effort to give to the

technical community of the United States optimum access to the quantitative data of physical

science, critically evaluated and compiled for convenience. This program was established in

1963 by the President’s Office of Science and Technology, acting upon the recommendation of

the Federal Council for Science and Technology. The National Bureau of Standards has been

assigned responsibility for administering the effort. The general objective of the System is to

coordinate and integrate existing data evaluation and compilation activities into a systematic,

comprehensive program, supplementing and expanding technical coverage when necessary,

establishing and maintaining standards for the output of the participating groups, and providing

mechanisms for the dissemination of the output as required.

The NSRDS is conducted as a decentralized operation of nation-wide scope with central

coordination by NBS. It comprises a complex of data centers and other activities, carried on

in government agencies, academic institutions, and nongovernmental laboratories. The

independent operational status of existing critical data projects is maintained and encouraged.

Data centers that are components of the NSRDS produce compilations of critically evaluated

data, critical reviews of the state of quantitative knowledge in specialized areas, and

computations of useful functions derived from standard reference data.

For operational purposes, NSRDS compilation activities are organized into seven categories

as listed below. The data publications of the NSRDS, which may consist of monographs,

looseleaf sheets, computer tapes, or any other useful product, will be classified as belonging to one or another of these categories. An additional “General” category of NSRDS publications

will include reports on detailed classification schemes, lists of compilations considered to be

Standard Reference Data, status reports, and similar material. Thus, NSRDS publications

will appear in the following eight categories:

Category

12

3

4

5

6

7

8

Title

General

Nuclear Properties

Atomic and Molecular Properties

Solid State Properties

Thermodynamic and Transport Properties

Chemical Kinetics

Colloid and Surface Properties

Mechanical Properties of Materials

The present compilation is in category 3 of the above list. It constitutes the fifth

publication in a new NBS series known as the National Standard Reference Data Series.

A. V. Astin, Director.

Ill
Contents

Page

1. Introduction 1 2. Electronic structure of CO and CO+ 2

2.1 Electronic structure 2

2.2 Numerical calculations 4

a. Semiempirical 4

b. Single configuration 4

c. Configuration interaction 4

2.3 Rydberg states and Rydberg series 5

3. Electronic spectrum of CO and CO+ 5

3.1 A1 !! — Xx 2+ Fourth Positive system (2800-

1140 A) R... 6

3.2 Bx 2+ —

A

X II Angstrom system (6620-4120

A) V 8

3.3 Cx 2+ —

A

x n Herzberg system (5710-3680

A) V 9 3.4 Hopfield-Birge systems (1810-950 A) 10

a. Bx 2+, 02+ Ex n, F(x 2+), G(x n), and

5

32+-Xx 2+ 10

b. a' 3 2+-Xx 2+ (1810-1280 A) R 10

3.5 a

3 n —

X

x 2+ Cameron system (5800-1770

A) R 11

3.6 5

3 2+ — a

3 n Third Positive system (3820-

2660 A) V __ 12

3.7 c

3 2+—

a

3n 3A system (2710-2300 A) V_ 13

3.8 o

/32+ —

a

3n Asundi system (8590-3900 A)

R 14

3.9 d

3A, —

a

3n Triplet system (7500-3770 A)

R - 15

3.10 e

3 2~ —

X

x 2+ transition (1540-1240 A) R_. 16

3.11 Cx 2+ —a' 32+ Knauss system (3250-2930

A) V - 17

3.12 Kaplan bands (2750-2520 A) 17

3.13 d

3Ai— Xx 2+ transition (1620-1230 A) R__ 17

3.14 e

3 2

- —

a

3n Herman system (5430-4270 A)

R 17

3.15 E0

X 2+—

X

x 2+, 1 n — X1 2+, and several unidentified transitions in the vacuum UV

region (1180-930 A) _ 17

3.16 /

32+ —

o

3n transition (2980-2670 A) R 18

3.17 I

1 2--X1 2+ transition (1520-1460 A) R__ 18

3.18 Unidentified bands 19

3.19 P, Q, R, S, T —

X

x 2+ Tanaka systems

(800-630 A) R 19

3.20 Rydberg series (940-630 A) 19

3.21 B2 2+ —

X

2 2+ First Negative system of CO+ (3150-1800 A) R 20

3.22 A2 IU—

X

2 2+ Comet Tail system of CO+

(7200-3080 A) R 21

3.23 B2 2+ — A2 IU Baldet-Johnson intercombination system of CO+ (4240-3310 A) V_ 22

4. Perturbations 22

4.1 A1 n state 22

a. v=0 22

b. v=l 23

c. v=2 24

d. v=3 24

e. »=4 24

f. v=5 24

g. i>=6 24

Page

h. v=7 24

i. v=S 25

j. v = 9 25

k. t> — 10 25

l. v = 11 25 m. v=12 25

n. v=\2> 25

4.2 Ex n state 25

4.3 a

3 n state 25

4.4 d

3 A,- state 26

4.5 /

3 2+ state 26

4.6 b

3 2+ state 26

4.7 A2 n,- state of CO+ 26

a. v—5 26

b. ?; = 10 27

5. Dissociation energies, pre dissociations, and

convergence limits 27

5.1 Dissociation energy of CO 27

5.2 Predissociations and convergence limits. _ 28

a. Pre dissociation of the Bx 2+ state 28

b. Predissociation of the fe3 2+ state 28

c. Pre dissociation of the Cx 2+ state 29

d. Suspected predissocation of the ^2+

state 29

e. Convergence limit of the a' 32+ state 29

f. Convergence limit of the F(x 2+) state __ 30

5.3 Dissociation energy of CO+, ionization

potentials and Rydberg series 30

5.4 Dissociation energy of C02+ 31

6. The vibration-rotation spectrum of CO 31

6.1 Ay=l sequence 31

6.2 Overtone sequence and other overtone

bands 31

7. Rotational spectrum of CO (microwave and

far infrared) 32

7.1 Rotational transitions in CO 32

7.2 Stark effect 32

7.3 Zeeman effect 32

7.4 Quadrupole hyperfine structure 33

8. Raman, Stark, and Zeeman effects in electronic

spectra of CO and CO+ 33

8.1 Raman effect 33

8.2 Stark effect 33

8.3 Zeeman effect 33

9. Molecular energy levels and potential energy

curves 34

10.

Transition probabilities and lifetimes (electronic

spectra) 35

10.1 Ax n —

X

x 2+ Fourth Positive system 35

10.2 Bx 2+ —

A

x n Angstrom system 35

10.3 Cx 2+ —

A

X II Herzberg system 35

10.4 5

3 2+ —

a

3 n Third Positive system 35

10.5 o' 3 2+ —a

3 n Asundi system 36

10.6 a

3 n —

X

x 2+ Cameron system 36

10.7 5

3 2+ —

X

x 2+ Hopfield-Birge system 36

10.8 a' 3 2+ —

X

x 2+ Hopfield-Birge system 36

10.9 d

3A<—

a

3 n Triplet system 36

10.10 A2 n, —

X

2 2+ (CO+) Comet Tail system. 36

10.11 B2 2+—

X

2 2+ (CO+) First Negative sys- tem 37

IV
Contents—Continued

Page

10.12 B2 2+ — A2 n, (CO+

) Baldet-Johnson sys- tem 37

10.13 Ionization of CO 37

10.14 Miscellaneous 37

11.

Summary and conclusion 37

Page

12. Tables and figures 38a

13. References 78

Appendix A—notation and terminology 85

Appendix B—physical constants and conversion

factors 87

Tables

1. Molecular constants, electron configurations,

and dissociation products for the electronic states

of CO and CO+. Supplement: Rydberg states. 38a

2. Electron configurations for states of CO and

CO+ 39

3. Band heads of the A1 !! — Fourth Positive

system (R) 40

(a) Emission 40

(b) Absorption 41

4. Deslandres table for the band origins of the

A1 H-X1 2+ Fourth Positive system 42

5. Band heads and origins of the A! n — X! 2+ Fourth

Positive system of C13 016 (R) 43

(a) Emission 43

(b) Absorption 43

6. Band heads and origins of the B! 2+—> A1 n

Angstrom system (V) 43

7. Band heads and origins of the B1 ^—A1 !! sys- tem of C13016 (V) 43

8. Band heads and origins of the Cx 2+— Iierzberg system (V) 43

9. Band heads of the Hopfield-Birge systems 44

(a) B1 2+ *->-X1 2+ 44

(b) C1 2+ -<-»-X1 2+ 44

(c) E1 n^X1 2+ 44

(d) F(1 2+)^X1 2+ 44

(e) G(1 n)^-X1 2+ 44

(f) fe 3 2+ —

X

! 2+ 44

10. Band heads and origins of the a' 3 2+<—

X

] 2+

Hopfield-Birge system (R) 44

11. Band heads of the a

3 n — X1 2+ Cameron system

(R) 45

(a) Emission 45

(b) Absorption 45

12. Band origins of the a

3 IT — X! 2+ Cameron system. 45

13. Band heads of the 6

3 2+—>a 3 n Third Positive

system (V) 46

14. Band heads of the c

3 2+ —>a3 n 3A system (V)__ 46

15. Band heads of the a

/32+ —>a3 n Asundi system

(R) 47

16. Band heads of the d3Ai—.»a3 n Triplet system

(R) 49

(a) Identified bands 49

(b) Unassigned bands 50

17. Band origins of the d3Ai—a3 n Triplet system __ 50

18. Band heads and origins of the e

32

_4~X1 2+ sys- tem (R) 50

19. Band heads of the C‘2+ —>a' 3 2+ Ivnauss sys- tem (V) 50

20. Band heads of the Kaplan system (R) 50

21. Band heads of the d

3A,<— X’2+ system (R) 51

22. Band heads of the e

3 2~—>a3 n Herman system

(R) 51

23. Band heads of the Eo^-1"—>X'2+ system (R) 51

24. Band heads of the 1 II—>X1 2+ system (R) 51

25. Band heads of the

/

3 2+ —>a3 n system (R) 51

26. Band heads of the Tanaka systems (absorption) 52

(a) P^-X! 2+ 52

(b) Q"-Xj 2+ 52

(c) R<— XJ 2+ 52

(d) S<—

X

x 2+ 52

(e) T<— X*2+ 52

27. B2 2+ (C0+

)

<—X1 2+ “/3” Rydberg series 52

28. A2ni (CO+)<-X1 2+ “a” Rydberg series 53

29. X2 2+(CO+)«—

X

3 2+ Rydberg series 53

30. Band heads of the B2 2+—>X2 2+ First Negative

system of CO+ (R) 53

31. Band origins of the B2 2+ —

X

2 2+ First Negative

system of CO+ 54

32. Band heads of the A2 II;—>X2 2+ Comet Tail

system of CO+ (R) 54

33. Band origins of the A2n,—

X

2 2+ Comet Tail

system of CO+ 55

34. Band heads of the B2 2+ —>A2 IU Baldet-Johnson

system of CO+ (V) 55

35. Miscellaneous unclassified bands 55

(a) Band heads observed together with the

A1 !! — XJ 2+ Fourth Positive system (Emission) 55

(b) Band heads observed in absorption 55

(c) Band heads observed with the a' 32+ —>a3 n

Asundi system 56

(d) Band heads observed in emission by

Tschulanovsky and Gassilevitch 56

(e) Triplet bands observed in emission 56

(f) Unclassified absorption maxima 56

(g) Unclassified absorption bands 57

(h) Emission and absorption bands of Anand__ 57

(i) Band heads observed together with the

A2 n,—>X2 2+ Comet Tail system of CO+ 57

(j) Band heads observed with the B2 2+ —> A2 n, system of CO+ 57

36. Rotational constants for the X‘2* state 58

37. Rotational constants for the A'n state 58

3S. Rotational constants for the B'2+ state 58

V
Tables—Continued

39. Rotational constants for the 0*2+ state.

40. Rotational constants for the E1 !! state..

41. Rotational constants for the a' 32+ state42. Rotational constants for the a

3 n state. _ 43. Rotational constants for the b

3 2+ state.

44. Rotational constants for the c

3 2+ state.

_

45. Rotational constants for the d

3A; state..

46. Rotational constants for the e

3 2~ state..

47. Rotational constants for the Eo1 2+ state

48. Rotational constants for the 1 n state

49. Rotational constants for the /

3 2+ state..

50. Rotational

CO+

constants for the X2 2+ state of

51. Rotational

CO+

constants for the a2 ir state of

52. Rotational

CO+

constants for the B2 2+ state of

53. Doublet splitting constants for states of CO+._

54. Perturbations of the electronic states of CO

and CO+

(a) A1 !! state

(b) E1 !! state

(c) o

3 II state

(d) d3Ai state

(e) f

3 2+ state

(f) b

3 2+ state

(g) A2 n, state of CO+

55. Observed predissociations in C12 016 and C13 016 . 56. Vibration-rotation bands of CO in the infrared

region

57. Dipole moments for states of CO and CO+

58. Rotational frequencies, rotational constants,

and magnetic moments of carbon monoxide

59. Hyperfine structure

60. (a) Franck-Condon factors for the A1 !! —

X

! 2 + Fourth Positive system

(b) r-centroids (A) for the A1 !! — X! 2+ Fourth

Positive system

61. Franck-Condon factors, band strengths, r1. Potential energy curves for CO and CO+

Pag*

centroids, and I OT for the B1 2+ —A1 n Angstrom

system 66

Franck-Condon factors for the C^"1"— A1 !! Herzberg system 66

Franck-Condon factors, band strengths, r- centroids, and 1^ for the b

3 2+ — a3 n Third Positive system 66

Franck-Condon factors for the a' 32+ —

a

3n

Asundi system 66

Franck-Condon factors for the a

3 n —

X

! 2+ Cameron system 67

Franck-Condon factors for the b

3 2+ — X^4- Hopfield-Birge system 67

Franck-Condon factors for the a' 32+— X^4

" Hopfield-Birge system 67

Franck-Condon factors, r-centroids, and 1^ for the d3Ai— a

3 n Triplet system 68

(a) Franck-Condon factors, r-centroids, and

wavelengths for the A2 n, —

X

2 2+ Comet

Tail system of CO+ 69

(b) Smoothed band strengths and I ro for the

A2 n,-— X22+ Comet Tail system of CO+ 70

Franck-Condon factors, r-centroids, and wavelengths for the B2 2

+ —

X

2 2+ First Negative

system of CO+ 71 Franck-Condon factors, r-centroids, and wavelengths for the B2 2+—

A

2 !!; Baldet-Johnson

system of CO+ 72

Franck-Condon factors for ionizing transitions. 73

(a) Lifetimes, Einstein coefficients, and oscil- lator strengths 74

(b) Einstein coefficients, absolute band

strengths, and band oscillator strengths

for the A2 !!, —

X

2 2+ Comet Tail system

of CO+ 74

(c) Absolute /-values for the A1 ]!—

X

1 2+ Fourth Positive system 74

Potential energy of the electronic states of CO

and CO+ 75

Energy level diagram for CO and CO+ 77

Page

58

59

59 62. 59

59 63. 59

59

59 64. 59

59 65. 59

66. 60

67. 60

68. 60

60 69.

60

60

62

62 70. 62

62

62 71. 63

63

72. 64 73. 64

64

65

65

65 74.

Figures

77 2.

VI
The Band Spectrum of Carbon Monoxide*

Paul H. Krupenie

This is an exhaustive review of the literature and a critical compilation of the observed

and predicted spectroscopic data on CO, C0+

, and C02+ in the gas phase.

Key Words: Carbon monoxide, spectrum, review.

1. Introduction

There exists no unified compilation of spectroscopic data for diatomic molecules. The standard

references in use, now incomplete and out of date, are the tables of molecular constants in Herzberg’s

book [99]

1 and the more extensive compilations

by Rosen et al., [213] which include band positions

and perturbations. Rapid accumulation of new

data has made apparent the need for a current

critical review and more extensive compilation.

This need has been partially met by recent tabulations of band head wavelengths by Pearse and

Gaydon [187], and the compilation of these and

other data for a select group of diatomic molecules

of astrophysical interest by Wallace [266]. The

only recent review known to the author which is devoted to a single molecule is that of Lofthus

[153], “The Molecular Spectrum of Nitrogen.

The present work, first in a series on diatomic

molecules,2 follows the approach of Lofthus and

is devoted to a single molecule. This report

includes a comprehensive review of the literature on the spectrum of CO, CO+

, and C02+ in the gas

phase,3 and a compilation of critically evaluated

numerical data on band positions, molecular constants, energy levels, potential energy curves, and

other molecular properties derived from the

spectrum. Estimates of reliability are given

where possible.

Papers from which the tabulated data have been

extracted are discussed in the text of this report.

Early data of presumably low precision have been

included in the tabulations only where better or more recent data are not available. The refer- ences cited constitute a critical bibliography rather

than an exhaustive one. The author will be

•Work supported in part by the National Aeronautics and Space Adminstration.

1 Figures in brackets indicate the literature references on page 78.

1 The second report in this series will be devoted to Oj.

3 Information on C0J* is obtained from electron impact.

indebted to readers who bring to his attention

significant references not included in the bibliography.

No spectrograms are included in the report

(but see table 1 for references with reproductions

of spectra). However, R. W. Nicholls of the

Department of Physics, York University Toronto,

Ontario, Canada has forthcoming identification

atlases for various band systems including several

for carbon monoxide.

Discussions of infrared intensities, absorption

coefficients, and line shapes and widths are omitted

here ; literature on these topics can be traced from

references in the recent paper by Benedict et al.,

[18].

Carbon monoxide is an important molecule for

the following reasons: (1) It is a product of combustion of organic molecules and plays an important role in the reactions of flames; (2) it appears

as an impurity in many systems and its spectrum

is readily excited, especially the strong A-X

Fourth Positive system in the UV ; (3) it is a constituent of the solar chromosphere, stellar at- mospheres, and comet tails [CO+

], [the increase in

rocket and satellite observations will enhance its

importance]; (4) because it is a light molecule its

electronic structure is amenable to theoretical

analysis; (5) it is isoelectronic with N2 which is important as the primary constituent in the earth’s

atmosphere; and (6) it can be obtained in pure

form and is readily handled in the laboratory.

The spectrum of CO is dominated by three

prominent band systems: A'n —

X

1 ^

Fourth

Positive system (2800-1140 A), 6

3 2

+ —a

3 n Third

Positive system (3800-2600 A), and Bl w

+ —Al n

Angstrom system (6600-4100 A). The A-X

system is the most pronounced and extensive,

with more than 150 bands being observed. For

CO+ the A2 n<—X2S

+ Comet Tail system (7200

3080 A) is the strongest. This system may be
important in radiative heating of hypersonic

vehicles at escape velocity or in the atmospheric

fringe of the planet Venus (which contains C02). Study of the carbon monoxide spectrum in the

visible region originated with the work of Angstrom and Thalen in 1875. The earliest band head

measurements in the UV were made by Deslandres

in 1888, and by Lyman shortly after the turn of

this century. All of the early observations on CO have been cataloged in volumes V and VII

of Kayser’s Handbuch der Spektroscopie [127], but

they can most easily be traced from an early

review on the band spectra of CO by Birge [23].

The modern study of the spectrum of carbon

monoxide began in 1926. In that year, Birge

[22, 23] obtained the vibrational analysis of the

A1 !!—

X

1 ^

Fourth Positive system, which, to- gether with the correlation of emission and absorption measurements, enabled him to draw an energy

level diagram for the observed electronic states. The impetus provided by the development of the

quantum theory together with improved spectroscopic techniques resulted in extensive work in

the 1930’s on rotational analyses, and study of

perturbations and predissociations. In the early

1940’s, there appeared the first studies of Rydberg

series, followed a decade later by the beginning of

precise infrared vibration-rotation spectral measure- ments and microwave studies. Controversy of

30 years standing over the value of the dissociation

energy of CO appears to have been convincingly

settled by Douglas and Mpller’s re-examination

[56] and review of the suspected predissociations

of the A1 !! state. The mid-1950’s ushered in renewed interest in

forbidden transitions and new states. Two bands

previously thought to originate from high vibrational levels of the a

/3 2

+ state (though questioned

by Garg [68], Herzberg [99], and Gaydon [69]),

have been indirectly found to originate from the

/

3 S

+ state by more recent work of Herzberg and

Hugo [101]. The F2 ~ state, previously known

only from its perturbations of the A1 ]! state,

has been observed in forbidden transition to the

X! 2

+ state. Complete details are not yet

available.

Current effort is still centered more on the

determination of energy levels (i.e., precise

measurements of line positions) rather than on

the more difficult intensity measurements.

2. Electronic Structure of CO and CO+

The early work of Mulliken [167, 168], largely

intuitive and semiempirical, has laid the foundation for our understanding of the electronic

structure and spectroscopic properties of carbon

monoxide. Recent numerical calculations qualitatively account for a number of these features,

though quantitative predictions are generally less

reliable. The order of bound electronic states

lying below 11 eV has been correctly predicted,

but not their numerical term values. Energies

of some unobserved electronic states have been

estimated. Calculated ionization potentials agree

fairly well with experimental values. HartreeFock calculations question the experimentally

determined polarity of the dipole moment. Theoretical prediction of the identity of the E state

as HI has been confirmed experimentally. Poor

values are obtained for the ground state binding

energy and potential energy curves of low Ring

states. This section reviews what is known about the

electronic structure of CO and CO+ and briefly

summarizes the results of numerical calculations.

Elements of molecular orbital theory and definitions of terms used are given elsewhere [200,

250, 172]. Abbreviations used include: IP, ionization potential; MO, molecular orbital; LCAO,

linear combination of atomic orbitals; Cl, configuration interaction; SCF, self-consistent field; a.u., atomic units (=27.210 eV).

2.1. Electronic Structure

The relative order of the molecular orbitals for

CO is as follows [46, 171, 168, 109, 173]:

(a) crls < (7*lS <C[ cr2s < a*2s <C 7T y2p=Trz2p V b<Na. < Tr'Jlp—Tr'^p < <r*2 p

(b) K K Za ya Wtt Xa vt Ua

(c) 1 a 2a 3(7 4(7 1 7

r

5(7 2 7T 6(7

inner inner b. a.b. b. a.b. a.b. a.b.

2
Orbital designation (a) specifies the atomic origin

of the MO’s; designations (b) and (c) in current

use, do not. The bonding character of the orbitals

is specified above as: bonding, antibonding, or nonbonding, la- and 2 a orbitals virtually retain

their purely atomic character and are often called

K or inner orbitals. 3o- is primarily 0(2s); 4ois a mixture of C(2s) and 0(2p), though the actual

ratio is a function of r. The 5a- (slightly a.b.)

and 1 7r orbitals have similar energies and can

be expected to have their order reversed at some

value of r. Isoelectronic molecules have similar

MO’s and roughly similar sequence of MO’s, as

is the case for CO and N2 up to about 11 eV.

At higher energies this similar order is destroyed.

The assignment of the electronic structure and

dissociation products of a number of states of

CO and CO+ has been given by Mulliken [168].

The ground state configuration is X1 S

+ (lo-) 2 (2o-)

2 (3o-)2 (4a-)2 (l7r)

4 (5a-)

2

.

An examination of the ionization process from

successively deeper lying orbitals shows why

only three states are known for CO+. This is summarized below:

Electron

ionized

Ionic

state

I.P.(eV) *

5 a x2 z+ 14. 013

1 7T A2 IIi 16. 544

4a B2 S+ 19. 671

3a 2^+ 41 ± 3

The ionization of the 3a- electron lias not been

observed. There is some evidence for a state

of CO+ at 25.6 eV (±0.5 eV) from electron impact

[151] and photoionization [270] studies. (This

has been called the C

2 2+ state, but it does not

correspond to the removal of a 3o- electron.)

Codling [42] has recently observed structure in

the 500 A region which appears to include a Rydberg series whose convergence limit lies above

20 eV. By analogy with Nj the electron configuration of this limiting state may result from

a two-electron excitation. States of C02+

, detected at 41.8 eV and 45.7 eV in electron impact

4 The three lowest IP have been determined experimentally from Rydberg

series limits and electronic spectra of CO+ (sec. 5.3). Only a calculated value

is available for the IP of the 3o electron [109, 173], Long ago Mulliken [109] estimated this quantity as 32 eV.

experiments [55, 263], have not been observed

spectroscopically. Hurley and Maslen [111] have

calculated the lower state energy to be 41.17 eV.

Ground state atoms C(3 P)±0(3P) give rise to

18 possible electronic states of CO (table 2).

Only eight of these have been observed: Xx 2

+

, a

3 n, d3 A{ , e

3 2~, a'3 2

+

, A! IT, and P2~; all the

others are probably weakly bound or repulsive,

though the *A state might be slightly stable [167].

However, a (

1 II

1 II) or (WIT) perturbation at low

J in A1 ]!, v=0, 1 at about 8 eV can only come

from a stable state [44, 71, 216]. Therefore, if real, these perturbations would most likely arise

from one of the unobserved states. A possible

(WA) perturbation of the d state indicates the

presence of a

1 A state at about the same energy

[137]. By analogy with N2 such a state would

lie at about 9 eV.

Kaplan [126] has reported a state of unknown

type at about 4.8 eV above X. The reality of a

state of CO at this energy is, however, highly

questionable [168, 99, 187].

For the higher energy excited molecular states

beginning with C

3 2

+

, at least one excited atom is required in the dissociation products, since the

electronic energy alone exceeds the heat of dissociation into ground state atoms. In the case

of singlet states of CO not formed from ground

state atoms, both atoms must be excited. Table

1 is a summary of the known molecular constants

and includes the assigned electron configuration

and dissociation products where possible, for the

observed electronic states. Table 2 gives the

lowest lying configurations and possible molecular

states, with the observed states indicated.

Mulliken [171] has recently compared the observed lower excited states of the 7t

3 7t configuration

with those predicted for CO. The d-state of

CO was proposed to be a case (b) 7t

3 7t3 A in disagreement with the earlier experimentally determined

assigmuent as d

3 n4

. Carroll [40] experimentally

confirmed Mulliken’s assignment of the d state

as

3 A, but definitely established it to be inverted.

A 7t

3

7t configuration gives rise to a

3 A r state in the

usual approximation. A theoretical interpretation of the anomalous multiplet splitting in the

d

3 A term has been given by Ivovacs [137].

The xV states are

! 2+, F2~, X A, a'3 2+, e

3 2~, and

d

3A t

. Recent information [100, 23Sa] indicates

the I state lies at about 66000 cm-1

, and the e state at about 63000 cm-1

. The ‘A state and

1 2

+ remain unobserved.

794-90S—G6 2 3
2.2. Numerical Calculations

a. Semiempirical

Semiempirical studies have provided a qualitative understanding of several properties of the

carbon monoxide molecule. The triple bond for

the ground state has been accounted for by Sahni

[217], Mulliken [170], and Linnett [152]. (See

also ref. [154].) Moffitt [164] has correlated

the decrease in bond length for states of CO and

CO+ with increase in 7r-bond order. Sahni [217],

with neglect of Is electrons and the use of many

approximate integrals, has derived individual and

total orbital electron densities which are shown in

contour diagrams. The lowest ionization of CO,

that is, removal of an almost nonbonding electron

from the 5a orbital, has been shown loosely

equivalent to removal of an electron from the

carbon atom [217, 170, 152]. Indeed, the dissociation products of the ground state of CO+ are C++0.

b. Single Configuration

Several calculations for CO have been made

using single configuration LCAO-MO-SCF wave

functions. Ground state energies have been calculated by Ransil [199, 200] and Hurley [110] usingfunctions constructed from minimal basis sets. Merryman et al. [159], and Brion and Moser [29]

have calculated excitation energies for a number

of states from similar functions. For states lying

above 9 eV the calculated energies are too high.

To describe such states it is necessary to include

more than one configuration or to introduce atomic

orbitals of higher quantum number. LefebvreBrion et al. [146], have compared the vertical excitation energies calculated from SCF functions

built from extended basis sets. Calculated values

agree fairly well with experiment, even for states

lying above 11 eV.

The most accurate wave functions for the ground

state of CO have recently been reported by Wahl

and Huo [265] and Huo [109]. Huo has calculated

single determinantal SCF wave functions from two

extended basis sets, including one built by extending the basis set necessary for obtaining accurate

Hartree-Fock functions for the atoms. The calculated value of the total molecular energy is — 112.7877 a.u. This result was obtained from a minimal basis set supplemented by ISq, Is', 2s', 2^?7r0

,, 2pTc , 2pa0 , 2pa'c , 3da^, 3 dac, Sdn^,

3dir c , 2pTr0 , 4/7r c , 3 s 0 , and 3s c

. Expectation values

of several one-electron operators are given as well as contour diagrams for orbital and total

charge densities [109(b)].

Expectation values of a number of one-electron

operators were calculated, including the dipole

moment whose polarity was determined as C+0~,

in disagreement with the reverse assignment given

by Rosenblum, Nethercot, and Townes [215] from

microwave experiments. Huo [109] and Nesbet

[173] have independently concluded that more

accurate SCF functions should not change the

sign of the dipole moment, and that the polarity

should be considered undetermined.

Nesbet [173] has calculated SCF functions for

the ground state of CO using a double exponential

basis set with optimized exponents for each

occupied atomic orbital. This basis set appreciably lowers the total energy but makes only a small change in the binding energy from that

using a smaller basis set. The addition of da and

dir orbitals makes only a small change in the total

energy but makes a larger improvement in the

binding energy.

c. Configuration Interaction

Configuration interaction has been used to

calculate the correlation energy [experimental total

energy—Hartree-Fock energy]. Combined use of

extended basis sets and Cl results in improved

values of excited state energies and gives lower

calculated total energies. Lefebvre-Brion et al. [144], have found that use of a basis set w-hich

includes functions from the M shell (3s and 3p)

with Slater exponents improves the calculated

vertical excitation energies more than does

doubling the number of L shell functions. By

using orbitals constructed from a minimal basis

set and including Cl they have also [145] calculated

potential energy curves for a number of states. These include repulsive 3 n and 1 n states which lie at 11.5 and 12 eV, respectively. The latter value

agrees with the vertical excitation energy of the

F state and suggests that the F state is not 'IT. [See also ref. 146.] The fragmentary data in

section 5 suggest that the F state may be triplet.

Lefebvre-Brion [147] predicts the state to be 1 2

+

(table 1).

Fraga and Ransil [66] have calculated the

molecular energy and dipole moment for the

ground state of CO using a limited Cl with minimal

SCF wave functions. Even with 14 configurations

(having the same symmetry as the ground state)

4
Eca)0 —

E

ob9 is about 27 eV. These results indicate

the need [66] to include MO’s with different X

values and atomic orbitals of different l values

from those utilized in the ground state.

2.3. Rydberg States and Rydberg Series

The observed Rydberg states in CO (table 1 supplement) are most probably singlet, and

either IT or 2

+

, since they have all been detected

in absorption series. There may exist others

which do not combine with the ground state and

could be observed in emission, but to date none

have been reported. The electronic structure of

the states considered is given below:

Configu- Possible Rydberg states Convergence

ration limit [CO+]

obiter) I 2+, 3 S+

X, B

o-(R-7t) J n, 3 n

7r 3 (R<r) ! n, 3 ir A

7r

3 (Rir) 1 2+, 1 2~, ! A, 32+, 3 2", 3A

For the most likely Rydberg orbitals npx or npa, the most likely states are II or 2. Huber

[106] believes that the states converging to the

X and B states of CO+ are x 2

+ and the a states

converging to A2 IT are x n, all having Rydberg

orbitals npa. Tanaka [254] has speculated that

the sharp /3 series is composed of 1 2

+ states and

the diffuse /? states are 1 II. With present knowledge it is not possible to specify uniquely their

symmetry types.

Rydberg states with orbital n dissociate into

atoms at least one of which is configurationally

excited (i.e., having principal quantum number

greater than in its ground state, (n— 1)>3).

Huber [106] suggests that the dissociation products

of series converging to states X and A are C(n— l)s(3 P°) +0(3 P), and states converging to B

have products C(n— Os^P^+OfffD).

Lefebvre-Brion, Moser, and Nesbet [147] have

recently calculated the energies of Rydberg

levels of CO which are of symmetry type 1,3 2

+ and 1 ' 3 n and lie below the first ionization potential.

The calculated energies fall within 0.2 eV of the

observed values for the B

x 2+

, 0*2+, 6

3 2

+

, and

c

3 2

+ states which probably belong to Rydberg

series converging to the ground state of CO+. The configuration interaction functions used were built from LCAO-MO-SCF orbitals used

previously [146, 148] for calculations on the

ground state of CO, but with extended basis sets. The deviations between these calculated energies and experiment indicate that the E state is

1 n, and the F state may be 1 2

+. The E state

assignment has been confirmed experimentally by

Tilford et al. [257]; the tentative assignment of

the F state as

: 2

+ is untested. (See sec. 5.2f

and table 1, footnote F(1 2

+

).) No 3 IT RtMberg

levels of CO have been observed to date. Codling

[42] has recently observed Rydberg series con- verging to what may be a new state of CO+ above

20 eV, but the symmetry and type of Rydberg

levels have not been identified as yet.

3. Electronic Spectrum of CO and CO+

The spectral region 8600-600 A includes all the

presently known electronic transitions of CO and

CO+. Intense systems span most of the region

between 7500-1100 A. From 3800 A to longer

wavelengths are found the B-A Angstrom bands

and the d-a Triplet system, the latter system

composed of many bands, only four of which have

had rotational analysis. Between 7200-3000 A is found the A-X Comet Tail system of CO+

, the

most prominent system of the ion. From 3800-

2600 A is the b-a Third Positive system which is most important because of the most violent perturbations and predissociation of the b state. The

A-X Fourth Positive system dominates the region

between 2800-1140 A, though the shorter waveo length bands are rather weak. Below 1200 A are found, in general, weak sj^stems, incompletely

studied, for which no rotational analysis is available. In total 29 transitions are found among the

23 known states of CO. Three states of CO"

partake in three observed transitions. Details

of the observed transitions are discussed below,

including the determination of vibrational and

rotational constants, multiplet splitting, and

coupling cases of the electronic states. The

critically evaluated data pertaining to these

transitions have been tabulated in section 12.

5
3.1. A1 !!—

X

X S+ Fourth Positive System

(2800-1140 A) R

The A^-X1 ^

Fourth Positive system, originally attributed to carbon, is the most prominent

system of carbon monoxide in the ultraviolet and

vacuum TJV regions. The single-headed reddegraded bands of this allowed transition are about

a thousand times stronger than those due to

forbidden transitions which they overlap. Wavelengths of more than 150 emission bands which

have been observed in the region 2800-1280 A are assembled in table 3a. Included among these are

early measurements by Lyman and Deslandres

of 30 band heads whose vibrational assignments

are due to Birge [23], and which have not been

reported by anyone else. Band origins for this

system are given in table 4. Rotational constants

for the X and A states are given in tables 36 and

37, respectively. Positions of a number of unidentified bands have been assembled in table 35a.

These have been observed together with the A-X

system and possibly belong to it. Attention is focused on the A-X system by the

numerous perturbations of the A1 II state, a

detailed discussion of which is given in section 4.1.

The recently observed PIT state was first identified

from its interaction with the A state. Several

predissociations of the A state have been reported

which have led to conflicting values of the dissociation energy of CO. Re-examination of these

by Douglas and Mpller [56] has shown that none

of them are real.

The work before 1926, including the earliest

band head measurements by Deslandres and

Lyman, was discussed and analyzed for the first

time by Birge [23]. All observations prior to

that date were in emission, except for Leifson’s

[149] observation of the strong v"=0 progression

(with v' =0 to 11) in absorption. The vibrational

analysis of this system [23, 22] and the correlation

of Lyman’s emission bands with the absorption

bands of Leifson showed that they were due to

neutral CO. Thus an energy level diagram could

be drawn with the lower state of this system

established as the ground state. Estey [60] remeasured part of the A-X system

in the region 2800-1970 A, and observed 16 new

bands which involve high vibrational levels of

the ground state. His source was a low pressure

discharge, viewed with a quartz spectrograph

having dispersion 3.91 A/mm-1.21 A/mm. Each

band clearly shows a single P, Q, and R branch

as is expected for a transition. Less

extensive band head measurements by Wolter

[277] agree with those of Estey to within 0.1 A.

Headrick and Fox [90] measured bands in the

region 2170-1280 A, using a 1-m focal length

vacuum spectrograph. Several new bands were

reported, mostly at shorter wavelength. The

source was a low voltage arc in CO at 0.5 mm

pressure with a trace of hydrogen. Wavelengths

obtained from the use of two different standards

agreed to within 0.2 A, and are close to the values

of Estey [60] where they overlap near 2000 A.

Dispersion was 17.4 A/mm. Intensities, originally

given as densitometer readings, have been con- verted in this report to a scale with the maximum

reading taken as 10. In table 3a, for the bands

above 2000 A, the intensities are those given

primarily by Estey [60]; below 2000 A, the intensities are those of Headrick and Fox [90]. Several

strong unidentified bands at short wavelengths

have been included in table 35a.

Read [209] has given the vibrational analysis of

65 heads, observed in a hollow cathode discharge

in flowing C02 , and viewed with a 2-m focal

length vacuum spectrograph with dispersion of

4.2 A/mm. In addition, he resolved the rotational

structure for 12 bands, but details only of the 1-1

and 4-10 bands have been published [209b].

This was the first rotational analysis of bands

involving the ground state of CO. A-doubling

was found to be negligible, as had been determined

from earlier studies of the B! 2—

A

1 !! Angstrom

bands.

A formula was obtained which fit the newly

reported band heads as well as those of Estey

at longer wavelength:

crH(v' —v") =64756.3 + (1497.49v' — 17.1 S41z/2) — (2155.61yr/ — 13.2S43*/'2 +0.012z/'3) —0.0804 v'v".

The derived vibrational constants are ver}T close

to the best values listed in table 1. The papers of Estey [60], Headrick and Fox

[90], and Read [209] include almost all of the

emission band head measurements of the A-X

system. Shortly after then- publication there

began to appear extensive rotational analyses,

mostly by Schmid and Gero.

In a Geissler discharge in C02 , Gero [73] observed a series of bands in the region 2700-1950 A.

Numerous perturbations were easily recognized in

all branches. Using a 6.5-m focal length grating

6
with dispersion of 1.2 A/mm, he obtained the

rotational structure of the 4-11, 5-13, 6-15, 7-16,

8-17, 9-19, 10-20, and 10-21 bands. Gero further

reported [74] rotational structure for the 9-18,

11-20, 12-22, and 13-24 bands, and, in addition,

gave a Deslandres table of 84 band origins calculated from the band heads with a positive correc- (B'+B")

tl0D ° f , making use of previous data

4(B'— B")

[209, 73].

Table 4 gives an extensive list of band origins

which includes several additions of low accuracy

which supplement the Deslandres table of Herzberg [99, p. 156-7]. Herzberg’s table is mainly

that of Gero [74] with slight modifications and

numerous additions of low accuracy. The A-X

system origin is at 64746.5 cm-1 [209].

The heads of the 14-23, 15-25, and 16-25 bands

listed by Estey [60] deviate by +13.2, +14.8,

and +21.7 cm-1

, respectively, from Read’s

formula. Gero [74] believed that the appearance

of these bands was due to accidental accumulation

of lines, where strong overlapping is observed.

The first of these heads lies close to a band reported

by Kaplan [125] at 2518 A, and the third lies close

to a band of the 3A system (c-a) . Gero concluded

from this evidence that the v=13 level of the A

state was the last before dissociation. However,

Tanaka, Jursa, and LeBlanc [255] have since

observed the A state to v=20.

Schmid and Gero [228] reported the measure- ment and rotational analysis of many bands by

Kelemen [in a dissertation], including 1-8, 2-9,

2-10, 3-9, 3-10, 3-12, 4-10, 4-12, 4-13, 5-11, 5-12,

5-14, 6-13, 6-14, 7-14, 7-15, 7-17, 8-16, 8-18,

8-19, 9-17, 9-20, and 10-19. From these data

and those of Read [209] and Gero [73, 74], they

obtained formulas for the rotational constants for

both the Xx 2+ and A1 !! states. Schmid and

Gero [228] suggested that Read should have included a higher power of J in his expression for

F„(J), which would have resulted in slightly

larger B„ values. The calculation of B„ for the

strongly perturbed A state follows the method

of Gero [71]. Least squares fitting to the observed

data gives for A1 !! : B5 =1.6116-0.02229++3+) —

0.000105 (v++2)

2 (table 1). Brons’ [31] rotational analysis of the 10-19, 10-20, and 10-21

bands gives B[0 , B^, B'2

'0 , and B«, slightly smaller

than the values of Schmid and Gero [228].

Tschulanowsky and Stepanow [262] have given

the rotational analysis of the 3-8, 3-7, 2-8, 2-7,

2-6, 1-6 and 1-5 bands, including the determination of rotational constants and a discussion of

various perturbations of the A state. Twentyfour bands were observed with a dispersion of

8.4 A/mm (with resolution of lines separated by

0.07 A), and details of the three best are given.

Branches were observed up to J values of 35.

The three best bands for analysis were 3-8, 2-7,

and 1-6. The R branches were measured very

inaccurately and their details are not given.

Onaka [182] has looked at the 6-13 and 6-14

bands with a vacuum echelle spectrograph of high

resolution (~ 170,000) and high dispersion

(0.30-0.26 A/mm). Earlier attempts at analysis

of the lower rotational levels in A1 ]!, y=6 was

prevented by the complicated structure due to overlapping of the v=6 level by levels of the

d?Ai and a

/3 2+ states. Several perturbations

were found (see sec. 4.1). The lines of the 6-14

band are not given. A formula for the rational

structure of the v= 6 level is given by Onaka from

an unpublished work on the Fourth Positive

system:

Ts=6 (A1 n) -74197.44 +1 . 4616J( J+l).

Tanaka, Jursa, and LeBlanc [255] reported on

the absorption spectrum of the Fourth Positive

system in the vacuum UV for the first time since

the pioneer work of Leifson [149], and Hopfield

and Birge [104]. Using rare gas continua as

sources, Tanaka et al., observed new bands and

extended known bands to shorter wavelengths, all under low resolution, covering the spectral region

of 1177-1544 A. The (+-0) progression was

observed for v'=0 to 20; also the (+—1) progression for v' =0 to 13. In addition, the isotopic

C

13 016 band progression (+-0) was observed up

to +=17 (not including 16). Tanaka et ah,

used pure CO in an 8-cm long absorption cell, at

pressures of 0.01 to 600 mm of Hg. The spectrograph used was a 2-m focal length normal incidence

type with a dispersion of about S A/mm. The

absorption band positions are given in table 3b;

the observed isotopic bands of C

130

16 are given

in table 5. Several unidentified bands which

were found are given in table 35b.

McCulloh [157a] and McCulloh and Glockler

[157b] first studied emission by C

13O

lfl in the

positive column of an uncondensed discharge at

low current density in C02 in the spectral region

of 1900-6500 A. They reported vibrational

analysis of 35 bands of the Fourth Positive system

7
and rotational analysis of bands in the (Q-v")

progression of the Angstrom system (B 1 ^—

A

1 !!).

Band origins were obtained from the head measure- ments by using rotational constants of Schmid

and Gero [228] and the equations for the isotope

effect. Low resolution precluded rotational analysis. The observed emission heads and origins

of the isotopic A-X bands are given in table 5a.

McCulloh and Glockler [157b] believed that

Read’s [209] vibrational formula for the ground

state was good for higher vibrational levels of

C

12016

. However, they assumed that his results were unduly influenced by errors in the short wavelength heads due to poor standards, and were not

consistent with more recent infrared measurements.

Hence, they fitted molecular constants for the

normal and isotopic species which represented

both Read’s data and the infrared data of Lagemann et al., [139]. Slightly different constants

have recently been calculated by Benedict [17] to

fit the most recent infrared data as well as that for

the A-X system. (See table 1.) Vibrational

constants for the A1 !! state of C

130le were obtained

[157] from Read’s values for the normal isotope

and the ratio of reduced masses. These are included in table 37.

High dispersion absorption spectra in the

vacuum UV region have recently been photographed by Herzberg and Bass [100], and by

Wilkinson and Tilford [276]. Several previously

unobserved transitions are included in these

studies, as well as bands of the v" =0 progression

of the A-X system up to v'=20, some bands of

the v" =l progression, and also isotopic (C130

16

) A-X bands. The rotational analyses of these

bands should provide definitive values of the

rotational constants for the A1 !! state and precise

vibrational quanta for this state [238a].

3.2. B

1 S+ —

A

1 !! Angstrom System (6620-4120

A) V

In 1875, Angstrom and Thalen [see ref. 23] 5 observed a group of bands which became known

as the Second Positive system of carbon. Fifty

years later, analysis by Birge [23] showed that

this system, which now bears the name of Angstrom,

arose from the allowed transition B^"1- —

A

1 ]!

in carbon monoxide. This system has been a

fertile ground for study because of the numerous

* The data of Angstrom and Thal6n, as well as fine structure observations

of Loos and head measurements by Watts and Wilkinson at the turn of the century, are also listed on p. 277 of Vol. V of Kayser’s “Handbuch der Spectroscopie” [127a].

perturbations and suspected predissociations of

the A state. These single-headed violet-degraded

bands have also been observed for the isotope

C

13016

. Band heads and origins for the normal

isotope are given in table 6; the isotopic (C 13016) heads and origins are given in table 7. Rotational

constants for the A and B states are given in

tables 37 and 38, respectively.

Included among the original observations were

° o weak bands at 4301 A and 4581 A which were

later identified [23] as possibly belonging to the

v'=2 progression but which lay to wavelengths

longer by more than 10 A from the expected head

positions. Johnson and Asundi [121] believed

that these two bands belonged to another system.

Only one other band with v'—2 has been reported

[255], but its identification is also uncertain since

the B state is predissociated in levels y=0 and 1 and presumably also in v=2 at J=0. Another

uncertain band, included as 0-6 by Birge [23], lies about 8 A to longer wavelength from its

expected position. A band observed by McLennan, Smith, and Peters [158] at 7246 A, has

not been reported elsewhere.

The first rotational quantum analysis of the

0-1, 0-2, 0-3, and 1-1 bands was made by Hulthen [108]. The 5610 A band was the strongest

observed, and incorrectly assigned as the 2-2

band. The correct vibrational quantum assignments are obtained by reducing Hulthen’s v' by 2

and raising his v" by 1. Bands were also observed at 6078 A, 6622 A, and 4511 A, but the

structure of these could not be determined at

that time.

Jasse [115] has given the rotational analysis for

the 0-0 and 1-0 bands. His source was a high

voltage electric discharge in C02 at low pressure.

Spectra were taken using a grating spectrograph

of 3.25-m focal length; claimed precision is ±0.01 A. Hulth&a [108] and Jasse [115]

believed that the structure of the 0-0 and 1-0

bands was more complicated than the others of

this system, having two additional branches.

Birge [23] believed that the additional branches

were probably spurious, while Johnson and Asundi

[121] thought that the additional branches might

originate from overlapping lines of C2 . Later,

more accurate work by Rosenthal and Jenkins

[216], and Schmid and Gero [224] indicated that

perturbations of AX II, v=0 were responsible for

the confused structure of the 0-0 and 1-0

bands, resulting in displacement of the band heads

from then- expected positions.

8
Johnson and Asundi [121] observed the 0-0 and

0-1 bands in the first order of a 21 -ft focal length

grating spectrograph (supplanting Jasse’s measurements), and re-evaluated constants from Hulthen’s data [108]. They also gave the first preliminary evaluation of the fine structure of the

0-4 and 0-5 bands, with details given by Asundi

[5]. Referring to Jasse’s analysis of the 4511 A

band, they considered the lines at 22172.3 cm-1 and 22175.7 cm-1 as extraneous to the band.

Also they relabeled the line at 22171.8 cm-1

as Q (1).

New measurements of fine structure of the 0-0,

0-1, 0-2, and 0-3 bands were made by Rosenthal

and Jenkins [216] primarily to study perturbations,

though the results are not completely reported in

this work. (See sec. 4 on Perturbations.) It was

found that Jasse, and Johnson and Asundi, did

not correctly identify P and R lines above J=S

and Q lines above J=10 because of the large

increase in A-doubling in the region of a perturbation. [See fig. 1 of ref. 216—the difference

between the R and Q deviation curves.] Corrections to Jasse’s assigments for several lines of

the 0-0 band were made [216].

Coster and Brons [44] have given the rotational

analysis of the 0-0, 0-1, 0-2, 0-3, and 0-4 bands

in order to interpret the perturbations of the

v=0, 1,2, 3, and 4 levels of the A1 !! state. Thendischarge tube produced strong Angstrom bands

relative to the background of C02 bands. A

value of o-H (0-0) for the system of 22163.1 cm-1 was obtained. (Herzberg [99] lists 22171.3 cm-1

.) (See also sec. 4.1.)

Schmid and Gero [224], from observations in

second and third order using a 21 -ft focal length

grating spectrograph, gave improved measure- ments of the 0-0, 0-1, 1-0, and 1-1 bands. They

obtained rotational constants for the B^4" state,

and in addition, AG(^) =2082.07 cm-1

. McCulloh [157a] and McCulloh and Glockler

o [157b] have reported the B-A Angstrom bands

due to C

130

16 emission in the positive column of an uncondensed discharge. The perturbations in

the A1 !! state are discussed at some length [157a]

(see sec. 4.1) and details are given of the rotational analysis of the (0-r") progression including

the 0-1, 0-2, 0-3, 0-4, and 0-5 bands, and the 1-1

band. The C

13016

, 0-0 head lies to the red of the

C

120

16 head. Overlapping by Third Positive

bands (6

3 S

+ —

a

3 II) prevented rotational analysis

of the 0-5 isotopic band. Overlapping of regular

and isotopic bands required 0-1 branches to be

identified by a method analogous to the LoomisWood method (see pp. 191-2 in Herzberg [99]).

For the 0-2 band there is almost complete superposition of the P and Ii branches such that R(J) ~

P(J+10). The region beyond the tail of this

band and also the 0-3 band is quite free from the

general background caused by C02 bands. Therefore, these bands are useful when searching for

predissociation in the B1 2+ state. The 0-4

band has a near superposition of the P and R

branches.

Since only one v" progression was analyzed no

information can be obtained about the vibrational

constants of the Bx 2+ state. (See Schmid and

Gero [224].) Values for aj e and w exe for the isotopes

C

120

16 and C13016 were approximated from a study of the isotope effect. The abnormally large

value of (j) exe for the B state suggests probable

rapid convergence of levels. (See table 9a and

footnote Bx 2+ to table 1.)

Douglas and Mqller [56] have photographed

under high dispersion and analyzed the 0-1, 1-1,

and 0-2 Angstrom bands of C

13 0

16

. The bands

were observed in a discharge through 02 in a tube

containing carbon, using a 21 -ft focal length

grating spectrograph with a reciprocal dispersion

of 2.5 A/mm. Their primary aim was an examination of reported predissociations of the C

120

16 and C

13016 molecules (see sec. 5.2).

3.3. Ax n Herzberg System

(5710-3680 A) V

The Herzberg system, which partly

overlaps the B—A Angstrom system, consists of

eight observed bands of the v'=0 progression. No

bands of this system have been observed with v' >

0, but the level C, v=l has recently been observed

in the C—X system [276]. This suggests that

there is either predissociation for z/>l, or that a weak transition is expected from the FranckCondon principle. Table 8 lists the heads and

origins of the C—A system. The rotational constants for the C

1 2

+ state are give in table 39 and

those for the A1 !! state in table 37. Three bands

of this system were first observed by Duffendack

and Fox [5S] who thought that the new bands

belonged to the Angstrom system because of

their similar structure. Herzberg [97] observed

eight bands and recognized these as belonging to a new system whose upper state he incorrectly

designated as *A, by analogy with the Grotrian

diagram for the Mg atom, as was done at that

9
time, following Mulliken. The new level lay

between the B

x 2

+ and c

3 2

+ states. Asundi [3] and Asundi and Johnson [121]

observed the 0-1, 0-2, and 0-3 bands using a

21-ft focal length grating spectrograph in first

order (wavelengths of the stronger lines are believed accurate to within 0.01 A). Fine structure analysis showed the C state to be 1 S. The

Q branches were reported to be twice as strong as the P and R branches. For the A1 ]! state there is no combination defect up to J=17 (limit of

observations here), indicating no appreciable

A-doubling to high rotational quantum numbers.

This is so for v"=l to 5, not for v"=0, for which

combination defects occur from almost the lowest

J values. [See ref. 224.] For the 0-0 band, only

the calculated position is given, because of confusion with a band associated with the Third

Positive system of CO (6

3 S+ —<z3 n). A band

reported by Deslandres at 3893 A which Wolter

[277] did not observe is the 0-1 band of the C-A

system.

Schmid and Gero [224] observed the 0-0, 0-1,

0-2, 0-3, and 0-4 bands of the C-A system.

From the rotational analysis, a value of Bo' of

1.9422 cm-1

is obtained.

3.4. Hopfield-Birge Systems (1810-950 A)

a. C‘S+

, E!n, F(iS+),6 GOD), and 6

3 S+—

X

J S+.

In 1927, there appeared preliminary reports

by Hopfield [103] and Hopfield and Birge [104]

concerning the observation of seven band systems

of CO both in emission and absorption. These

transitions, all going to the ground state, included

four whose upper states had not previously been

recorded: a/3 2

+

, E

1 !!, F(X S

+

), and G(1 II). Strongest absorption was to the highest lying levels (G,

F, E, C). Full details of this work have never been published. Though several of the bands

have since been observed elsewhere, only the

a'3 2

+ —

X

1 2

+ system has been studied in detail

[101] and will be discussed in section 3.4b. The

other six transitions will be discussed together

since the information about them is incomplete.

Recently, however, high dispersion measurements

have been made of the C-X, 0-0, and 1-0 bands,

with y' = l observed for the first time [276].

The observed band heads of all six systems are given in table 9. The rotational constants for

6 It is not certain whether the F state is singlet or triplet. (See sec. 5.2f and table 1, footnote F02+).)

the B, C, E, and b states are given, respectively

in tables 38, 39, 40, and 43.

Read [209] observed several emission bands

belonging to the B-X, C-X, and E-X transitions.

Tanaka et al. [255] have seen some of these in

absorption. Since the Be values of the three

excited states and the ground state are roughly

the same, each band had the appearance of a doublet with a clear center under low resolution.

Identification of the B-X, 2-0 band [255] is rather

uncertain.

Recently, Tilford et al. [257] have identified

the E state as 1 n from analysis of the violetdegraded 0-0, E-X band observed in absorption

under high dispersion. This identification con- firmed the theoretical prediction by LefebvreBrion et al. [147]. A-doubling is about 0.2-0.

3

cm-1 for J~20. (The J'=31 level is perturbed.)

The isotopic (C130

16

) 0-0 band was also analyzed.

(Table 40.)

b. a'3 S+-X1 S+ (1810-1280 A) R

Of all the band systems of CO which were

originally observed by Hopfield and Birge [103,

104], only the dipole forbidden a'3 2

+ —

X

x 2

+ system has been extensively studied (by Herzberg

and Hugo [101]). A long progression of bands

has been observed up to v'=23, because of the

large difference in internuclear separation between

the two states involved. The upper state of this

system is responsible for many perturbations of

the A1 !!, 6

3 2+

, and a

3 n states. The band heads and origins of the a'—X

system are given in table 10. The rotational

constants for the X and a' states are given in

tables 36 and 41, respectively.

Five bands of this system were first reported

in absorption by Hopfield [103] with the one at

1696.9 A designated as the 0-0 [104]. On the

basis of an additional band found by Birge at

1731 .2 A, Estey [60] raised the vibrational quantum

numbering in the a' state by one unit. The final

assignment was deduced by Beer [16] from rotational perturbations in the 6

3 2+-a3 n Third Positive bands caused by the a

/32

+ state. This raised

the quantum numbering of Plopfield and Birge by

three units.

Recently, only two papers have dealt with this

system [255, 101]. Tanaka, Jursa, and LeBlanc

[255] have seen a long progression of these singleheaded red-degraded bands under low resolution.

Because a short absorption cell was used, the 0-0,

10
1-0, and 2-0 bands were not observed. Herzberg

and Hugo [101] observed this progression in absorption under high resolution in the region 1810-1280

A. These forbidden bands were photographed in

fourth and fifth orders of a 3-m focal length

spectrograph, with reciprocal dispersions of 0.63

and 0.50 A/mm, respectively.

In most of the bands [101] all four predicted

branches, i.e., PP, PQ,

R

Q, and RR, are observed

and give the appearance of a doublet structure.

The order of the sublevels of the a' 3 2

+ state is given as F3 +>Fi+i>F2 . The triplet splitting for the a' state is approximately constant for N>5. [N was formerly

called K.] A discussion of splittings for N+5

determined from other bands has been given by

Gero and Lorinczi [SO]. The sum of splittings

[2X+y] in corresponding members of the P and It branches is approximately constant, with small

change of X with v. The rotational analysis results in the following

formulas for the a' 32+ state.

<r 0 = 55822.92 + 1230.651 +'+ £) —1 1 .013+'+ 1)

2 +0.07378+'+|) 3 —0.001 15+' + 1)

4 — 1081.59.

[Ref. 101 used 1081.74 for the ground state zero- point energy.]

Bs =1.3453 — 0.01 872++ 1)

+ 0.000205 ++|) 2 —0. 0000051 ++ 2 ) 3

-

D' was found to be about 6.5X10 6 and varied

little from v'=2 to 23.

Only a perturbation in v' —4 at approximately

J=20 was observed. The perturbing level is a

3 n, v=7, which has not been observed directly.

Other perturbations which occur at high J (due

to A1 !!, a

3n, and 63 2

+

) were not observed.

3.5. a

3 n—

X

4 S+ Cameron System

(5800-1770 A) R

The a

3 n-X1 S+ transition consists of quintupleheaded bands, degraded to the red, covering the

spectral region 5800-1770 A. This forbidden

intercombination system is overlapped by the

B2 S+ —

X

2 S+ First Negative bands of CO+ and

the A-X system of CO. Recent high dispersion

measurements by Rao [201] have provided an

accurate value for the vibrational term interval

AG (|) of the a

3 n state, but there is still lacking

an accurate value of The observed band

heads of the a

3 II —X'2+ transition are listed in

table 11, the origins in table 12. Rotational

constants for the a

3 II state are given in table 42.

The band system bearing his name was first observed by Cameron [39] in an uncondensed

discharge in neon with a trace of CO ; the following

year it was seen in absorption by Hopfield and

Birge [104]. Johnson [119] first identified these

bands as due to transitions from the lower states

of the Third Positive system to the ground state

of CO, and assigned vibrational quantum numbers

to the bands. Knauss and Cotton [131] also

observed these bands at low pressure in an electrodeless discharge in CO.

Schmid and Gero [232] observed the 4-8 band

in a Geissler discharge in neon. Because of the

coincidence of one head of this band and the

intense red-degraded band reported by Kaplan

[126], Schmid and Gero believed that the level

reported by Kaplan at 38820 cm-1 above X was

not real. (See footnote (K) of table 1.) Herman [94] reported selective excitation of the

a-X system between 5000-2000 A in a feeble

discharge through CO at low temperature. Details are not given except for mention of the R2 (or Q3 ) heads of the 2-4 and 0-1 bands, at 2299 A

and 2159 A, respectively. Comparison was made

between the Ri and Q2 heads calculated from

vibrational constants given by Johnson [119] and

the faint low dispersion measurements of the night

sky by a number of authors. The apparent

agreement for a number of bands suggested to

Herman the possible presence of the a-X system

in the night sky. No other mention has been

made of such correlation, and this agreement may

be fortuitous.

Recently, Tanaka, Jursa, and LeBlanc [255]

observed the v"=0 progression in absorption

under low resolution. Unlike other intercombination bands observed by them, this progression did not develop to high v' because of the

Franck-Condon principle. [Note that ref. 255

lists vacuum wavelengths.]

The first high dispersion measurements of this

system in absorption were those of Gero, Herzberg,

and Schmid [79] who gave the fine structure

analysis of the 0-0 and 1-0 bands. This was the

first example of analysis of the fine structure of a

3 II— *2 transition. At least for large J the a

8 n

state is close to Hund’s case (b). Thus the

quantum number N (formerly K) has meaning

for the rotational levels of both upper and lower

11
states in this transition. Two equivalent notations of the nine branches are given below:

Pi Qi Pi P2 Q2 B2 P.3 Q3 P.)

°P PQ

QP PP

QQ

RP QP

RQ

SP.

The combination differences which give AiFj.

for the 3 n0 component of the a state do not coincide

because of the very strong A-doubling of this

component.

Gero [76] used a Geissler discharge in neon

with a trace of CO to excite (in emission) the

a-X bands and, weakly, the A-X system. His

close examination of the work by Gero, Herzberg,

and Schmid [79] revealed the use of two unreliable

standard iron lines by Schmid and Gero, which

accounted for a discrepancy in their wavelengths.

Gero tabulated the rotational lines for the 0-0,

0-1, 0-2, 0-3, 1-3, 1-4, and 2-5 bands.

The most precise measurements of the a-X

system have recently been made by Pao [201]

who has given the rotational structure of the 0-0,

0-1, 0-2, 0-3, 1-3, and 1-4 bands seen in a Geissler

discharge. A 21 -ft focal length grating spectrograph was used in fourth and fifth order, with an

iron arc providing a comparison spectrum. Errors

in the combination differences for the 0-1 band

by Gero were clarified. Relative accuracy of the

line measurements [201] is estimated to be ±0.003

o

"* A. (A reproduction of the 0-1 band is given in

this reference.)

Rotational constants for the ground vibrational

levels are close to those obtained from infrared

measurements. Derived values for vibrational

quanta for the ground state are the best available

from electronic spectra of CO, but are inferior to

those determined from infrared measurements.

A value of 1714.61 cm-1

is obtained for the vibrational quantum AG (!) for the a state, confirming

the value obtained previously [79].

3.6. fc

3S+ —

c

3 n Third Positive System

(3820-2660 A) V

The Third Positive system of carbon,7 is composed of strong quintet-headed red-degraded

bands whose structure is characterized by in7 Deslandres called the Third Positive group all [CO] bands in the UV

region not belonging to the Fourth Positive group or Second Positive group (Angstrom system). Some authors refer to the »'=0 progression as Third

Positive and call the v’=l progression “5B”. The two together should be

treated as a single system.

tensity fluctuations due to perturbations of the

upper state. Since the upper state is also predissociated, only the v' = 0 and 1 progressions are known, the latter having been dubbed by Asundi

[4] as 5B, and at that time thought to be a new system. This is understandable because

violent perturbations of the 6

3 2

+ state drastically

alter the relative appearance of the two progressions. The original measurements by Deslandres

[127a, 23] in 1888, of emission from discharge

tubes containing carbon and oxygen, included

some bands down to 2295 A which turned out to

be part of the 3 A system (c3 2

+—a

3n). The

confirmed bands of the b-a system extend from

3830-2660 A. These vibrational heads are given

in table 13. The rotational constants for the

6

3 2

+ and a

3 n states are given in tables 43 and 42,

respectively.

The first assignment of vibrational quantum

numbers of the 6

3 2+ — a3 n system was made by

Johnson [119] who identified the lower state with

the upper state of the Cameron bands. Previously Wolter [277], using high resolution, had

observed five bands of the v' =0 progression. He

mentioned the repeated rise and fall of intensity

of the band lines and, in addition, reported the

appearance of weak diffuse lines between the main

lines. Later this system was observed by Duffendack and Fox [57, 58] who concluded that the

group of bands labeled by Johnson [119] as the

y' =4 progression constituted the v'= 0 progression

of a new system called 3 A.

Asundi [4] observed the b-a and 3A bands

in an uncondensed discharge using a 21 -ft focal

length grating spectrograph. Outside the first

(longest wavelength) head of these violet-degraded

bands were faint lines which decreased in spacing

toward higher wavelengths, formed a diffuse head,

and continued further with a gradual increase in

spacing. Asundi attributed the b-a system to a

5 2 —5 n transition. Birge [23] disagreed and considered the transition as

32—3 n, an assignment

later firmly established by Dieke and Mauchly

[54].

An extensive discussion of the spin splitting

and A-doubling in these bands has been given by

Dieke and Mauchly [54], who observed the 0-0

to 0-4 bands using dispersion of <lA/mm.

Budo [32] has used these data to obtain rotational

constants for the a

3 n state. Dieke and Mauchly’s

analysis established the transition as

3 2

+ —3 n, with

triplet (spin) separation of the 5

3 2 state unnotice12
able for J<20. The character of the A-doubling

and the number of missing lines near the origin

identified the lower state as regular 3 n, intermediate in coupling between case (a) and (b). From

a study of the Zeeman effect on this band system

Schmid [23G] showed that, beginning at about

N=22-23, the <z

3 n state belonged to coupling

case (b) . The 3 2 terms have separation <0.2 cm-1

for N up to about 20. The terms in order of decreasing energy are anomalous: Fi >F2 >F3

. The b-a bands represent a transition from case

(a) to case (b); i.e., the 3 n state already departs

from case (a) coupling for small N. Fifteen

branches are allowed by the selection rides, of

which fourteen were observed as well as the trace

of a fifteenth. Nine strong bands indicate coupling close to case (b). The five head-forming

branches are 03 , 02 , P3 , P2 , and Pi.

Many large perturbations, mostly far from the

heads, cause the characteristic intensity fluctuations first mentioned by Wolter [277], and cause

clustering of lines toward the tails. At high pres- sure the tails show characteristic triplets especially

in the 0-1 band at 2977 A. [See fig. 2 of ref. 54b.]

In front of the heads (at shorter wavelength) are

faint lines forming very weak series which do not

form heads. Dieke and Mauchly showed that

these are due to transitions with AN=3. It is not

certain whether these were the lines found by

Asundi [4]. Schmid and Gero [226] have reported clustering

of Q-branch lines in the v' = \ progression caused

by perturbations of the 6

3 2

+ state. The positions

of these perturbations converge to a limit which

seems to coincide with the predissociation limit

common to the y' =0 progression and to the B

state. Gero’s [75] report on the fine structure of

the 1-0 band has confirmed the predissociation of

the upper state between N=42 and 43.

Rotational analysis of the 0-4, 0-5, 1-4, and

1-5 bands has been given by Beer [16]. Perturbation of z/'=4 was observed and assigned

to a

,32

+. The molecular constants for the b state are somewhat uncertain. Schmid and Gero’s values

[226] are quoted by Herzberg [99]; i.e., B e =2.075,

oc e —0.033, Bi=2.025 cm-1

. Stepanov [246] has

criticized the way these values were determined

and his values are listed in table 1, i.e., B e = 1.986,

ct e =0.042 cm-1

. For AG(|) from measurement

of b-a bands Schmid and Gero [226] obtained 2109

cm-1

. Jevons [117] had previously listed 2214

cm-1 from the data of Asundi [4]. Gero’s [75]

estimate of 2198 cm-1

is the value listed in Herzberg. This value was obtained by extrapolation to

N=0 of the difference between the Q lines of the

1-0 and 0-0 bands. Stepanov [246] criticized

this value and used a different method to obtain

2188 cm-1 which is the value quoted in table 1. These constants should be accepted as only tentative and renewed attempt should be made to

determine them more precisely.

3.7. c

3 2+ —

a

3 n 3A System (2710-2300 A) V

Duffendack and Fox [57, 58] measured the

excitation potentials of several band systems of

CO, including five bands of a new system appearing

at about 11.1 eV. These bands had the same final

state as the Third Positive system, [6

3 2

+ —

a

3 n],

but originated from a state about 1.02 eV above

the b state. The new system was labeled 3A,

and bands were identified as the (0-v") progression for v" =0 to 4. The violet-shaded bands

were multiple headed.

Faint, five-headed bands of this system were produced by Asundi [4] in an uncondensed discharge in CO. The first and fifth heads are

strongest; hence, under low dispersion the bands

appear double-headed. The electronic multiplet

separation of the measured extreme heads is largest for the 0-0 band, and, as with the Third

Positive bands, decreases for higher vibrational

states. An equation for the heads is given by Asundi [4]

<t=43542. 5

-(1726.5z/' — 14.4y"2).

43612.

4

Schmid and Gero [230] excited intense 3A bands

in a discharge through neon in a Geissler tube

with carbon electrodes and gave a preliminary

report on the 0-1, 0-2, and 0-3 bands. They

detected 12 branches in each band, the remaining

branches being weak and overlapped. Six branches

are head forming: 03 , 02 , P3 , P2 , Pi, and Qt in

order of diminishing wavelengths. The nature

of the branches shows the upper state to be

3 2, with negligible multiplet splitting.

Gero [77] reported the detailed rotational

analysis of the 0-1, 0-2. and 0-3 bands observed

at a dispersion of 1.3 A/mm. A predissociation

in this system is observed at about 11.5 eY. 'The

13
combination differences for the a

3 n state agree

well with those of the b-a system which confirms

the order of the bands and band lines and the

2

+ character of the c state. A value of B0 = 1.9563

cm-1

is derived.

The last observed lines of the R3 branch of the

0-1 3A band lies in the region of a spurious predissociation in the P branch of the red-degraded

9-18 Fourth Positive band. The rotational analysis of the 3A bands shows that the apparent

increase of intensity of some of the Fourth Positive

band lines [74] in this region are caused by superposition of certain 3A lines.

The band heads of the 3A system are given in

table 14, and the rotational constant B 0 = 1.9563

is included in tables 1 and 44.

3.8. £p3S+—

a

3 n Asundi System (8590-3900 A) R

The multiheaded bands of the a'-a system have

been studied mostly under low dispersion, with

only a few rotational constants determined for

the a' state from their analysis. More accurate

values for these constants are available from analysis of another system [101]. Two bands which

were believed to originate from levels with y>30

in the a' state [78] most probably belong to a new

3 2+ state whose term value is uncertain. The

observed vibrational heads of the a' 3 2+—

a

3 II system are given in table 15. Rotational constants

for the a' and a states are given in tables 41 and

42, respectively.

McLennan, Smith, and Peters [158], using low

dispersion, observed a large number of reddegraded bands produced in a long, high-voltage

discharge tube filled with CO. (A number of

these bands which have not been identified are

listed in table 35c.) Shortly thereafter Asundi

[4] discovered 16 red-degraded bands of the system

bearing his name which were overlapped by the

d

3 Ai—az U Triplet bands below 5700 A. The

a'-a bands appear double headed under low dispersion, but have five heads when seen under

higher dispersion.

o By assuming the band at 8592 A was the 1-0,

Asundi assigned vibrational quantum numbers.

A new term of the a/-X system found by Estey

(at 57763 cm-1

) [60] required the v' assignments

to be raised by unity. The correct v' numbering

was finally established by Beer [16] who indicated

that a perturbation of the a

3 n, v=4 term is caused

by a

/3 2+

, v=0, which required Asundi’s original

v' values to be raised by three. [See ref. 80.]

Knowledge of the a'-a system was considerably

extended by the observations of Garg [68].

Numerous impurity CO bands were observed

during the preparation of a discharge tube for the

study of emission from SnBr4 vapor. The band

positions are assumed accurate to ±4 cm-1

. Garg’s formula, fitted to both his and Asundi’s

measurements, is given below with v' numbering

of Gero and Lorinczi [80].

<rH =7213.8 + 1218.1(z/ +|) —9. 5 (?/ +!)

2 - 1 740.9 (v" +1) + 14.4 (v" + 1)

2

. A few bands which cannot be fitted in this system

are listed separately, and assumed members of an unknown system. (See table 35c.) Garg’s

table of band heads shows increasing deviation of

observed-calculated differences for z/>16. It is not presently known whether such deviations

arise from perturbations, or are due to incorrect

identification of particular subheads used to

calculate these deviations.

Schmid and Gero [233], in a note, reported

several red-degraded bands near the heads of the

violet degraded 6

3 S

+ —a.3n Third Positive system.

An especially strong band is observed at 2670 A

in a Geissler tube discharge in neon with carbon

electrodes, in the presence of very little oxygen.

In another brief communication Schmid and Gero

[231] ascribed the bands as due to a

3 2—a

3n

transition. The upper state, provisionally designated as fz, was suspected as including high

vibrational levels of the a/ 3 2 state. This was

supposedly confirmed by Gero [78], but Herzberg

[99] believed the bands belonged to another state

and confirmed this indirectly in later work [101].

Gero and Lorinczi [80] have given the rotational

analysis of the 8-0, 9-0, 10—1 , and 11-1 bands

which were observed in emission. The 8-0 band

is weaker than the rest and its branches are not

given. The high dispersion measurements are

relatively free of overlap by other systems, and

allowed measurement of lines to a few hundredths

cm-1

. Rotational constants for a'32+

, v—8 to 11 are obtained. A long extrapolation of these

[which is usually dangerous] gives the molecular

constants Be = 1.331 cm-1 and a e =0.016 cm-1 which are the values listed by Herzberg [99].

The rotational constants for the upper levels are smaller by only about 1.5 percent than those

given previously from perturbation data [234a].

From more recent work on the a'3 2

+ —

X

! 2

+ system, Herzberg and Hugo [101] obtained im14
proved constants B t,= 1.3453, a e =0.01872, and

y,,= 0.000205 cm”1

. The spin splitting of the 3 2 state is rather large.

For the 10-1 band, the splitting is constant

above N=5. The splitting (in cm-1

) is almost

the same for each of the bands as is seen below:

f3 -f2 Fi-F»

9-0 1. 40 0. 97

10-1 1. 37 . 98

11-1 1. 40 1. 01

(See ref. 80 for a correction to table 2 of ref. 78).

3.9. tfAi-am Triplet System (7500-3770 A) R

The d

3Aj—

a

3 n Triplet bands of CO are a fairly

extensive system of moderate intensity spanning

the visible region of the spectrum. Merton and

Johnson [160], in studying the effect which the

presence of helium had on band spectra of carbon,

first isolated two progressions of this system.

These red-degraded bands were later assigned to

CO when Birge [21] identified the lower state as a

3 n and gave a vibrational analysis. Extension

of the system to longer wavelengths by Asundi

[7] required an increase in v' assignments by two

units. Carroll [40] has reported that the numbering for the d state vibrational levels should be

increased by one more unit. Only recently the

upper state was identified [40] as

3 A t , following a

prediction of the A character by Mulliken [171].

Kovacs [137] has explained the inverted character of this state which is not expected in first

order from a -rV configuration. Band heads are given in table 16; origins in table 17. Rotational

constants for the d

3 A* state are given in table 45.

Asundi [7], from study of three bands at longer

wavelength, concluded that the band at 15540

cm-1 was not 0-0, and that the v' assignments

as listed by Gero and Szabo [82] should be raised

by two. The bands were found to have five

heads. He was not certain whether his band at

13303 cm-1 was definitely 0-0, and speculated

that the system origin might be at longer wavelength than his range of observation.

Herman and Herman [92, 96] observed emission

of d

3Ai—a

3 IT Triplet bands in a low current discharge in neon with traces of CO at liquid nitrogen

temperatures. Under these conditions bands with

high v' predominate. Bands with v'=G [add 3 to

the v' assignments of Herman and Herman] are

relatively weak compared to intense bands for

v' =5 and 7. The bands with v' = 12 are relatively

weak and those with v'=13 are enhanced compared with those for U= 14. A new system of

triple-headed bands was also observed and is discussed further in section 3.14.

Recently Sato [219] used a 33.3 MHz discharge

to produce more than 40 rather intense bands of

the d—a system. His low dispersion measure- ments included almost all bands observed previously as well as the 12-0, 5—1, 6-1, 6-2, 7-2,

17-2, 18-2, 19-3, 20-3, 17-4, 21-4, and 22-4.

His v' values should be raised by three units. Uncertainty in the shorter wavelengths is about

0.5 A; uncertainty in the longer wavelengths is about 1 A.

For a number of bands, Sato’s measurements

differ considerably from those of several other

authors. This raises questions about quantum

assignments for other bands observed by Sato.

This system should be reexamined to clarify the

band identification.

Gero and Szabo [82] have given the rotational

analysis for the 3-0, 4-0, 6-0, 7-0, and 9-1 bands.

(Their original v' assignments are too low by

three units.) The fine structure was interpreted

as showing the transition to be d

3 IIj—>a

3 II r

. The

upper state was later correctly identified as

3 Ai by

Carroll [40]. Gero and Szabo observed these

bands in a Geissler discharge in neon with traces

of oxygen. The bands also appeared under

favorable conditions without the presence of a noble gas. In the latter case there was overlap

with the Angstrom and Asundi bands, B

1 2

+ —

A

1 !! and o/3 2

+ —

a

3 IT, respectively.

Twenty-seven branches were observed, doubled

because of A-doubling. It was established that

A-doubling of the band lines agreed with that

of the a

3 II state (from the 6

3 2

+ —

a

3 n Third Positive

bands) and that the A-doubling of the d term was

immeasurably small. Rotational constants, coupling constants A, and Y=g for the d state were

calculated from combination differences and the

Fi—

F

3 differences based on Budd’s formulas [32b]

for a transition between two triplet II states in

intermediate coupling between cases (a) and (b).

Corrected values are given by Carroll [40].

The origins of four bands were calculated by Gero

and Szabd [82] using an average of nine Q-branches

whose series were extrapolated to J = 0. Based

on these zero positions the vibrational term differ15
ences were calculated for the d term. A formula

fitted to the correctly numbered v" = 0 progression

is given here as <r0 (v' — 0) = 11598. 50 + 1152. 58

iv,Jrh) —7.2812 (++£) 2 —0.1125 (+ + §)

3 which

gives ex0 (0 —0) at 12,172.96 cm-1

. Carroll [40] has given the rotational analysis

of the 3-0 band based on high resolution measure- ments and has shown the upper state to be 3 A, in

agreement with electron-configuration theory and

not 3 IIj as indicated by Gero and Szabo [82].

Mulliken [171], on the basis of LCAO-MO calculations for the lower excited states of CO, had

predicted a

3 A state at about the observed energy.

Carroll’s work was initiated to clarify the nature

of the upper state, and is the first reported example

of a

3 A->3 IT transition with nonnegligible (multiplet) splitting. The source used was a discharge

through flowing helium with a trace of CO. Of

the several bands observed, the one at 6401 A

was analyzed because it extended to high J and

was relatively free from overlapping by other

structure. All 27 branches were observed, al- though sometimes the A-doublets were not resolved

for lower J. There are nine subbands, each composed of three doublet branches, although the

branches going to 3 n2 of the lower state are only

resolved at higher J. The 3 A* state is case (a)

at low J and changes to case (b) at higher J

(See fig. 1 of ref. 40.) The a state also is case (a)

at lower J. Carroll’s measurements agree well with the

previous ones of Gero and Szabo for the 3 -0 band,

with several differences in classification of lines.

In addition, some of Gero’s assignments at low J

seem to be spurious. Detailed evidence is given

for the assignment of the upper state as 3 A,, including confirming evidence from the intensity distribution in the fine structure. At that time there

had been no theoretical calculation of branch intensities for a

3 A—3 II transition, but such formulae

have since been obtained by Kovacs [136], for

various coupling conditions of the states involved.

The energy formulas of Budo [32b], although

good to a first approximation, do not give the rotational term values of the 3 A* state with sufficient

accuracy [40]. This deviation between the observed and calculated energies, which affects most

strongly the middle multiplet component, is ex- plained by Kovacs [137] as arising from the joint

effect of two factors normally neglected: (1) spinspin interaction, and (2) spin-orbit interaction by

mixing with a nearby state, probably *A. No X A

state has been observed directly, though a possible

perturbation of A1 II, y=0 by such state has been

mentioned by Rosenthal and Jenkins [216].

3.10. e

3S

- —

X

1 ^

Transition (1540-1240 A) R

A forbidden electronic transition, g

3 2

_ —

has been observed by Herzberg and Hugo [101]

in the vacuum UV region. They observed a long

y" =0 progression of weak, red-degraded single

headed bands in absorption by use of a 3-m focal

length vacuum spectrograph, at dispersions of

0.63 and 0.50 A/mm. These bands have also

been seen under low dispersion by Tanaka, Jursa,

and LeBlanc [255]. The existence of the g

3 2~

state had previously been inferred from perturbations in the B-A bands [101] and in the A-X bands

[234b]. Many g-X bands are overlapped by bands

of the A-X, a'-X, and d-X transitions [101, 255].

Table 18 lists the band heads and origins of the

g-X system. Rotational constants for the g

3 2~

state are given in table 46.

The observed progression began with a relatively

strong band at 64816 cm-1 which was labeled 0-0.

Since then, two bands have been found at longer

wavelength [100] which suggested raising the v' values reported earlier by two units. Fine structure analysis of these bands [238a] showed conclusively that the v' values of Herzberg and Hugo

should be raised by unity.

Fine structure has been determined for the 5-0,

6-0, 7-0, 9-0, 11-0, and 13-0 bands, which resemble a

1 II— x 2 transition, but with the Q branch doubled. Electric dipole selection rules (+«— —

,

Aj=0, ± 1) indicate five branches are expected for a

3 2“ — transition which is possible because of

spin-orbit interaction: Q, QP, Q R, S R, and °P.

Recall that the selection rule prohibiting —

transition does not apply to intercombinations

[220]. In the 3 2 state, Fi and F3 sublevels (J=

N ± 1) lie close together, with the QP and QR

branches nearly coincident and separated from

the Q branch. These conclusions are confirmed

in the observation of the 8-0 band, for in most

other bands, the three Q-form branches are not

resolved. Flerzberg and Hugo [101] have made

no quantitative intensity measurements, but

have compared the intensity factors of the Q-form

branches as given by Schlapp [220].

16
The formulas fitted to their data (with revised

quantum numbering) are given below:

B/ = 1.2848 — 0.0181 (z/ +|) +0.0001 (v' +§)

2

*(,(»' —0) =64236.32 + 11 13.167 (»' + £) —9. 596

(y/ + i)

2 +0-00587 (+ + 1)

3 — 1081.59

where the last number is the zero-point energy of

the 3.11.X state.

C

1 S+ —

u

,3 E+ Knauss System (3250-2930

A) V

Knauss [130], in an abstract, reported four

violet-degraded bands obtained in an electrodeless

discharge through CO. These were identified as belonging to C

1 2

+—

a

/32+ (table 19). More recent

data on the a' state indicates that the v" values

should be two units larger than those quoted by

Knauss.

3.12.

Kaplan Bands (2750-2520 A) V

A. In a brief note Kaplan [125] reported three

bands forming a new system when a trace of CO

was excited in a long atomic hydrogen tube. The

bands resembled the 3A system (c 3 2

+-^a3 n)

,

each having six heads and degraded to the violet.

The transition is attributed to K—

a

3 n, the upper

state being tentatively identified by Kaplan as a metastable quintet. These bands do not appear

under ordinary conditions. (Schmid and Gero

[227] have speculated that these bands may be the

v' =2 progression of the b —a Third Positive system.) Assuming v' = 0 yields T0 = 89889 cm-1 (above X) for the upper level. The bands are

listed in table 20.

B. Kaplan [126], in an abstract, reported an

intense single band at 2575 A, similar in structure

to the A1 !!—

X

1 ^

Fourth Positive bands, hence

degraded to the red. This band was discovered in

quenching mercury resonance radiation by CO.

Schmid and Gero [232] indicated that this band

coincided with a head of the 4-8, a

3 II —

X

! 2

Cameron band (which according to Cameron

himself was the most intense band of the system)

and disputed the reality of the 2575 A band as due

to a new CO transition. Schmid and Gero [234b]

indicated that the disputed band is strongly

overlapped by the 0 — 0 band of A1 !! —

X

! 2 of CS

in a variety of discharges and this level of CO

would appear to be illusory, and should not be

included among CO terms.

3.13. d

3At —

X

X S+ Transition (1620-1230 A) R

In a study of absorption spectra of CO in the

vacuum ultraviolet region, Tanaka, Jursa, and

LeBlanc [255] observed a weak progression of

single headed bands extending to high v', assumed

to correspond to the R heads of the transition.

At that time the upper state was thought to be

3 IC, and is now known to be 3 A *. The v' values

given in reference [255] need to be raised by one

unit. (See the discussion of v' numbering in the

Triplet d-a bands.) The band heads are listed

in table 21.

3.14. e

3 S

_ —a

3 n Herman System (5430-4270 A)

R

In a study of the d

3 Aj—

a

3 II Triplet bands,

Herman and Herman [96, 92] reported a new

progression of emission bands similar in appear- ance [red-degraded], but having more closely

spaced heads. These bands were attributed to a new system whose upper state was assumed to be

d (then thought to be 3 II) and the lower state

assumed to be a new triplet level lying near a

3 IL

Long ago Merton and Johnson [160] had observed

some of these bands, but had not identified them.

By using the absorption data of Herzberg and

Hugo [101] and that of Tanaka, Jursa, and LeBlanc [255], Barrow [12] has shown that the

Herman bands constitute the (+-0) progression

of the e

35T —

a

3 I+ transition (table 22). The v' numbering of Barrow should be raised by unity

[238a]. “It is anticipated that other bands of the

Herman system will probably be found at longer

wavelengths” [12].

3.15. E0

1 S+-X1 S+, I n-X1 s+, and Several Unidentified Transitions in the Vacuum UV

Region (1180-930 A)

In a discharge in CO at several mm pressure

Tschulanowsky and Gassilewitsch [261] excited a number of weak bands in the region 1200-930 A.

Included among the bands is the single band of the

E-X Hopfield-Birge transition. Most of the

bands are unclassified and are listed as such in

in table 35d. Several bands belong to a new

system labeled Eo! 2C — X'Z bv Tschulanowsky

[260] (see table 23). The (0-p") progression of

17
red-degraded bands has a system origin at 90866.2

cm-1

. The relative error is estimated to be 0.01

o to 0.03 A (or less than 3 cm-1

). The constant

v' value is uncertain and was assumed to be zero. A formula is obtained which fits the heads:

cr(0—y//

) =90869.45 — (2171.19 F'-14.28 v"2), giving constants which deviate considerably from

those of the ground state. On this basis the

reality of the E0 state is questioned.

For the most intense band at 1183.62 A, a value

of (B'-B") = —0.6882 cm-1 was obtained. Both

branches observed were of comparable intensity.

By using B" = 1.8702 cm-1 one obtains Bq = 1.182

cm-1 (which is given in table 47), r'~1.44 A, and

o-0 (0-0j =90866.2 cm-1 = 1100.52 A. This suggests a very weak bond and a state with a flat potential

curve. The B(, is not considered accurate, but a rough confirmation of its magnitude was obtained

from a partial analysis of two other bands. It is estimated that co e for the E0 state <(1000 cm-1 (comparable to the state of N2 ). Tschulanovsky [260] has also reported a group

of weak, overlapped red-degraded bands in the

region of 1100-1000 A which form a new ^-X

system. The measurements are not very reliable.

The best resolved band is the 0-1 at 1034.65 A,

which shows the P and R branches longer and more

intense than the Q. A value of (B'-B") =

—0.7659 cm-1 gives B' = 1.139 (see table 48)

using B'' = 1.9052 cm-1

. The calculated origin

of the 1 II—

X

1 2

+ system is at 98836 cm-1

. The

bands are given in table 24.

3.16. /

3 S+-*j3 n Transition (2980-2670 A) R

Schmid and Gero [233] have observed several

red-degraded bands (table 25) near the heads of

the 1-0 and 0-1 violet-degraded b-a Third Positive system. An especially strong band appeared

at 2670 A in a Geissler tube discharge (between

carbon electrodes) in neon, in the presence of very

little oxygen. Schmid and Gero [231] ascribed the

bands to a

3 2

+-a3 n transition. The upper state,

provisionally designated asjPS-1", was suspected as including high vibrational levels of the a'3 2+

state. The supposed confirmation of this assignment by Gero [78] was not fully accepted by Garg

[68], Gaydon [69], and Herzberg [99]. The work

of Herzberg and Hugo [101] on the a'-X transition implies that the Schmid and Gero bands

do not belong to the a'-a system.

Gero [78] has given the rotational analysis of

the two j-a bands which he labeled the 30-1 and

34-0 bands of the a'-a transition. Stepanov

[247] labeled these with v' increased by one unit.

For the a

3 II state in coupling case (a), 27 branches

are allowed. Relatively large triplet splitting

of the /

3 2

+ terms is indicated since most of these were observed. Spin splitting (cm-1

) is found

to be roughly independent of N:

2979.9 A 2669.7 A

f,-f2 0. 80 1. 05

F3 —

f

2 1 . 08 1. 43

(See p. 461 of ref. 80 for a correction to Gero’s

paper.) Perturbations are indicated near N=0

of the/ state, presumbably caused by 6

3 2+. Rotational constants for the / state are estimated

using the unperturbed levels with higher N

(table 49). The unperturbed term values of the

upper state vibrational levels are estimated to lie at 83744 and 85969 cm-1 (36 cm-1 has been added

to Gero’s figures [78] to account for revised a-X

data). Stepanov [247 [ obtained values close to

those of Gero which, when revised, would give

83755 and 85960 cm-1. The small B values (0.83 and 0.75 cm-1

) for

the / state terms imply either high vibrational

quantum states or a weakly bound electronic

state with large r e

. This rather peculiar structure should be re-examined experimentally.

3.17. I

1 s

--X1 S+ Transition (1520-1460 A) R

Three red-degraded bands consisting of a

single Q branch have been observed in absorption

[100] under high dispersion and correspond to the

forbidden I

1 S

--X1 S+ transition. Rough measurements of wavelength indicate a vibrational

frequency near 1000 cm-1

. Full details are not

yet available.

The F2- state had previously been known only

from its perturbation of the A1 !! state (see table

54a). A number of the perturbations caused by

the I state have been assembled by Schmid and

Gero [225, 234b], Ivovacs [135], and from more

o recent measurments of the B

1 2

+-A1 n Angstrom

bands b}^ Deutsch and Barrow [52]. These

authors all assumed that the v=0 level of the I state perturbed A1 !!, v=l. The above measure- ments [100] suggest that it is probably the v=l

level of the I state that is involved.

Earlier estimates of Be of about 1.48 cm-1

18
implied a value of a e of about 0.046 which is rather large for any state of CO. [But the b state has an a e of 0.042 or 0.033]. Deutsch and

Barrow [52], by assuming the value of ae as 0.018

cm-1 which is similar to other states having the

configuration 7r

3 a

2 7r*, have derived a term value

for the electronic state and vibrational and rotational constants. These values, adjusted by

raising their v values by one unit, are listed in

table 1. The state lies at about 65630 cm-1

.

A summary of the observed PD perturbations

is given below:

r(A] n) J T„-0 (FZ-)

l 1 35 66678

2 2 7 67704

3 4 40 69699

4 5 23 70667

5 7 44 72547

6 8 30 73459

8 11 34 76080

9 12 13 76915

11 15 16. 5 79360 (ref. 234b)

All data points but the last are those of Deutsch

and Barrow [52]. (Term values are in cm-1

).

3.18.

Unidentified Bands

A. Herman [95] has found two new groups of

triplets attributed to CO, which had earlier been

found in comets, using as source a 90-cm long

discharge tube with carbon electrodes, filled with xenon to a pressure of 10 mm of Hg. The two

groups of triplets have different structure. Group

(a) is red-degraded as is evident even under low

dispersion, group (b) has branches which look like

lines (as may be seen in fig. 1 of ref. 95). (See

table 35e.) No further details are given.

B. Johnson [118] has observed five doubleheaded red-degraded bands together with other

bands belonging to CO+. They are described as

similar to the A2 !!*—

X

2 D

+ comet tail bands, but

with different separation, and each head is not

a close doublet. These are given in table 35 j. C. Barbier [11] has observed 26 bands in the

night sky (5200-3200 A) which were attributed

to a new transition to the ground state of CO. The

upper state is at 21962 cm-1

, with u>'=2610 cm-1 and w ex'e =23.S cm-1

. Pearse[186] has questioned

this assignment since oj'»co''. The identity

of these bands as belonging to CO is highly questionable.

D. Huffman et al. [107] have observed nu- merous unclassified bands (table 35f) in their study

of the absorption coefficients of CO between

1000-600 A. These are in addition to many

previously observed Rydberg states, and other

bands seen by Tanaka [254] and Henning [91]. 3.19.

P, Q, R, S, T—X‘S+ Tanaka Systems

(800-630 A) R

Among numerous absorption bands which make

up several Rydberg series, Tanaka [254] observed

five new progressions with roughly constant

frequency difference. These progressions, representing transitions from the ground state to the P, Q, R, S, and T states, are listed in table 26.

Weissler et al. [270] have observed the P state

and the S (or T) state by photoionization. Kaneko

[124] has observed these in electron impact.

3.20.

Rydberg Series (940-630 A)

Rydberg series are of special interest because

their convergence limits give the ionization

potentials of the molecule. Absorption measure- ments have been reported of such series whose

convergence limits coincide with the three spectroscopically observed states of CO+. Recently,

series converging to what appears to be a new

state of CO+ have been observed [42]. The series

converging to the B, A, and X states of CO+ are

given, respectively, in tables 27, 28, and 29. The

observed Rydberg states of CO are most likely

x 2+ or

1 n, though no fine structure analyses have

yet confirmed the tentative assignments. Details

of their possible electronic structure have been

given in section 2. The spectroscopic observations

are reviewed below.

A number of bands which reportedly belong to Rydberg series have been observed under low

resolution by Henning [91] and Anand [2]. Uncertainties in the measurements make their series

limits unreliable. Henning [91] observed 22

bands in absorption, including 10 which formed

two progressions having nearly equal frequency

difference (~1550 cm-1

). The positions of these

broad bands are uncertain by ±50 cm-1

. Anand

[21 observed six headless bands in emission, and in

L J

• o the same spectral region (900-S50 A) saw a series

of four bands in absorption. Both series were

19
fitted by a Rydberg formula with a common limit

of 14.5 eV, which falls between the term values of

vibrational levels of CO+

, X2 2

+. Henning’s

bands are listed in table 35g. Anand’s are listed

in table 35h.

Tanaka [254], using a 3-m focal length

grazing incidence vacuum spectrograph, observed

numerous bands, including most of those reported

by Henning, as well as the F and G bands of

Hopfield and Birge [104]. A band at 783.1 A

(127,698 cm'1 ), reported to be very diffuse by

Henning, was seen under higher dispersion to have

three close heads, each being sharp and degraded

to the red. Tanaka found two sets of absorption

bands of equal intensity, one sharp and one

diffuse, each forming a Rydberg series labeled the

“j3” series and converging to a common limit at

630.12 A= 19.675 eV. The sharp series in the

region 700-620 A can be represented by the

formula

<7=158692-

R

(n-1.68)2 n = 5, 12 .

More recently, Huffman, Larrabee, and Tanaka

[107] have observed the n=4, 0-0 terms of the

“/3” sharp and diffuse Rydberg series in their

study of absorption coefficients of CO in the region

1000-600 A. (See also table 27.)

Another Rydberg series labeled “a” was found

[by Tanaka] to span the region 800-730 A. Its convergence limit was at 749.74 A= 16.536 eV.

The “a” series can be represented by the formula

<7=133380

(7i — 1.69) 2

’ n 5 . . 9.

The a/3” series includes transitions from the

Xx 2

+ state of CO to electronic states which con- verge to the B

2 2

+ state of CO+. A diffuse band

always appeared on the short wavelength side of

each sharp band. The “a” series converges to

the A2 n state of CO+. This latter series is strongly overlapped by other bands. Both “P”

and “a” series show vibrational structure which is close to that of the ionic states which are their

series limits. Tanaka [254] tentatively ascribed

the sharp and diffuse series to (

1 2

+)—

X

J 2

+ and

ClI) — A 2

+ transitions, respectively.

Takamine, Tanaka, and Iwata [253] have observed two Rydberg series converging to 884.73 A

and 868.13 A, respectively. These series are the

0-0 and 1-0 vibrational series whose convergence

limit is the lowest ionization potential of CO:

113029 + 32 cm-1 or 14.013 + 0.004 eV. This con- vergence limit is within the experimental error of

that derived from the limits of the “13” and “a”

series and the origin of the B-X system of CO+

. (The values in eV quoted here differ from those

originally given in ref. 253 because of a slight

difference in conversion factor.) The series has

been represented by a formula

<7=113029 —( n _ 1 ' 88y’ n =Q, . . 14.

3.21. B

2 S+ —

X

2S+ First Negative System of CO+

(3150-1800 A) R

The B

2 2+ —

X

2 2

+ First Negative system of

carbon, originally observed by Deslandres (see

also ref. 127a, p. 233), consists of an extensive

group of single-headed, red-degraded bands. The

upper state of this system is the highest lying

state of CO+ which has been observed spectroscopically, though a more energetic state has been

tentatively identified from electron impact and

photoionization measurements. Vibrational heads

of the B-X system are given in table 30, origins in

table 31. Rotational constants for the X2 2

+ and

B

2 2

+ states of CO+ are given in tables 50 and 52,

respectively.

A number of bands observed by Schniederjost

[ref. 127a, p. 213] were later correctly identified by

Jevons [116] as belonging to Deslandres’ system.

Additional bands of this system were reported by

Johnson [118] and Blackburn [26] who gave the

first vibrational assignments. This system was

extended to shorter wavelengths by Biskamp’s

report [24] of 22 new bands in an intense high

frequency discharge in helium containing a trace

of CO. The dispersion used was 8.8 A/mm [wavelengths are uncertain to ±0.05 A]. A formula

was fitted to the observed band heads:

<7=45651.5 + (1 695. 6F —24. 25z/2

) — (2196+'— 15.12+'2

)

Deviation from this formula of levels with v' =7

suggested [24] perturbation of this level as due to crossing of the 2 2 states. Early fine structure measurements on lower

vibrational levels of both states did not provide

reliable rotational constants because of overlapping lines and poor resolution. These include

studies by Coster, Brons, and Bulthuis [45] and

by Schmid [237]. The latter observed measurable

20
spin splitting only for high rotational quantum

number, typically about 30-34. The 3-5 band,

however, showed doubling (about 1.3 cm-1 width)

for P(23) and R(24).

The rotational analysis of the 0-0 band by

Schmid and Gero [222] established the ground

state as the common lower state of the Comet

Tail and First Negative bands.

Rao [202a] has made a comprehensive study

of the B-X system of CO+ under high resolution

which has provided the best values of molecular

constants of both states, band origins, rotational

constants, and spin doubling coefficients. [For

the latter see table 53.] Previously Woods [278]

had reported values of for the B and X

states which are about half those of Rao.

Rao [202a] has given the fine structure of the

0-0, 0-1, 0-2, 0-3, 0-4, 1-2, 1-3, 1-4, 1-5, 2-3,

2-4, 2-5, 2-6, 3-5, and 4-7 bands. Observations were made viewing a hollow cathode discharge

with a 21 -ft focal length grating spectrograph in

fourth order. Six branches are possible for a

2 2-2 2 transition, with each line of the P and R

branches split into a triplet by the selection rule

AJ=0, ±1. The satellite branches PQ12 and rQ2 i were very weak except at very low N. The

bands consist of a doublet P branch and a doublet

R branch, with doublet splitting resolved only for

higher N values.

3.22. A2 IIj—

X

2S+ Comet Tail System 8 of CO+ (7200-3080 A) R

Important characteristics of comet tail spectra

are bands of carbon compounds. Among these

are found the strongest bands of CO+

, A2 IIi—

X

2 2+

, which were first discovered in these celestial sources [189], and shortly thereafter weakly

produced in low pressure Geissler discharges in

CO by Fowler [64]. These bands which extend

from the UV through the visible region have two

double heads degraded to the red. Each band

shows eight branches (out of a possible 12), four

originating from each II doublet component.

The other four are not resolved because of unresolved spin splitting of the X2 S state. Rao

[202b] has found that previously used v

r numbering should be lowered by three units. Perturbations of levels A2 n,,?;=5 and 10 indicate crossing

by the ground state. Table 32 lists the observed

8 Earlier referred to as the Third Negative bands of carbon.

A-X band heads; precise origins are listed in

table 33. Rotational constants for the X and A

states of CO+ are given in tables 50 and 51,

respectively.

Merton and Johnson [160], Johnson [118], and

more recently Asundi [6] have observed bands of

this system in a discharge through helium with a very small partial pressure of CO (~10~4 mm).

Baldet [9] observed four heads of each of 40

o bands (in the region 6400-3080 A) produced by

electron bombardment of CO in the most extensive

single observation of this system. He drew a Fortrat parabola for the eight observed branches

of the band at 3997 A, but the more extensive

rotational analysis of many bands to which he

alluded has not been published.

Birge [21] showed that the First Negative and

Comet Tail bands had a common lower state. His vibrational assignments, as given in an early

review by Herzberg [97], were based on a fit to

all of Baldet’s data with neglect of a weak band

at 5281 A. This analysis did include three comparably weak bands at 6400 A, 5800 A, and 6000 A,

whose intensities were estimated as }2 by Baldet.

These were assigned as 0-0, 1-0, and 2-1 transitions. Rao [202b] did not see these weak

bands, nor have any B-A bands been observed

with v" values corresponding to the above

assignments. In addition, the above quantum

assignments gave abnormal Condon parabolas.

By lowering the v' assignments by three units and

omitting the four weak bands (listed in table

35i), these difficulties were eliminated [202b].

Much work has been devoted to fine structure

analysis of lower lying vibrational levels. Blackburn [25] reported seeing the Comet Tail bands

under high resolution, but gave no quantitative

data. Sometime later Coster, Brons, and Bulthuis [45] observed the fine structure of the 2-0,

3-0, 4-0, and 5-0 bands produced in a low pressure

discharge in flowing CO. Relative accuracy for

sharp lines was claimed to be 0.002 A. The

2 Ib state was found to be in Hund’s coupling

case (a) for low rotational quantum numbers.

Schmid and Gero [222] have given the fine structure of the 0-0, 1-0, 1-1, 2-1, 3-2, and 4-2

bands. Rotational analyses of many more bands

have been given by Bulthuis [34a, 35] who has

published details only of the 6-0 band and the

most intense branches of the 7-0, 8-1, 9-1, 10-1,

10-2, and 1 1-2 bands. Perturbations of the upper

level were found in the 10-1 and 10-2 bands.

21
The fine structure of the 0-2, 0-3, and 0-4

bands has been given by Rao [202b] who, in

addition, reduced previous data [34, 45, 222] to

evaluate rotational constants for the A2 !!* state. Accuracy of ±0.00025 cm-1

is claimed. The

following formula was obtained:

B' = 1.58940 — 0.01 942 (±±!), D;~6.60 X lO”6 cm-1 (est).

An average value of -117.5 cm-1 was derived

for the coupling constant A (which is negative

because the A state is inverted). A useful comparison of the branch designations used by

previous authors can be found in Rao’s paper

[202b].

3.23. B

2£+ —

A

2 n, Baldet- Johnson Intercombination System of CO+ (4240-3310 A) V

This system of double double-headed, violetdegraded bands has been much less extensively

studied than the other two known transitions for

CO+ . Spin splitting of the upper state is observable; for the lower state it is negligible.

Vibrational quantum numbering is based on the

work of Rao [202b]. Observed band heads are given in table 34.

Merton and Johnson [160] mentioned a number

of faint violet-degraded bands among their

A-X Comet Tail bands and similar in appearance.

Johnson [118] reported the band heads for the

0-1, 1-2, 0-0, 1-0, 2-0, and 3-0 transitions.

Several additional bands were found which have

not been identified (table 35j). Meanwhile,

Baldet [8] had previously reported the 0-1, 0-0,

and 1-0 transitions from electron bombardment

of low pressure CO.

Baldet [10] mentioned high dispersion measure- ments of the 0-1, 0-0, and 1-0 bands, but his fine

structure analysis has not been published. Bulthuis [34b] has given the rotational analysis of the

0-0 and 0-1 bands. These bands extended to

moderate J (~25), were very weak, and were

overlapped by the much stronger A-X Comet

Tail bands. The bands were observed in a hollow

cathode discharge. The spin splitting of the

B2 2 level was observable, and Bulthuis concluded

that the spin splitting in the B-X band for higher

J [34b] is due essentially to the B state. Rotational constants for each 2 n sublevel were obtained

which, when averaged, are in reasonable agreement with more recent results of Rao [202b].

For higher J the doublets P2-Qi2 and R1-Q21 are

clearly separated, but the doublets R12-Q2 and

P21-Q1 show only one component even for the

highest J values (~25).

Recently, Rao and Sarma [205] have summarized the work on all three observed transitions

for CO+ stressing the revision of v' numbering for

some B2 2-A2 IT Baldet-Johnson bands, and changes

in branch designation because earlier fine structure

analysis incorrectly labeled the A state as

2n r instead of inverted. Making use of the value

for the spin splitting constant 7 = 0.0192 for B2 Z,

v=0 and |y'-7"| obtained previously [202a], they

obtained values of 7 for the X state which are given in table 53. Blending of branches of the

intercombination bands prevented accurate determination of rotational constants.

4. Perturbations

A number of states of CO and CQ+ undergo

perturbations, most notably the A1 ]! and 6

3 2

+. The A state has the greatest number of perturbations; the b state suffers perhaps the most severe

disruptions in its rotational structure.

For CO, the identity of most perturbing states

is known. The existence of the PS" state, not

directty observed until recently, was revealed

from its interactions with the A1 ]! state. Supposed

predissociations of the A state [227,74], indicated

by intensity drops in the band fine structure, are not real. However, perturbations may occur

at these positions. Table 54 summarizes the

data on reported maximum perturbations, some

of which are uncertain.

This section which supplements table 54 is concerned only with the reported rotational perturbations. Multiplet splitting and A- doubling

are discussed in section 3 ; predissocations, a

special case of perturbations, are discussed in

section 5. 4.1. A: n State

a. v= 0 Stepanov [244] has determined the matrix ele- ments of interaction of 3 ZJ=N with (in inter22
mediate coupling between cases (a) and (b)), and

has applied the results to perturbations of A1 ]!, v=0, J=9, 12, 16. By using the data of Gero

[224a, 71], he obtained numerical values of the

matrix elements which were found to be functions

of J, and not constant as had been found by Bud6

and KovjIcs [33]. The almost linear increase with

J led to the conclusion that the A1 II state was in

intermediate coupling close to case (b), as had

been previously established (see sec. 3.1). Stepanov [245] has also mentioned the importance of

including the distorting affect of a third level at

the common point of intersection for low J. Coster and Brons [44] have also reported a

perturbation affecting all branches at J = 1 ; the

perturber is II or A since both A-components are

affected together, most probably 1 n since the

perturbation is already large at J=l. This

perturbing *11 state has not been observed directly.

In addition, all lines below J = 16 showed deviations of 6-10 cm-1

; most of these being due to

crossing by 3 2 levels. The 3 2 term value was

estimated at 64815 cm-1

; from the data of Herzberg and Hugo [101] e

3 2~, v=l was found at 64803

cm-1

. For high J (presumably >30) [44], a

3 II perturbation is mentioned.

Crawford [50] has studied the Zeeman effect in

the B-A Angstrom bands. [His fig. 5 shows the

Zeeman pattern for the P(l) and R(l) triplets of

the 0-0 band at 4511 A and also the asymmetry

of the Q doublets at low J for the 0-3 band at

5610 A.] He has tabulated a number of magnetically sensitive lines which show large Zeeman

patterns. These normally occur near points of

large rotational perturbations. For the 0-0 band

this includes Q(25) and probably others. (See

sec. 4.1, b to d for additional magnetically sensitive

lines.) Crawford described the appearance of the

0-0 B-A band as having weak and fragmentary

extra branches (see sec. 3.2; note particularly the

same difficulty of Jasse [115]).

Watson [268, 269] has reported additional faint

lines for the 0-0 B-A bands including the occur- rence of extra lines at the perturbations. Some of

the P, Q, and R lines at the perturbation of J ~28

become sharp doublets. The Zeeman pattern

indicated that the perturber was not a singlet state,

and was assumed to be d?Yli (now known to be d

3 A;).

Extra lines appear for J=8, 10, and 17.

The perturbed lines show large irregular Zeeman

patterns at medium and high J values. Neighboring lines are apparently insensitive to the

magnetic field. The perturbing state is assumed

to be case (a) 3 n. Watson [269] has given a table

of Zeeman patterns of the perturbed band lines in

the 0-0 B-A band.

b. v— 1 At J~0 Rosenthal and Jenkins [216] found a perturbation in all branches which they ascribed

to a

3 n, v=l. Schmid and Gero [225] believed,

however, that the perturbing state was *11, an

unobserved state. Coster and Brons [43] have found the following

perturbations in the 0-1 B-A band: R(26), P(26),

Q(23), Q(26), Q(29), and Q(35), with extra lines

corresponding to R(26) and Q(29). These seem

to include the a

/3 2+ perturbations as well as

1 2“

perturbations reported elsewhere [262,225]. The

observed deviations do not exceed 2 cm-1

, with

the largest deviations accompanied by intensity

reductions. Two additional 2 perturbations are found at Q(25j and Q(35) which may also be due

to the x 2” state. Read [209] has observed a perturbation at J ~26

in the 1-0 A-X band. Gero [74] reported a

3 2

- perturbation at J=44 in another A-X band.

Gero [71] has found small perturbations at small

J in v=\ with both A-components affected the same. Tschulanowsky and Stepanow [262] observed

perturbations in A-X bands, including the appear- ance of extra lines. In all cases the P and Q

branches were perturbed differently and perturbations result from interaction with the e

3 2~ state. For the 1-5 A-X band an extra line was incorrectly

attributed to Q(2S) and should be revised as

follows: Q(2S) =55571.07, Q(29) =55554.84, with

the extra line for J=29 at 55559.10 cm-1

. A x 2

term perturbs both J=26 and 35. An additional

perturbation at J=26 [44] is due to one component

of a

3 2 state. Crawford [50] has listed as magnetically sensitive

lines Q(23) and Q(24) in the 0-1 B-A band. Near

the perturbation at J~2S in this band Watson

[268,269] found that several P, Q, and R lines

appeared as doublets.

McCulloh [157a] reported a perturbation of the

lower state in the 0-1 B-A band for (' O ’. Perturbed lines include P(16), Q(13), Q(19), and

R(16). The perturbing state is s2 with B~1.13

cm-1

. (This is the isotopic analog to what Coster

and Brons [43] found.)

23
c. v—2

Rosenthal and Jenkins [216] observed perturbations at J=25, 29, and 33 in the 0-2 B-A band.

Extra lines appeared in the P and R branches for

J=25 and 33. Tschulanowsky and Stepanow

[262] saw the same perturbations in the A-X bands

including extra lines in the P branch for J=25 and

26. The perturbing state is e

3 2~, v=4 (from the

data of Herzberg and Hugo [101]). From perturbations [44], the term value of 67953 cm-1

is obtained.

Gero [73] observed doubling of the Q(7) line

in A-X bands. The perturber is 1 2~. Deutscb

and Barrow [52] observed this perturbation in the

B-A bands, and have tabulated the perturbations

caused by the PS" state for all vibrational levels

of the A1 !! state. Crawford [50] gives the following

magnetically sensitive lines in the 0-2 B-A band:

P(25), P(26), P(34), and P(35).

d. v=3

Rosenthal and Jenkins [216] reported perturbations at J=28, 31, and 34 in B-A bands. Coster

and Brons [44] showed that these levels are crossed

by the a' 3 2+ state. The estimated term value for

the perturber is 69459 cm-1

; a'3 2

+

, v= 12 is found

at 69602 cm-1 from the data of Herzberg and

Hugo [101]. Coster and Brons [44] found another

small perturbation of Q(38) which is due to the

1 S" state. Gero [74] found J=50 perturbed by the e

3 2~

state. Tschulanowsky and Stepanow [262] have

seen the 3 2 perturbation in the A-X bands. In

the 3-7 band extra lines are found for Q(27) and

Q(28). The extra line reported for Q(29) may

not be real, and cannot be assigned to J=28, 29, or 30. Crawford [50] includes the Q(28) line as magnetically sensitive in the 0-3 B-A bands.

Deutscb and Barrow [52] found P2- perturbing

J=40.

McCulloh [157a] found the maximum perturbation at Q (2 1) in the 0-3 B-A band of C

13016

. P(21) was unperturbed. Either the 3 2+ state or

is responsible for the perturbation; the proper

assignment can only be established from examination of high rotational levels.

e. fl=4

Coster and Brons [44] have found a perturbation

at J~31 in the 0-4 B-A band, the reality of which

is disputed by Gero [73]. Another perturbation

at J=34,37,—,is due to e

3 2

_

. The estimated

term value of 3 2 is 70878 cm-1

; from Herzberg

and Hugo [101], one obtains e

3 2~, v=7 at 70966

cm-1

. Gero [73, 71] has reported a

3 2+ perturbation

at J~0 and two others at J=23 and 27. The one

at J=23 is due to [52]. Asundi [5], in addition,

observed a very small perturbation for J=18.

Gero [73] has reviewed the work on a number of

these perturbations and gives the following identifications: J~0, 3 2

+

; J=23, 1 2~; J=37, 3 2“.

Additional perturbations include J=46, 3 2

+

; J=50, 3 n.

f. v=5

Gero [73] has referred to close crossing of 3 2

+ and 3 n states which overlap perturbations of A,

v=5. The first perturbation is at Q(30) in A-X

bands, and is due to 3 2

+. The last perturbation

of this pair of overlapping states is at R(35),

Q(36), and P(37), due to 3 n. A 1 2“ perturbation

is found at Q(44) [73, 52], and the onset of a

3 I~

perturbation at R(50).

g. v=6

Gero [73] has observed overlapping 3 n and 32

perturbations near the beads of A-X bands. An

additional perturbation was observed at Q(52).

Since the other branches were not followed to

such high quantum numbers the nature of the

perturbing state could not be determined with

certainty, and was assumed by Gero to be 3 IT. Several additional perturbations at J=29, 30 have

also been found [73, 52].

Onaka [182] later unraveled the structure near

the bead in bis observations of the 6-13 and

6-14 A-X bands. Details of the 6-14 band are not given. A perturbation near J=0 which acts on all branches, indicates a n or A perturber with

B» larger than that of the A state. (A similar

perturbation has been found of A, v=0 by Coster

and Brons [44], indicating the possibility of a common state perturbing both the 0 and 6 levels.)

Several extra lines are observed for y=6, which

include P(7), R(7), Q(ll), P(13),Q(13), and Q(16).

The perturbations observed are: J'=7~S, 11,

14, 16 in Q; and J'~0, all branches.

h. v=7

Read [209] has observed perturbations of R(25),

Q(27), and P(27) in the 7-1 A-X band. Another

24
perturbation at J=29 was designated as 3 S“ by

Gero [73]. In addition, Gero found a

3 2+ perturbation at J=26, and a

3 n perturbation at

J=39. Gero [74] mentions a sudden intensity

drop from R(46) to It (47) in the 7-16 A-X band

with no simultaneous line displacement.

i. 0=8

Gero [73] found the following perturbations in

A-X bands: J=18, 3 2+; J=27, 3 n; J=34 [52],

! S

_

. Gero [74] mentions the following sudden

intensity drops (no line displacement)

8-16, A-X R(35) »11(36)

8-

17, A-X R(35) »R(37) ; R(36) over- lapped.

j. v—9

Gero [73] found a perturbation at J=13.

(See also ref. 52.) At J=37, a

3 2

+ perturbation

is expected [74]. Gero [74] lists the following

intensity drops unaccompanied by line displacements:

A-X

9-

17, P(22) P(23); R branch overlapped

9-18, P(22) » P(23) ; R(19) »R(22);

R(20), R(21) overlapped; Q(27) )>)>

Q(28); P(28) > P(29)

9-19, P(22)> P(23);R(19) >> R(21) ; R(20)

overlapped

9-20, P(23) and R branch overlapped; Q (27)

»Q(28).

k. v=10

Gero [73] has studied numerous perturbations

of the Ax n state in the A-X bands. It is determined that for 0

' = 10, at J=16 and 18, there are perturbations of P(17) and Q(18) by 3 2~. The

strongest perturbations are overlapped by the

3 2

+ state. The branch lines, however, are of nor- mal intensity beyond the perturbed level and can

be followed to J=34. At J=32 there is a

3 n

perturbation.

l . 0=11

Gero [74] found a perturbation of J=16 by 3 n

and 1 2~.

m. 0=12

Gero [74] found a perturbation of J=24 by 3 2

+.

n. i>=13

Gero [74] has analyzed lines only up to J=15.

He indicates a probable 3 n perturbation near that

limit. For the bands with 0 = 11 , 12, 13 only one band was observed, so that localizing the perturbations is less certain than for the other bands.

4.2. E

x n State

In the 0-0 E-X band Tilford et al., [257] observed a perturbation at J' =31 in both R(30) and

P(32). These lines appear as doublets, and, in

addition, are anomalously more intense than their

neighbors. A state of type x 2

+ is the suspected

perturber.

4.3. a

3 YL State

Beer [16] has studied the perturbations of the a

3 n, 0=4 level in the 0-4 and 1-4 bands of the

6

3 2+—

a

3 n Third Positive bands. Eight observed

crossing points are attributed to a perturbing 3 2

+ term for which B„=1.31 cm-1 was estimated.

The perturbing state, which lies at an energy of

55380 cm-1 above the reference level Xx 2

+

, 0 =0, J=0, has been identified as a'3Z

+

[235]. From

previous b-a studies by Dieke and Mauchly [54],

and Gero [75] it is shown that the a

3 n, 0=0 , 1, 2,

and 3 terms are regular (unperturbed). Dieke

and Mauchly [54] tried an analysis of the 0-4

Third Positive band, but could only conclude that

strong perturbations were probably present. Beer

found no perturbations of v" =5 from the. 0-5 and

1-5 bands. [In these bands the 6

3 2, 0=0 and 1 levels are subject to strong and consecutive perturbations [54, 75]. (See sec. 4.6.)

The eight perturbations are listed in table 54c.

Numerous extra lines appear in the 0-4 and 1-4

bands.

Since the a

3 n state is no longer in coupling case

(a) for medium values of rotational quantum

number [50], one can allow for violation of the

selection rule for perturbations A£2=0, ±1. In

fact, in two places, the perturbations occur with

Aft=2. The absence of a perturbation at the

ninth crossing point where Aft=3 results from the

rules for intermediate coupling. From the perturbations, B~1.31 cm-1 and o- 0 ~55,3SO cm-1 (above X) are calculated for the perturbing state. These values correspond closely to those of the

a'3 2+, 0=0 level. The 0-6 and 1-6 bands should

show the onset of perturbations sooner, but these

were not analyzed due to insufficient light inten25
sitj7

. The lowest perturber level of a

/3 2

+ is most

certainly y=0, since a

3 II, y=0, 1, 2, and 3 show

no perturbation. The Third Positive 0-6 and 1-6

bands should show perturbations at J ~47. These

have not yet been observed.

Beer’s estimates of the constants for the a

state agree fairly well with the accurate determinations by Herzberg and Hugo [101].

4.4 d

3 A t State

Gero and Szabo [S2] have reported perturbations

in all components of the y=6 term of the d state

in the d

3A*—

a

3 II Triplet bands at J=8, J = 13-14,

and J = 14-15.

4.5. /

3S+ State

In a study of the 2980 A and 2670 A bands of

the /

3 2

+-^>a3 II transition, Gero [78] observed

perturbations of the upper levels by the y=0 and

y=l levels of the 6

3 2

+ state. The perturbations

are seen in the 2670 A band at N=13 in the

p

$i2 (N), P2 , R2 , and RQ3z branches. The N= 13

level for the other band also seems perturbed.

A plot F of versus N indicates dependence 4(N + |) _ P

on Nfor small N] hence, a perturbation at 0 by

another 32

+ term. (See table 54e.) These bands

had at one time been thought to originate from

high vibrational levels of the a'3 2

+ state.

4.6. &

3 £+ State

Dieke and Mauchly [54] have indicated that

numerous large perturbations of the upper state

of the 6

3 2

+ —a

s n Third Positive bands cause the

characteristic intensity fluctuations previously

observed by Wolter [277]. The perturbations were ascribed to successive high vibrational levels

of the 3 2 perturber, presumably a'3 2

+. These

are mixed with levels of the state

/

3 2

+. The first

large perturbation in y=0 is at N= 19, hence the

head region is not affected. However, there is no

apparent regularity of lines in the middle of the

bands. The perturbations result in clustering of

lines in some places and gaps in others. Similar

effects which are expected for lower N values near

the head region for bands with y' = l would make

the v'=l progression appear to belong to another

system. In the y' =0 progression for v" —0 to 4,

the last few lines in all branches showed perturbations of increasing magnitude with increasing N

values, and the lines did not return to their regular

sequence after perturbation. This indicates a

II or A perturber. [Fig. 2 of ref. 54 shows the , irregularly spaced triplets.] Deviations of a single I perturbation exceed 50 cm-1

[53].

Gero [72] determined numerous perturbations

whose spacing decreased with increasing N.

Gero [75] observed the disrupted structure of the i

1-

0 b-a band. Perturbations made it impossible

to isolate branches below N=5. Often lines did : not follow in order of the quantum assignments.

Additional perturbations were found for 3 2 levels

N= 17, 25, 30, 34, and 40. The perturber is the

same 3 2 state which affects the 6

3 2

+

, y=0 level.

The perturber would appear to be the/3 2

+ state

[78, 247, 101], incorrectly identified previously as high vibrational levels of the a'3 2+ state. (See

further details on the f-a transition in the section

on electronic transitions.) The term values of J the perturbing levels lie at 83744 cm-1 and : 85969 cm-1

.

4.7. A2 nz State of CO+

a. v=5

The A2 n1/2 (y=5) level is perturbed by the X2 2

(y=14) level [45]. In the 5-0, ATli^—

X

2 2

+ Comet

Tail band, the perturbations include a number of

successive extra lines in both the Qi and Q2 branches (most of them being displaced towards

higher frequency, one displaced towards lower

frequency). The perturbing state is 2. The

perturbations occur for a large number of lines,

because very similar B„ values for both interacting

levels cause both sets of levels to stay close together.

At J=14| is the maximum perturbation of one A-component of the n1/2 level by the 2 level with

J =N— at J=22|, the other A-component is perturbed by 2, J=N+ |; the n3 / 2 level is unperturbed. The perturbing 2 level lies between

IIi /2 and n3/2 for low J. (See fig. 4 of ref. 45.)

This, together with the fact that the peak perturbations lie so far apart, indicates a relatively

slight angle between the potential curves of the

interacting fl and 2 levels.

For small J, the n3/2 level is probably not

perturbed. From extrapolation of data for the

2-

0, 3-0, and 4-0 bands, any displacement would

not exceed several tenths of a cm-1

. Both

A-components of the n level are displacd about

2 cm-1 for low J. The perturber is X2 2

+. From

the two crossing points Xc= i 4 Ap=5, a value of

Bs—1.7 cm-1

is determined which is in fair

agreement with the value for X2 2, y=14. The

26
extra lines are due to the X2 2(0=14) —X2 2 (v = 0)

transition. It seemed strange that perturbations were not also observed in the other bands considered here (2-0, 3-0, and 4-0). This may be

explained by the fact that the observed crossing

of II and 2 here indicates that the potential curves separate rapidly from one another, and

have different r e

. The 2 levels would appear to

fall between the II levels for low v and low J so that a crossing with n3/2 is not expected till very

high J. In fact, there appears to be a perturbation of n3/2 — 2(4-0) for J>30i /2 . (Probably due

to X, v— 1 0 affecting the low energy A-component)

.

b. v~ 10

In the 10-1 and 10-2 A2 n-X2 2+ Comet-Tail

bands, Bulthuis [35] found a perturbation of the

R12 Qh and Qi2 Ph branches. The perturbed level

is A2 n1/2 , 0 = 10. From a knowledge of they' =9

and 1 1 levels the unperturbed branches of A2 ni /2 — X2 2

+ for v' — \0 can be accurately calculated by

addition of the mean values of A2 n1/2 —

A

2 n3/2 differences of these two known levels to

the measured branches of A2 n3/2 —

X

2 2

+ (z/ = 10).

The O—C (observed— calculated) differences for

the lines are the energy shifts due to the perturbation. The shifts are small (about 3 cm-1 at most)

(see fig. 3 of ref. 35) and include J=3| to 21 j, the

range observed. This can be understood from

the results of Ittmarm’s [112] theory where the

matrix elements determining the magnitude of

the shifts are small for small J. The perturbations occur for numerous J values

as can be seen from figure 3 of reference 35.

Here, for 0=10, the crossing of perturbing levels occur at very low J values. Hence, the perturbation is observed for many J values because for

small J the two perturbing potential energy curves

are more parallel than in the case of high J, since

the energy differences for the same AJ increases

with J. This follows also because the interacting

levels have very similar B values.

All perturbing energies are negative (O —C) as seen from figure 3 of reference 35; hence, the

perturbing level lies entirely above the perturbed

A2 IIi /2 level. By making use of Biskamp’s [24]

band head formula, the perturber is found to be

X2 2

+

, 0=18. Extrapolating from figure 3 of

reference 35, for J = 0, the ratio of perturbations

in the two A-components is 2.5:3. 6. This ratio can be used to calculate the energies of the two

perturbing 2 II —2 2 levels using Ittmann’s [112]

formulas. See figure 4 of reference 35 for energy

curves of the perturbing levels.

The details of the perturbations are given in

table 54g.

5. Dissociation Energies, Predissociations, and Convergence Limits

5.1 Dissociation Energy of CO

After a long history of controversy, the dissociation energy of carbon monoxide D°(CO),

having a value of 89460 cm-1 or 11.091 eV [28], can now be regarded as generally accepted, though

the triplet levels of the atomic dissociation

products are not known. From the noncrossing

rule the products would be C(3P0 ) +0(3 P2), but

this has not been established as yet. Since the

X1 2

+ state of CO dissociates to ground state

products [69, 56] it is possible to make a unique

correlation between a number of excited molecular

states and their dissociation products (table 1).

Reviews concerned with the dissociation energy

of CO have favored a variety of values. (Refs.

98, 235, 70, 87, 84, 69, 151, 88, 28, 56 and others.)

The work of Gaydon [69], Douglas and Miller

[56], Brewer et al. [27], and Brewer and Searcy [28]

has resolved this question in favor of the “high”

value, with several minor inconsistencies still to be ironed out.

In his review a decade ago, Gaydon [69] favored

a value of D° near 11.1 eV based on application

of the noncrossing rule and an exhaustive comparison of the evidence from spectroscopy, electron

impact, photoionization, and determinations of

the heat of sublimation of carbon L(C). Since

then, Douglas and Miller [56] have made high

dispersion observations (0.23 to 2.5A/mm) of the

B^^A1 !! Angstrom bands (including those of

isotope C

130

16) and A1 II-X1 2

+ Fourth Positive

bands. They also reviewed the data on suspected

predissociations of the A1 !! state concluding that

none of these were real. This laid to rest predissociation data in support of values of D° lower

than 11.1 eV and confirmed the value obtained

from predissociations of the B! 2

+ and 6

3 2

+ states. The results [56] also denied the existence of any

appreciable maxima of the potentials in CO,

though Hagstrum [87] had claimed one of about

0.2 eV at r]>2.9A for the a

,3 2

+ state. Brewer and Searcy [28] list as best value for

D°(CO) S9460± 150 enroll .091 ±0.019 eV.

794-908—06 3 27
The probable error is ±92 cm-1

. These uncertainties are based on the value 89595 ±30

cm-1 obtained by Douglas and M0ller [56] as an

upper limit assuming the dissociation products

are C(3P0) +O(3 P2). This was in close agreement

with the value 89620 ±50 cm-1 obtained earlier

[72,224] from a limiting curve of dissociation.

The lower limit is 89325 cm-1

if the dissociation

products are C(3P2 )±O(3P0 ). The mean of these

extreme values is that given by Brewer and

Searcy. D° is defined as the energy difference

between the ground electronic state of the molecule

and the energy of the atomic dissociation products

in their ground states (e.g., C(3P0)+O(3P2)). Although it is most likely that the dissociation products are in their ground states, the mean value given

by Brewer and Searcy is listed here as best value in

order to underline the uncertainty. For thermodynamic calculations, however, ground state

products are assumed to correlate with the observed predissociation. Thus Evans and Wagman

[61] have used 89595 cm-1 for D°(CO) to be

consistent with previous usage.

Recent electron impact work [88, 62] and shock

wave experiments [259, 132] also support a value

of D°(CO) of about 11 eV.

The only spectroscopic evidence supporting a lower value of D° is the fact of missing bands of

6

3 2

+ —

3 n with v'=2, discussed by Gaydon [69]

and Barrow et al., [13] which suggests D°< 10.94

eV. This missing structure is presently an anomaly which requires further consideration. The

reported observation of the 2-0 B-X band [255]

which lies above the dissociation limit is somewhat

uncertain, though the v' =2 level could be populated by inverse predissociation. Only the early

work of Angstrom and Thalen (in 1875) [see footnote in ref. 23] mentions a band for B, v=2\ but

this too is uncertain.

5.2. Predissociations and Convergence Limits

The most precise determination of D°(CO) has

been obtained from the data on predissociations of

B*2+

, ^=0,1 and 6

3 2

+

, v=0,l by the common state a

/3 2

+ (or j

/’3 2

+

) [72, 56]. In these instances, where

the rotational structure is broken off for at least

two successive vibrational levels [235], the actual

dissociation limit lies close to the predissociation

limit. Furthermore, the state causing the predissociations must be bound. Glockler [84] is therefore incorrect in his assertion that a repulsive

state predissociates the B state.

Termination of vibrational structure in other

states may indicate predissociation [235, 221] by a

state or states as yet unspecified, and possibly

repulsive. Such is the case for the states C^4-

, c

3 2

+

, E, and F, for which only «=0 or 1 is known.

A dissociation limit may be obtained from con- vergence of a state’s vibrational structure or from

a Birge-Sponer extrapolation (which should only

be made with caution for excited states). In this

regard, the a' and F states raise the most interesting questions (sec. 5.2e, f). Discussion of the known and suspected predissociations, and convergence limits follows.

A summary of the predissociations is given in

table 55.

a. Predissociation of the B1 2+ state

Coster and Brons [43, 44] reported a sudden

drop in intensity by a factor of two for the lines

P(39), Q(38) and R(37) of the 0-1 B

1 2+-A1 n

Angstrom band. A similar intensity drop was

observed by Read [209] in the 0-0 B-X band.

This effect was attributed to predissociation of

B^4

*, zj=0, J=38 by some triplet state whose

dissociation limit was near the predissociation

limit. A forbidden transition was indicated be- cause the rotational structure was weakened, not

terminated.

Hulthen [108] observed lines of the 1-1 B-A

band up to J' = 14 in the P branch and J' = 17 in

the Q and R branches, but made no mention of

intensity irregularities. Schmid and Gero [224]

reported a sudden intensity drop for J'> 18 in the

1-0 and 1-1 B-A bands, i.e., 1-0, Ptl8)»P(19);

Q(17) > >Q(18)]. A dissociation limit of 89620

±47 cm-1 was obtained [74,226].

Douglas and Mqller [56] reexamined the B-A

Angstrom bands and confirmed these predissociations. In addition, they established these predissociations for C

130

16 at B

J 2

+

, w=0, between

J=39 and 40, and v=\, between J=19 and 20.

(A portion of the 0-2 band of C

13016 showing the

weakening of the lines is reproduced in fig. 1 of

ref. 56.)

b. Predissociation of the b3 2+ state A convergence limit for the perturbations of

&

3 2

+

, y=0 is found for 55<A^<56, and considered

by Dieke and Mauchly [54] to be a result of predissociation. It is not possible to detect the

predissociation by a sudden intensity drop because

28
the numerous perturbations already confuse the

intensity distribution of the lines. Indirect evidence supporting the predissociation is that the

analysis of Dieke and Mauchly [54] stops at

N' = 55 . Of all the branches observed by them

23 of the strongest 36 break off just at N' = 55:

Q(55) twelve times, P(56) five times, and 11(54)

six times. No line was found for N'^>55.

It is assumed that the cause of this predissociation as well as that of B^* is the same—Ike

fl,+ state (or a'3 2

+ state). (Ref. 72, fig. 2 is obtained from the method of Buttenbander and

Herzberg.)

Brons [30] confirmed the predissociation of

6

3 2, v=0, J=55 in his observation of an intensity

drop in the 0-1 Third Positive band. The sus- pected predissociation [54,226] is found by Gero

[75] in the 1-0 6

3 S

+ —

a

3 n Third Positive band at

N~43. The branch lines R1 i2(3 (41), Qi, 2,s(42), and Pi, 2 , 3 (43) all have regular intensity; the next

lines are unobserved.

The 1-0 Third Positive band reported by

Schmid and Gero [226] at 2673 A [it should be

2665 A] shows successive perturbations [clusters

of lines looking like triplets] converging to a limit

at 2628.3 A (38036.7 cm-1

), which seems to be the

same predissociation limit as that for the B state

in the Angstrom bands [72]. If it is assumed

that the perturbations are caused by successively

closer terms blending into a continuum, then a

transition from this lower limit to the a

3 n state

corresponds to an energy of 38036.7 cm-1 (v=0)

which corresponds to Q(43). (The limit at

38036.7 cm-1 corresponds to Q(N=43). See also

ref. 75.)

c. Predissociation of the C'S+ state

Schmid and Gero [224b, 221 ] have interpreted

as due to predissociation a sudden intensity drop

at J=29 in band lines of the C

1 2

+ —

A

1 II Herzberg

bands originating from level v' = 0. This limit

is about 3900 cm-1 or 0.48 eV above the limit

obtained from the Bx 2+ predissociation, and

hence provides only an upper limit to the dissociation energy. The C

! 2

+ state lies below c

3 2 ; for neither state are there bands with v'^>l. This

would appear to confirm the reality of the predissociation. (See ref. 235.) The C-X, 1-0

band has been observed in absorption [276] and

shows no evidence of predissociation. However,

predissociation is difficult to detect in absorption.

Gero [74] included in his tabulation of suspected

predissociations the breaking off in the C state of

rotational structure between 93486-93608 cm-1 (average 93552 cm-1

). What has proved to be an

incorrect assignment of C(’S) +0 (

J D) at 93335

cm-1 above X led Gero to conclude that a repulsive

state caused the predissociation because of the

217 cm-1 difference between the atomic product

and predissociation limits (i.e., kinetic energy of

the dissociation products).

d. Suspected Predissociation of the c

3 2+ state Schmid [ 221 ] reported a possible predissociation

of the c

3 2+ state at 11.5 eV because only the

v'=0 progression is known for the c

3 2

+—a

3 II 3

A

bands, and the upper level lies close to the C

1 2

+

, v=0 level which undergoes predissociation. A

further reason for suspecting predissociation [77]

is that the few observed bands of the c

3 2

+ —a

3 n

3A system are short and drop off in intensity

rather abruptly about 10 A from the head, while

similar exposures of other bands stretch for 50

to 100 A. (Jmax in this case, assuming T=300

°K and 104 °K, gives ~7 and~13, respectively.)

Because of overlapping of the 3A and A1 n—

X

! 2

Fourth Positive bands, it is not possible to determine the exact rotational quantum number of the

intensity drop in any branch. However, from the

predissociation limit of C

1 2

+ at 93554 cm-1

, the

position of the c

3 2+ state at 92076 cm-1

, and

B0 [a3 n]= 1.9563 cm-1

, the first weakened level is found to be at J~27.

e. Convergence Limit of the a'3 2+ state The a

, 3 2

+ state is known up to v—23 from

a' —X bands [ 101 ]. Perturbations of A1 !! identify a', v =10 to 26; perturbations of 6

3 2

+ have been identified as due to a', v=2>2 to 41

[234a]. Some uncertainty exists [69,99] in the

identity of the higher lying levels which are probably confused with terms of the /

3 2+ state,

about which little is known. Rotational constants

for these levels go to zero at a term value of about

89600 cm-1 above X [234a], which corresponds to

the known dissociation limit.

Gaydon and Penney [70] have applied the noncrossing rule to the o/3 2

+ state and concluded that

this state must go to ground state atoms. If not,

then the unlikely possibility arises that two 3 2

+

states dissociating to ground state atoms must

lie completely below the a' state (and have been

29
unobserved to date). The regularity of the a

state’s vibrational levels (up to v=23) does not

indicate avoidance of crossing.

Two bands earlier believed to originate in high

vibrational levels of the a

/3 2 state most probably

originate from the otherwise unobserved /

3 2

+

state [78]. Some interaction to avoid crossing by

these two 3 2

+ states appears unavoidable. Perturbations of the 6

3 2

+ attributed to the a' and /

states may arise from their joint interaction (e.g.,

perturbation of three states).

f. Convergence Limit of F(‘2+) state TheF(1 S+

) state with co e =2112 cm-1 and extraordinarily large co ex e =198 cm-1 probably has the

flattest potential curve and smallest dissociation

energy of all stable states of CO [224b, 105].

(But see the footnote to F state in table 1.) A

linear extrapolation gives a dissociation energy of

0.5 to 0.6 eV. Gaydon cautions against BirgeSponer extrapolations for excited states, especially

when some may have potential maxima. However, the rather large value of w exe for the F state

implies rapid convergence of the vibrational levels.

If the dissociation products are known for F,

then D° for the X state can be obtained without

knowledge of predissociations. Schmid and Gero

[224b] correlated this dissociation limit at ^12.9

eV with C(1 S) +0(1 D), which led to a low value

of D°.

The details of the F state have not been published, and its identity as *11 is uncertain

[69, 99, 147]. It was thought to be definitely

singlet [224b] because of the high intensity of the

F<—

X

J S transition so that it would dissociate

into either two triplet or two singlet atoms.

Howell [105] rules out the former [but doesn’t

say why] and offers most probably products as C(J D) fi-O^D). This would mean a dissociation

energy of the F state of about 4.4eV which appears

much too high. On this basis he obtained

D°(X) as 9.6 eV from the energy difference

[C(1 D) +0(1 D)]-[C(3P) + 0(3P)]=3.3eV. However, using D° as 11.09 eV and the F state dissociation limit as 12.9 eV it follows that the dissociation products are most likely C(3 P) +0(1 D),

indicating a triplet molecular state. This could

imply a dissociation energy of the F state of

about 0.9 eV. Lefebvre-Brion et al., [147] predict

the F state to be 1 S

+.

The branches of a

3 2~ — ] 2

+ transition are

P P, PQ,

R

Q, and RR which under low resolution

may look like the P, Q, and R branches of a

1 H— transition. The intensity of the F —

X

transition suggests that probably a singlet state

mixes with the F state (if triplet) to make strong an otherwise forbidden transition. The identity

of the F state remains uncertain.

5.3. Dissociation Energy of CO+

, Ionization

Potentials and Rydberg Series

The dissociation energies of the ground states

of CO and CO+ are related as follows:

D°(CO+) =D°(CO) +IP(C) —IP(CO)

.

Substitution of known values into the right hand

side gives

D°(CO+) = l 1.091 + 11. 267- 14.013

D°(CO+) =8.345 eV

IP(C) was taken from Moore [166]; IP(CO) was

obtained from the Rydberg series limit of Takamine et al. [253], and D°(CO) was taken from the

predissociation limit in B1 ^of CO [28]. (The

conversion factor used is given in appendix B.)

If the dissociation products of the ionic molecule

are known, then the dissociation energies of the

various states can be given unequivocally.

Gaydon [69] has given a succinct review of

earlier estimates for the dissociation energies of

the three known states of CO+

, based mostly on

Birge-Sponer extrapolations of the vibrational

levels of these states and the noncrossing rule.

These arguments will be mentioned briefly for

the sake of completeness. For the ground state

of CO+

, a linear extrapolation by Biskamp [24]

beyond y=13 gave D~9.9 eV, which Ga}T don

and Penney [70] believed was not accurate because

of its length. The vibrational levels of the A

state extrapolate beyond v=14 to ~9.2 eV [70].

The levels of the B state beyond v=10 extrapolate

to about 9.3 eV above the X state [24,70].

There is no direct evidence as to the + or —

symmetry of the X and B states [70]. By assuming that they are both 2

+ states [99, 69], it must

necessarily be concluded that the X and B states

have different dissociation limits to avoid crossing.

The lowest dissociation products of CO+ are

30
C+(2 P)±0(3 P) which can form 2 2+,

2 2“(2), 2 n(2)

and others. Both the X2 Z

+ and A2 n* states give

ground state atomic products. The B2 2

+ state

dissociates to C+

(

2P) +0('D). Hence an un- ambiguous energy level diagram can be drawn for

the observed states of CO+ (ref. 69, pp. 186-7).

Dx (CO+

) =8.345 eV, DA =5.S15 eV, DB =4.654

eV, using 0(1 D)-0(3P) = 15867.7 cnr‘= 1.967 eV

[166]. These values are obtained from the ionization potentials of CO using data from Rydberg

series [253, 254] and electronic transitions in CO+

[202b, 202a, 205]. The values given in section 2

are repeated for convenience: 14.013 eV, 16.544

eV, 19.671 eV.

There have been numerous other determinations

of the ionization potentials of CO [129] mostly

from electron impact and photoionization [65,

151, 267]. Wilkinson’s review [275] compares the

uncertainties in the three methods.

5.4. Dissociation Energy of C02+

C02+ has not been observed spectroscopically

but has been observed in electron impact experiments [263, 55] at 41.8 eV and 45.9 eV above the

ground state of CO. Vaughen [263] has shown

that the preferred dissociation products of C02+ should be C2+ ±0 corresponding to a bound state

with dissociation energy of 4.8 eV. This value is close to that of the isolectronic molecule BeO

(4.4 eV according to Gaydon [69]; Herzberg [99]

gives 3.9 eV). Hurley and Maslen [111] have

developed approximate expressions for the potential energy curve for the lowest bound state of

C02+ which use a scale factor <1 multiplying the curve for CO,X. Dorman and Morrison [55] have

assumed slightly larger r e than for CO,X and

have sketched the curve schematically. No

further information is available on C02+

.

6. Vibration-Rotation Spectrum of CO

The vibration-rotation bands of CO lie at wavelengths shorter than 5 n. Observed bands of the

Ay=l sequence include those with v'<5 ; the

Av=2 sequence includes those with v'<7. Overtone bands 3-0 and 4-0 have also been observed

[102, 191]. Table 56 lists the observed band origins. Rotational constants derived from infrared

measurements, including some isotopic data, are included in table 36.

Recently it has been proposed [203a] that calculated positions of lines of the 1-0 and 2-0 bands

based on measurements by Rank et al. [197, 198,

196] and Plyler et al. [192-3, 190, 194], be adopted

as secondary standard wavelengths in the infrared

region. (The relative accuracy of the standards is ±0.0003 cm-1

; absolute accuracy is ±0.002 cm-1

[203b, 196].) From these data, Rank et al. [197,

198] have derived molecular and rotational constants. Benedict [17] has recalculated slightly

different values of molecular constants for the

ground electronic state (table 1) which are consistent with both the infrared measurements and

the data from electronic spectra. Analysis of

new measurements on the fundamental band [17,

63] to J values up to at least 70 will provide a good

test of the uncertainty in these constants.

6.1. Av=l Sequence

The earliest observations of CO vibration-rotation bands were by Lowry [155] and Snow and

Rideal [241]. Fine structure of the fundamental

and overtone bands was first resolved b}r Whitcomb and Lagemann [272], and for the isotopic

fundamental (C13 0

16) by Lagemann et al., [139].

Mills and Thompson [162] have since measured

the fundamental bands of C

13016 and C12018 (with

line positions good to ±0.03 cm-1

). Plyler et al. [193], in addition to 1-0, measured some lines of

the 2- 1 band of these isotopes.

Benedict et al., [18] have measured the fundamental bands of the isotopic molecules C

13O10

, C

13018

, and C

12018 relative to the 1-0 band of

C

120

16

, in addition to making measurements on the

2-1 band of C

12 0

16

. (Individual line measure- ments were reproducible to ±0.02 cm-1

; isotopic

line positions relative to C

12016 are accurate to

±0.01 cm-1 and are in close agreement with positions calculated from the molecular constants of

Goldberg and Muller [85].)

Laser action on P branch lines in the 6-5, 7-6,

8-7, 9-8, and 10-9 vibrational bands has been

reported by Patel and Kerl [185]. (See also re- ferences listed therein.)

6.2. Overtone Sequence and other Overtone

Bands

Plyler et al., [191] have observed lines of the

2-0, 3-1, 4-2, and 5-3 bands in the overtone
region. Isotope shifts for the origin of the 2-0

bands were reported for C

12016 —

C

130

16 and C120

16 —C

120

18

. Goldberg and Muller [85] identified

nearly 300 lines of CO between 2.29 —2.50m in the

spectrum of the solar limb to J values above 70.

The overtone sequence included 2-0 to 7-5, with

measured wavelengths referred to the center of

the solar disk. Derived molecular constants are

in close agreement with the current best values.

(See refs. 161, 165 for a listing of solar infrared

CO lines.) Plyler et al., [190] have measured the

same sequence. Transitions till 11-9 were seen,

but overlapping allowed precision measurements

only on 2-0, 3-1, and 4-2 to J values near 70.

Recently, St. Pierre [273, 218] has remeasured

lines of the 2-0, 3-1, and 4-2 bands with improved

precision. Rank [197] has determined the 3-0

band origin from interferometric measurement of

the R(6) line and use of precisely determined

molecular constants.

Herzberg and Rao [102] have photographed the

4-0 band with wavelengths of unblended lines

having relative accuracy of ±0.01 cm-1

, and

absolute accuracy of 0.03 cm-1

.

7. Rotational Spectrum of CO (Microwave and Far Infrared)

The pure rotational spectrum of CO has been

studied in the microwave region (wavelengths

<2.6 mm) and in the far infrared (100-600 n).

Observed transitions, rotational constants, electric

dipole moment, g

factor, quadrupole moment Q,

and quadrupole coupling constant (eqQ) and other

properties derived from the microwave spectra are summarized in tables 57-9. Calculated positions

of the pure rotational lines of C

12016 have been

reported by Rao et al., [204].

7.1.

Rotational Transitions in CO

The first microwave study of CO was that of

Gilliam et al., [83] who measured the J=1^0

rotational transition of C

12016 and C13016

. Shortly

thereafter, Bedard et al., [15] measured the J= 1<—

0

and J=2«—1 transitions and obtained a value for

D0 from their frequency separations. Cowan and

Gordy [48] measured the J=3^-2 line in the

0.867 mm region. The first three rotational lines were seen together, and their separations caused

by centrifugal stretching were measured directly

giving a value of D0 close to that of Bedard et al.,

[15]. Gordy and Cowan [86] later measured the

three lowest rotational transitions. Recently,

Jones and Gordy [122] have measured the 4<— 3,

5<— 4, and 6^5 transitions in the submillimeter

wave region. The observed rotational lines are

listed in table 58.

Rosenblum et al., [215] have made the best

measurements of the 1<— 0 lines for a number of

isotopes of carbon monoxide. The measurement

of the magnetic moment [215] made possible three

corrections to B e for the moment of inertia of the

electrons: (a) for the nonspherical electron distribution, (b) wobble of the nuclei caused by rapid

precession of electronic angular momentum in the

molecule, and (c) the Dunham correction between

Y0i and B e . (The magnetic moments and rotational constants are included in table 58.)

Palik and Rao [184] have observed the pure

rotational absorption lines of CO for J=3 to 23

in the 100 to 600 m region using a far infrared

spectrometer with echelette gratings of 90 lines/in.

and 45 lines/in. Positions of the lines from J=0

to 30, calculated from the most precise infrared

data [197, 85] have recently been proposed by

Rao [203a, 204] as secondary standards in the far

infrared.

7.2.

Stark Effect

Burrus [36] has determined the electric dipole

moment of CO to be 0.112 ± 0.005 Debye from the

observed Stark shift of the J=l<— 0 transition.

Mizushima [163] has calculated a small correction

for the polarizability Stark effect making the

final value 0.114 Debye. (See table 57.) Rosenblum et al., [215] claimed to have determined the

sign of the dipole moment from the relative

magnetic moments as corresponding to the charge

distribution C~0+. This is opposite in sign to

that predicted from electronegativity differences

alone. The molecular orbital calculations of

Huo [109] and Nesbet [173] have shown that the

assigned polarity C

_ 0+ is to be questioned. (See

sec. 2.)

7.3.

Zeeman Effect

Cox and Gordy [49] have observed the Zeeman

effect in several linear and symmetric top mole32
cules. For CO the rotational g factor was found

to be 0.268 ±0.005 nuclear magnetons In a

linear molecule without nuclear coupling, the

rotational magnetic moment is directed along

the rotational momentum vector J but may point

parallel or antiparallel as g3 is + or — . Here only

the magnitude of gs was determined, but it is normally considered negative (except for hydrides). For a magnetic field of 10* G the a component separation is 4.08 MHz.

Rosenblum et al., [215] have determined the

molecular magnetic moments for various isotopic

species of carbon monoxide. For C

12016 g3 is 0.2691 ±0.0005 mx- (See table 58.) Burrus [37]

determined somewhat lower values from observation of the Zeeman splitting of the first ro- tational transitions. In a field of 10080 G, the

separation was 4.115 ±0.025 MHz for the <r components of J=l<— 0 and 4.095 ±0.050 MHz for

J=2<— 1. Neither case showed t splitting or

8. Raman, Stark, and Zeeman Effects

8.1. Raman Effect

Rasetti [206, 207] observed the fundamental

vibrational frequency which was excited in 1 atm

of CO by mercury radiation. Observation at 35

atm was made by Bhagavantam [20]. Cabannes

and Rousset [38] observed the fundamental

frequency and, in addition, determined the depolarization ratio p to be 0.29. Amaldi [1] reported the rotational Raman effect at 6 atm

pressure, including the observation of 10 Stokes

and 12 anti-Stokes lines.

8.2. Stark Effect

All experimental attempts to observe the Stark

effect in the electronic spectra of CO and CO+ have yielded negative results because of insufficient

resolution. Svensson [252] observed no splitting

in the B-A bands of CO in fields up to 1 1 5 kV/cm

using a dispersion of 4 A/mm. Steubing [248]

failed to observe splitting in the CO+ B-X bands

with fields up to 67 kV/cm, and dispersion of

5-9 A/mm. Rave [208] observed no shift in

fields up to 250 kV/cm for the A-X bands (CO+

) with dispersion of 10 A/mm. From an assumed

slit width of less than 0.02 mm and estimates of

the resolving power of these authors, Kopelman

broadening which indicates no change in g factor

with J. This appears to be the first check of J

independence of g3 .

7.4. Quadrupole Hyperfine Structure

Rosenblum and Nethercot [214] have observed

the hyperfine structure of the J=l<— 0 transition

of C

12017

. The observed frequencies for the

fully resolved AF= ± 1 transitions are given in

table 59. The value of (eqQ) is ±4.43 ±0.40

MHz. Q equal to —0.0265 ±0.003 barn is obtained from paramagnetic studies on O

17 [123]

confirming a microwave value of 0.026 ±0.009

[249].

The rotational constants B0 , D0 , obtained from

microwave measurements are given in table 58.

The electric dipole moment and hyperfine

structure obtained from microwave measurements

are given in tables 57 and 59, respectively.

in Electronic Spectra of CO and CO+

and Klemperer [134] have estimated the dipole

moments of several states (table 57). To observe

the Stark splitting resolution of better than 0.5

cm-1is necessary.

8.3.

Zeeman Effect

The Zeeman effect, while important of itself,

reveals in addition the existence of perturbations

of rotational levels and the coupling case of

electronic states. Zeeman patterns have been

observed for three systems: B1 S

+ —

A

1 !! (CO),

6

3 2+-a3 n (CO), and A2 ni -X2 2+ (CO+). A

general review in 1934 by Crawford [51] on the

Zeeman effect in diatomic spectra summarizes

most of the work that has been done on CO.

Theory predicts the largest width patterns for

low J, with a maximum for J= A. For large J

values Zeeman displacements are generally immeasurably small, except in the nieghborhood of perturbations where the lines are very sensitive to the

magnetic field. Such Zeeman patterns are large

and irregular.

Kemble, Mulliken, and Crawford [128] and

Crawford [50] have observed symmetric patterns

with displacements proportional to field strength

(up to 35,000 G) for several bands of the B-A

system. Thirteen patterns were observed out of a

33
possible 18 for the first two lines of the P, Q, and R

branches. (Greater intensity was observed for

the low-frequency components of the Q doublets

(]| polarization, AM=0) and of high-frequency

components of P doublets (J_ polarization, AM=

±1) for high J.) Large displacements due to

perturbations of the A1 !! state were observed for

J=23 to 35.

Watson [268, 269] has observed large and ir- regular Zeeman patterns for a number of magnetically sensitive lines in the 0-0 and 1-0 B-A

bands using fields up to 30,000 G. Very violent

perturbations were observed, expecially in the 0-0

band. Numerous extra lines appeared. (See

also ref. 216.) The B1 ^

state, having no magnetic

moment, is insensitive to the field. Watson studied in detail the large displacements

of lines for J )>23 previously observed by Crawford [50]. In the 0-0 band, for Q(12), the displaced lines are strongly perturbed though fields

of 104 G only increase their displacement (but do

not produce a Zeeman pattern). A similar perturbation is observed in the 0-1 band. The state

perturbing A1 !! is either case (a) a

3 II [216] or

d

3 Aj (then thought to be 3 IL) in intermediate

coupling between (a) and (b).

Schmid [236] has observed the Zeeman effect in

the 6

3 2

+ —a

3 n bands in fields up to 29,000 G.

Greater splitting or broadening was found near

the heads than at higher J. R2 branch lines (with

lower state 3 ITi) are seen as sharp triplets with

twice the normal component separation. Rj and

R3 branch lines are weakened and broad. These

effects confirmed the assignment of the a

3 n state

to case (b) by N=23. Also, the 6

3 2

+ state

already displays a Paschen-Back effect for 15,000

G.

Schmid and Gero [223] observed all lines split

into symmetric doublets in the A2 IL—

X

2 2

+ bands

of CO+ (fields 14,000 to 28,000 G). For n1/2 — 2, all doublets reached the maximum value 2Ao-norma i for small J. The separation was smaller for large

J in this subband and for all J in the Il3/2 — 2 subband. Splitting was proportional to the field, and

independent of vibrational quantum number. It

is noteworthy that no deviation was detected to

indicate perturbation of the A2 IIi /2 ) v=5 level

(sec. 4.7).

9. Molecular Energy Levels and Potential Energy Curves

The potential energy curve for an electronic

state of a diatomic molecule represents the sum of

the coulomb repulsion of the nuclei and the

electronic energy as a function of internuclear

distance. This function (or curve) is defined

when the electronic motion and nuclear motion

do not interact directly, that is, away from the

region of a perturbation or predissociation. Reliable potential energy curves can be calculated

from the spectroscopically determined vibrational

and rotational energy levels by the method of

Rydberg-Klein-Rees (RKR).9

9 The foundations of this method can be traced through reference 258.

RKR curves for several states of CO have been

calculated by Tobias et al. [258]. Krupenie and

Weissman [138] have recalculated these using

a numerical method [271] which avoids discontinuities in some integrals. Due account was taken

of revised quantum numbering in some states,

intermediate coupling, and better data in several

instances. There is close agreement with previ- ous calculations [258]. Potential curves for the

three observed states of CO+ are included for the

first time.

Table 74 lists the term values, vibrational

quanta, and turning points. The potential curves

are displayed in figure 1. An energy level

diagram is given in figure 2.

34
10. Transition Probabilities and Lifetimes (Electronic Spectra)

The integrated band intensity in emission is proportional to the relative vibrational transition

probability or band strength which can be approximated by £v*,"=R*(r)g, where Rc is the

electronic transition moment, and q

is the vibrational overlap integral square. The conditions

under which this equation is valid have been

discussed by Fraser [67]. It is often assumed

that the electronic transition moment Re is a slowly varying function of r and that Re can be

replaced by an average Re (7y„"), where the r- centroid is given by

- = f^v’r\jyV "dT

J'4/v'^v"dr

When Re fluctuates considerably (perhaps even by a factor of 5) then the Franck-Condon factor

q becomes a poor approximation to the band

strength, and the validity of the Born-Oppenheimer approximation breaks down.

The origin, properties, and methods of computation of r-centroids are discussed fully by

Nicholls and Jarmain [180]. Detailed discussions

of the concepts involved and the work done on numerous molecules can be found in a series of

reviews [133, 242, 174, 175, 181, 178].

Evaluation of the Franck-Condon factor, the

dominant term in the band strength, depends on

the potential energy curves of the states involved.

In virtually all cases (for CO and CO+

) Morse

functions have been assumed. Tables 60 to 72

summarize the numerical data on Franck-Condon

factors, band strengths, r-centroids, and I^

) for a number of electronic transitions

X v'v"/

in CO and CO+. Lifetimes and oscillator strengths

/ for several transitions have been measured

(table 73). The experimental work and calculations are discussed below (including for some

transitions, determination of the functional

form of Re) . The few quantitative measurements

of band intensities are mentioned.

10.1. A1 !!— X’S+ Fourth Positive System

Franck-Condon factors q have been calculated

by Nicholls [178] (table 60a), and r-centroids have

been calculated by Jarmain et ah, [113] (table 60b).

Other less extensive calculations of q are in substantial agreement with the above values, except

for some rough estimates [195] for high quantum

numbers which differ by more than a factor of 10.

Nicholls [176] has shown from visual band intensity

observations that Re should be only weakly

dependent on r for a number of bands with

r' — 0 to 4, so that, for these, p is well represented

by q. Silverman and Lassettre [238] have reported

good agreement between the experimental relative

intensity for the r" = 0 progression observed by

electron impact with those obtained from FranckCondon factors [113] corrected for band overlap.

Lassettre [141] has indicated that more recent

measurements with lower energy electron bombardment (and greater resolution) give poorer

agreement.

10.2. B

1 ^—

A

1 !! Angstrom System

Ortenberg [183] and others [150, 14, 211] have

calculated Franck-Condon factors (table 61) in

substantial agreement with one another, by

assuming Morse functions with we xe estimated

(23 —27 cm-1

). These values (some with v' up

to 11) are all rather uncertain because no level of

the B state has been identified with certainty for

F>1 because of predissociation. Robinson and

Nicholls [211] have calculated r-centroids, p, and

loo (table 61). Robinson [210] and Robinson and

Nicholls [211] have measured relative intensities

for the 0-0 (8.2), 0-1(10), 0-2(3.2), 0-3(5.3) bands

of the r' =0 progression. Re (r) is given const.

(0.768

r

2 — 1.745r— 1) for 1.12 A^r^l.lO A and

is almost independent of r in this range.

10.3 C1 2+ —ATI Herzberg System

Leskov [150] has estimated qfor several bands

(table 62) assuming a Morse function with uex'e estimated as 18.07 cm-1

. These values are uncertain since only the r=0, 1 levels are known

for C'SL

10.4 fr

:! 2+ —

a

3 n Third Positive System

The absence of any recorded bands of the b-a

system for v'^>2 prompted Barrow et ah, [13] to

look into their intensity distribution. From

assumed Morse functions, and the use of the

794-908—66- 4 35
Pekeris relation (ref. [99], p. 108) an estimate was

made of q relative to g(0-0) and compared with

their measured relative integrated band intensities.

Comparison of intensities with q showed that Re varies significantly with r. Using a crude vibralional temperature and the ratio

^. ^) an

. . 2(0-0)

estimate was made of the relative intensity of the

2-0 band to be 0.023 times that of the 0-0. A

very long exposure at the expected wavelength

of the 2-0 band showed no sign of a violet-degraded

band, though some overlap by A-X bands

prevented a categorical denial of the existence of

the v'—2 level.

The 2-0 band is thus much weaker here than

expected. If this be due to predissociation, then

D° (CO) <Cl0.94 eV. If the perturbations of

b, y' =0, 1 extend to v'=2 it is not clear how this

could suppress the band completely [13]. It is suggested [13] that further study of b levels be

made from the b-a and 6-X systems in C

12016 and

C

13016 to clarify this contradiction with the

accepted dissociation energy.

Values of q, r-centroids, p, and I ro have been

calculated [210, 211, 179, 256, 183] (table 63). Re (r) is given [256] as const. (0.943r-l) for 1.08A<

r<1.16 A, which confirms the large fluctuation

observed by Barrow et al., [13]. In view of the

crude approximations (estimates of weze) involved

in determining the potential functions, it is suggested that the tabulated parameters be accepted

with considerable reservation, since the b state is predissociated. Schwenker [237a] has measured

the lifetime of the b-a transition and calculated

the oscillator strength (table 73a).

10.5.

a

/3S+ —

a

3 n Asundi System

Jarmain et al. [114], have calculated FranckCondon factors assuming modified Morse functions

(table 64)

.

10.8 a

/3 s+—

X

J S+ Hopfield-Birge System

Nicholls [178] has calculated Franck-Condon

factors for a large array of these transitions ( table

67).

10.9. cPAi— a

3 n Triplet System

Pillow and Rowlatt [188] have calculated I®

(=7V»"A4

) from the data of Herzberg [99] by

using Pillow’s distortion method and implicitly

assuming that R6 is constant. Approximate mean

wavelengths are quoted for the Triplet bands.

Singh and Jain [239] have calculated q and I„, from the same data as Pillow and Rowlatt, but

assuming Morse functions. The two sets of values

of U diverge from one another for F)>5, with

the Morse-based values preferred. Herman and

Rakotoarijimy [93] have made measurements of

the relative intensity of emission bands of the

v" = 0 progression observed in a high voltage

discharge in CO diluted in xenon, and have calculated the N„ distribution. It is shown that, in

this discharge, resonance excitation due to collision with metastable xenon atoms selectively

populates the v' — Q level. [In the above, cor- rected vibrational assignments have been used.]

Singh and Jain [240] have calculated q and r- centroids after having determined that the Morse

function closely approximated the Rydberg-KleinRees (RKR) potential over a small range of v. (Their q’s are essentially those of ref. 239.)

Assuming Re is approximately constant, they

obtained I ro from the Franck-Condon factors and

estimates of comparable to those of Herman

[93]. All the above references use v' one unit

lower than the revised numbering used here.

This makes the numerical results somewhat uncertain. In any event, the assumption of constant

Re is untested. The values of q, r-centroids and

I a, are given in table 68.

10.10. A2 n,-X2S+ (CO+)Comet Tail System

10.6.

fl

3 n-X1 S+ Cameron System

Jarmain et al., [114] have calculated q’s assuming

modified Morse functions (table 65)

.

10.7.

6

3S+ —

X

1 ^

Hopfield-Birge System

Nicholls [178] has calculated q’s for the first

two v' progressions (table 66).

Bennett and Dalby [19] have experimentally

determined the oscillator strength \f) for this

transition, which was derived from the observed

spontaneous emission lifetimes of several vibrational levels of the upper state. These quantities

are given in table 73. The lifetimes decrease

slightly with increasing v'

,

but are independent of

CO pressure over the range 0.2 n to 6 n- Constant

Re is assumed here.

36
Arrays of q, r-centroids, p, and I m have been

calculated [212, 177, 243, 114, 41] (table G9).

Robinson and Nicholls [212] have measured

relative band intensities photoelectrically. Absolute variation of Re (r) is obtained [212, 177]

as 43(— 1 + 1. 73r— 0.74r2) over the range 1.10

A <><+.21 A (a fluctuation of 20%). The

Einstein A coefficients, absolute band strengths,

and band oscillator strengths were estimated

(table 73) [177] for the A-X bands by combining

the lifetime (r c ) measurements of Bennett and

Dalby [19] with the relative band intensities of

Robinson and Nicholls [212] for a number of

bands.

Spindler and Wentink [243] have obtained

R e = 1.077 + 0.021 Debye independent of r between

1.074<r< 1.184 A by using the lifetime measure- ments of Bennett and Dalby [19]. The disagreement between these two determinations of Re is attributed [243] to possible systematic error in

the intensity measurement by Robinson and

Nicholls [212] due to regions of strong overlap.

This discrepancy together with the nonconstant

lifetimes r' from the 2-0 and 2-1, and also the

1-1 and 1-0 bands [19] makes desirable a recheck

of the A-X Comet Tail system. (The calculated

Einstein functions of ref. 243 differ by a factor of

2 from those of ref. 177.) The calculated absorption f numbers disagree by a factor of three.

10.11.

B2S

+ —

X

2S+(CO+

) First Negative System

Nicholls [177] has calculated a large array of

Franck-Condon factors and r-centroids (table 70).

Lawrence [143] has measured lifetimes by means

of the phase shift method and obtained Einstein

coefficients and oscillator strengths for this system

(table 73). Schwenker [237a], using a more conventional technique, has also measured the lifetime of the B state which is about a factor of 2.5

smaller than that of Lawrence (table 73a). The

discrepancy between these two values has not

been explained.

10.12.

B2S+-A2 IL(CO+) Baldet- Johnson

System

Nicholls [177] has calculated Franck-Condon

factors and r-centroids 10.13. (table 71).

Ionization of CO

Wacks [264] has calculated Franck-Condon

factors for ionizing transitions from X'2+ (CO),

v=0 to the X2 2

+

, A2 !!,, and B2 2

+ states of CO+ using Morse functions (table 72). In his consideration of ionization efficiency curves, it has

been assumed that R e (r) does not fluctuate.

Halmann and Laulicht [88a] have since made a more extensive calculation for three isotopes of

CO (in all cases assuming Morse functions).

10.14.

Miscellaneous

Integrated oscillator strengths for the A-X,

B-X, and C-X transitions in CO have been

obtained by Lassettre and Silverman [142] from

inelastic electron scattering (table 73a). Absolute

/-values for bands of the A-X and B-X systems

have been determined by Hesser and Dressier

[102a, b] from measured radiative lifetimes and

previously calculated Franck-Condon factors [178]

(tables 73a, c). The sums confirm the

V

f magnitude of the integrated /-values [142].

Fox and Hickham [65] have measured the

I ( \) relative ionization probability to be

y~y = 0.2.

For the CO continuum between 880 A-374 A,

the /-value is 2.8 [251].

11. Summary and Conclusion

The aims of molecular spectroscopy include the

determination of energy levels, molecular constants, potential energy curves, elucidation of the

electronic structure, and the determination of

transition probabilities. The status of our knowledge of these properties of CO, CO+

, and C02+

will now be summarized.

Precise measurements were made years ago on bands of the B-A system, and more recently on

the a'<— X, X, d—>a, E^-X systems and the

three transitions of the ion. However, for several

of these, only a few vibrational levels have been

carefully studied. Work is in progress on analysis

of high dispersion measurements on the A-X,

37
e-X, d-X, I-X, and a'-X transitions [100, 238a].

Definitive measurements have been made of the

lowest pure rotational levels (X1 ^, v=0) and for

the lowest vibrational quanta (IR) in the electronic ground state. From these data, precise

molecular constants have been determined which,

together with the well-established dissociation

energy, characterizes the Xx 2

+ state as the best

known for CO. However, even for this state, the

vibrational levels (and potential energy curve)

are known only halfway to the dissociation limit.

Much is known about the states lying below

the first dissociation limit (11 eV), the singular

exceptions being the /

3 2

+ and F2“ states. For

most states lying above 11 eV, including all Rydberg states, the symmetry type, multiplicity,

electronic structure, and dissociation products are unknown or uncertain. No Rydberg series have

been observed in emission. Quantitative data

are not available for any repulsive state. Isotopes should be used to make unambiguous

all vibrational quantum assignments. Critical

re-examination of perturbations is needed, es- pecially those pertaining to A1 ]! and 6

3 2

+

, to

unravel the overlapping structure of various

states. Terms of the a' 3 2

+ and f"2

+ states near

the dissociation limit have not been separated.

Franck-Condon factors based on Morse functions

have been calculated for many transitions, but

these values should be considered tentative.

Quantitative intensity measurements are virtually

nonexistent.

Two states of C02+ have been observed only in

electron impact experiment.

Note added in proof. Bands of the T<—X and

S^-X Tanaka progressions have been reclassified as belonging to new B-X Rydberg series III and IV,

respectively (Ogawa, M., Rydberg series converging to the B2 2

+ state of CO+

, J. Chem. Phys. 43,

2142-4L (1965).

I am grateful to A. M. Bass for suggesting the

review of the spectroscopic data on CO and for

discussions with him which were useful in determining the scope and format of this review.

Thanks are due also to C. Edmiston, T. Carrington, and M. Wacks for their helpful discussions.

I wish further to acknowledge the effort of Mary

Kirstein in carefully preparing the manuscript.

38
794-908—66

(face

p.

38)

n

ID

t,

h

e

stvt

il

ci

5r

y

bi

s

0('n)

F('I*)

158003

133130

] 1 30211

154302 II

1 44730 II

128800 II

12878K II

120410 II

106200 II

00730 II

08830

02030 03

02070. 1

01010. 1

00800. 2

(80880) II

80017. 7

83832. A

(83741)

(<00230)

(06033)

04740. 6

03708. 02

00040. 03

168884

133740

13007

(164700)

( 144007)

( 120107)

120043

120712

(106700)

(00806)

(02046)

(80028)

(83708)

MO configuration

(3»)(4a) (I r) (6#)(2fl) (0#)Ry

04230. 32

01164. 00

•P,* +

’IV + MY+

•P + ’P

•P + 'P

»P I »P

•P+’P

•P+’P

Table 1. Molecular eonManU

Dissociation energy

D* I)*

k, WrX. «.y. «4. r *

37538

40002

38398

47680

10* dyntl

cm

12. 147

9. 850

1734. 18

1562. 06

27. 027

U 532

0. 3283

A

1. 16878

68412 19. 804

7. 405

2214. 24

( 1354) II

15. 164

(9)

-0. 0007 1 11516

10 877 (1641) H (4. 8)

9. 931 1568 H 11. 0

9. 805 1558 11 10. 6

9. 918 1567 H 13 6

4. 861 (1097)

18 017 2112 H 198

18. 395 (2134) H

(1. 409)

[

1 I'M 1

]

19. 196 (2146. 4)

<1000 1. 442

(2082. 07)

(2188)

1. 120

19. 338 1. 113

(5851)

(23902) (24492) (4. 57) (1063. 8) (1. 416)

24848 25601

26886 27440 5. 005

28948 29522

34241

41121

34854 6 118 1230. 051 11. 0130 0. 07378 -0.00115 1. 3519

89460 90542 19. 0176 2169. 8233 13. 2939 0. 0115 1. 57X10-* 1. 128322

1. 70002

1. 58040

1 07720

(I. 130

(

I 0044)

[ I 0603)

1. 001

1. 080

(0. 85)

<1.6

(1.220)

1. 6116

1. 2848

0.027

0. 042

0. 0181

0. 01677

0. 01872

0.0195

0. 017613

-0. 000105

0.0001

0. 000205

2.06X10-'

7. 75

0. 60

a 37

a 22X10*'

~0

a oi

860. 15

777. 65

1103 33

(675)

(819 3)

781. 1

776 3

780. 1

(549)

( 1006 A)

(1067)

-0. 9870X10 *

Zero pt.

energy

(1072)

(1116)

554. 10

674 46

612. 577

808 16

1081 690

Observed Spectral llund's

train it nm System name region coupling (0B8

References Remarks

case

X

B—V Bsldot-Johnson 4240 3310 2U5. 160. 11 8. 10 s»(0 0) - 25226 06. s, - 25 143 65

B-X u First Nrgatu. 3160 1800 6 10 202a, 206 #l(0

0) - 45633 52. #. 46H76 70 A-X V Comet Tail 7200 3080 II 202b, 205 *,(t> 0) — 20407 47. e. 20 733 15

6 T—

S-X It Tanaka 690 670 3 254

It- X

Q-X

1*-X

Q-X 060

F— X R llopfirid-tllrgr 1000 0 104,117 #»(0 0)- 99730

‘II—It 1130 1010 0 •„(0 0) UKH39, e.(0 III - UH830

K-X V Hopfli Id Blrgi 1080 1060 b 1 104, 257 •n (0 0) - U2023, ««(0 0) - 92010 1)3

c —a V :iv 2710 2300 0 77,99 s,(0 0) - 43602 1

ex V 1 K' 1110 IO0O 6 i 209, 224. 370 e,(ll 0)-9IU 19 1

K ~*a V Kaplsn 2750 2520 0 125 e„(0 (I) - 41415 (calf .)

B-.A V Angstrom 6620-4120 224 #e(0 0) -33171 2 B-X V BopBi 1

1- Hugs-. • 1160 HIM) (2 209, 255 e„(0 0)- 869 17, 3

6 —*a V 3830 2600 240. 76, 99 A

6—V llo|iflvld. lilrgc 1190 1 130 b 1 104, 99 Ml

A-X R Fourth Positive 28181 1140 20 209. 228 •*(0 0)- 04740 6

s.(0 (0 — 037OH 92

d—a It i Hpfa 1 7500 3770 40. 82 -.m ni I317B

d— X R 1020 1230 O-b 22 256

o’-X R Bopfll Id Oirg. 1810 1280 b 23 101 T .in 0) UIU 91

o~X R Guuroo 2580 1770 O-b 7 201, 277, 321. .,(0 0) - 4847 3 9 7

17,209, 197, 1UH

ii^.u*-8j)Mxi»-"nr)

r. has broil reticulated auumlng atomic point masses Correction! tor nantpherlcal electron distribution and wobble stretching reduoo thl»

1«T. SIB). Uncertainly In the value of A probably makes any determination of r, uncertain In Ihe tilth figure

reported at SMSOcm-i to be ipurlou*. Prarar and Osydon |I8<1 Include It In thrlr tabulation!. (See tec. (K): Hcrilierg |UU| considers It

- |»b)

I MIOJ ci

) <1U(|)-17M.IU an-' bom tend origins l'»lj

1 T,-e.(O-0) la reticulated |IUI |

i) l,«-t.lX19‘*cm-i |I(U)

) A+(y--l IS |I01|

) Schmitt and tlerO |.‘3ta) list term value! oblali II throe perturbation! are dt

(a) e»(0-<i: calculated from band origin! with r' value! (lot) raised by unity |.'3aa| Rotational coo stents have also barn recalculated In this way

(b) !+»>--fOMcm-Mimi

"• (a) Provisional constant! lor this stale art baaed on pertu/lstllon data |U) and recant observation of the I—X bands (luD]. Analysis of I twee

bands is not yrel available

(b) Howell (100) aaeumril that the I itate dlasoeUUi to *D+'D which gives r>*~« 3 r V (too large).

1 Keallty of a stale at thla energy (<M2» an-*) te unrertaln |l«o|.

>: Vltestlooal alignments tor the two bands attributed lo this stele are unknown The Urtn value of thla atate te uncertain Harem* on.

likely that the bonds otwrvod In ref 7* originate from the a'* I" elate (Sr* tec. 1 1«.)

lleriterg |WJ lists dU i|i - dv* an-* which it taken from (73| 3etori*(IIJ|llaUZniem Schmid and OerA|Ut| list Jl® on -• Asundl a

data (4| glvre m3 cm-' from bond head measurements The value listed lore (nag| la taken from |24C| who also obtained I to rotational

constants Hated above. (Ileriberg lists B.-ItUSan-'.o.-O'tBcnr* which are token from |Z»| ) AD constants toe the 3 Malt are obtained

from the perturbed structure and are uncertain.

<•> nil* Identification 12231 of « -3 la correct then the B stats would land todtenclatc to HI -fit) with an appsrenl D*ol~4#V. It la. Itowevar,

terdlsaociale.l by a •P+J l

> stale

(b) Jevons (1171 lists w.^ZIk.’, but gives no reference Only the d()(|) given above la prrclatly known Using Ite date of [D4. 1W|

gives ipfcoilmole values w.-.'l #4. ~,r.-ll from which the 7.PK was eel luxated.

dO(|) has been determined born band origins. w^~21SO) and «.r,(~lA.B) ore estlmatrs from which the It PR has baao obtained, a, and

11. are tentative values (7T*J,

I: (a) llenbrrg |»>) Hats which lathe biw as )evona|ll7|. but norelrrenre Is given k» «-|. Tilted at ai|337| have observed a band

head about thl* dir* anon from their K-X, (>« band.

(b) B« lor this Kate Is obtained only from the R* levels (A doubling It very small) ftS7),

I (a) Though only «*» tend »«

(b) ThreitraordinarUy large

elks r * lt«*|and )*.«*<! |III|IU

Reproduction* of a|tcclra

| 202s)

1 202b

|

[66, 269)

(64,226,76)

1101)

lift"!

1274)

Moil

(79,201)

(102, IUI, I U3 1 VIII ROT.

*t rapSdly , Its l»* by linear Blrm *t««*r e ilrafAatlaa

Wat* I* te IrlpM lUaw-talM) lo HI , >|l, If II war*

a ilaglrt Kate, teems unMkely te Uil* re quire* !•*—J I* V (te. htghi tebhvre l».W«i .1 al (Ilf) have ttewetle.ll, naleuleta.l a Hydterg

elate at Ihlteseny lo te (pisKUy) >f If f It Ulptol , I tew Iter. nnK te Wrawg sitrlsg wMb a Knglrl Kata tesiptaln Ite greal munstl,

elite r X InnaMtei

Ot>ni: Only eao band la repcrlad tor Ite (I X system Her. ter* |e*l U*U ..XIOT), tel gleet aoreteenm.

I anal a hand! n> to, tranatl tow frew. Ite gfread Wat#

XIMCO'I !•*“• gale V.

AUdCO*) (a) >|*>erl«eouplta|«MraM A--IITJWto -• |«0t.. W|

(b, D*-»11S.V

BIMCO*) ir-MMaV

CO* (a) Uncertainly lam cm >-0 004 a V) Is Ite hr* to

T , and T. toe Ite sales af CO*. The retail** te

(try A Sale haeienteiiT.lt teen IdteilSrd ai TfV HaV Is

38a
• • •• - 'yv •••-

'

'' :

: ;

• SeMirai •

•

'

ft no -

•

• -

id »j9l. •. bh xidwtew *to otter & PaMwaU .p« A*1 ="*«• •iKJOOO;'‘ •" '

. . se ?*." .11 : 0. -n-.-.OCit U K- . -J •'• •• ' ?

IPV6 j,> 1 *3,10 »s» u ban • i ao bsead (i>0- to * - -nc : ; >- »i - • (h: ' T

'

.i-mo SO#- i i.. «H vr.iit -insOi'-

[ 4) vtfah« bn. : ‘ :•••*>

j 10 II fc •>•(.. v yj -H 1 , [io i i -mo *-pr; S'

oji» ion si Jl .U=«oi Jcb rt^«tetr4»a m<ni bnaiaMo a^Uv mr.J lo »t*0 bn.- t-ia »

. 933 . 9.U .'noil aiJiiii j r

- i: - " '

e.c -i c a .« l£8 .OH ‘-flio «.n-=,Y {'-m )
Table 1. Supplement. Rydberg states Table 2. Electron configurations for stales of CO and CO+c

Series State {n) To CO e w,-Xt Reproduction

of spectra

B(CO+)*—

X

° 4 137760 /8 series [254] 5 148712 (1739) (22. 8) 6 152812 (1737) (20. 3) 7 154820 Sharp 8 155943

9 156637

10 157082

11 157416

12 157627 Ref. [2£ 4]; (a) Ref [107]

a 4 139530

5 149105

Diffuse 6 153004

7 154943

8 156053

9 156728

Ref. [254]; (a) Ref [107]

A(CO+)<-X 5 123335

6 127436

7 129431

8 130659

9 131323

: Ref. [254]

X(C0+)«-X 6 106576 [2185]

7 108849 [2171] 8 110084 [2181] 9 110865 [2161] 10 111357 [2181]

11 111707 [2175] 12 111957 [2172] 13 112145 [2167] 14 112284 [2167] Ref. [253]

a These Rydberg states all converge to the ground state of CO+ [147].

b The d state is d3 A,- [40, 137],

rrspi+orspi I X12+’ 12+1 a

' 32+’ /32+’ ‘ 2+(2) > II2" e32" S2_>

1 1 ; lA'R, IRC, am, 3n, 50(2), 1A«, d3 A<, «A

c in or 3 A possibly lies below 66230 cm-r

All above Rydberg series observed in absorption.

39
Table 3. Band heads of the A1 !! — X^4- Fourth Positive system ( R)

ta) Emission

X a I v'-v" Ref. X I v'—v" Ref. X a I v'-v" Ref.

A cm-1 A cm-1 A cm-1

2799. 7 35708. 2 9 9-22 2137. 0 46779. 9 5 7-14 1603. 3 (62371. 4) 1 9-7 L

2785. 4 35890. 3 8 4-18 2128.3 46971.

1

8 3-11 1597.14 62611.8 8 0-1

2742. 6 36450. 7 6 11-23 2113. 07 47309. 51 9 6 13 182 1595. 60 62672. 4 2 6-5

2740. 0 36486. 0 4 7-20 2107.2 47440. 3 7 2-10 1576. 67 63425. 0 8 2-2

2712.

1

36860. 5 4 6-19 2089.9 47834. 0 10 5-12 1560. 14 64096.9 7

a l-l

2698. 30 37049. 38 6 13-24 74 2086.9 47901. 5 1 1-9 1559. 47 64124. 4 8 4-3

2684. 0 37247. 4 3 5-18 2067. 71 48347. 17 10 4-11 73 1545.3 64712.

8

4 b 6-4 90

2680.8 37291.

5

5 9-21 2046.3 48852. 9 10 3-10 1544.2 64758. c 0-0 255

2662.

9

37541.

8

4 12-23 2034. 35 49140. 0 4 6-12 90 1542. 34 64836.4 8 3-2 2661.5 37561. 7 4 15-25 2031. 7 (49204. ) 1 9-14 L 1534.2 (65180. ) 2 8-5 L

2659. 6 37587. 9 4 4-17 2025.

8

49347.

8

9 2-9 1527. 52 65465. 5 3 5-3

2630. 0 38011.4 6 11-22 2011.

8

49690. 6 8 5-11 1525. 75 65541. 6 6 2-1

2598. 31 38475. 05 4 10-21 73 2005.

8

49839.

8

5 1-8 1520.4 (65772. ) 1 12-7 L

2594. 5 38531. 5 1 16-25 1990. 89 50228.

8

2 4-10 1515. 7 65977. 9 3 7-4 90

2567.

8

38932.

8

5 9-20 1970. OS 50759. 3 3 3-9 1510. 4 66206. 3 2 4-2 90

2556. 03 39111. 51 3 12-22 74 1950. 07 51280. 2 3 2-8 1509. 66 66240. 0 6 1-0

2538. 6 39379. 7 4 8-19 1939.12 51569. 9 1 5-10 1506.8 (66366. ) 2 9-5 L

2524.

1

(39606. ) 4 11-21 DE 1930. 70 51794.8 3 1-7 1497.

8

(66764. ) 3 6-3 L

2521.

8

39642. 7 3 14-23 1918. 08 52135. 4 2 4-9 1493. 60 66952. 3 6 3-1

2509. 9 39830.

1

8 7-18 1912.8 52279. 9 1 0-6 90 1488.0 (67204. ) 2 8-4 L

2492. 86 40102. 42 8 10-20 73 1897. 83 52691. 6 4 3-8 1480. 2 67556. 6 2 5-2 90

2483.8 40248.

8

3 6-17 1891. 2 (52876. 5 ) 6 6-10 L 1477. 48 67682.

9

3 2-0

2463. 22 40585. 12 10 9-19 73 1878. 33 53238.

9

7 2-7 1475.4 (67778. ) 1 12-6 L

2458.0 40671. 5 2 5-16 1870. 3 (53467. 4 ) 3 5-9 L 1473. 0 (67889. ) 1 14-7 L

2433. 9 41057. 5 9 8-18 1859. 41 53780. 4 5 1-6 1463.4 68333.3 10 4-1 90

2424. 20 41238.16 5 11-20 74 1850.1 54050.

8

1 4-8 90 1452. 17 68862. 5 5 6-2

2407. 6 41552. 0 7 7-17 1846.7 (54150. 6 ) 2 7-10 L 1447. 27 69095. 4 1 3-0

2394. 2 41754.2 3 10-19 1841. 47 54304. 6 1 0-5 1443.7 (69266. ) 1 8-3 L

2393.

1

41773. 9 4 13-21 1829. 81 54650. 6 4 3-7 1435.28 69672. 9 7 5-1

2381.

6

41975.3 6 6-16 1825. 38 54783.

1

1 6-9 1425. 78 70137.2 5 7-2

2365. 47 42261. 95 5 9-18 74 1810. 82 55223.

8

8 2-6 1418. 91 70475. 6 1 4-0

2356. 5 42422. 3 4 5-15 1804. 71 55409.

8

2 5-8 1414.0 (70721. ) 1 11-4 L

2337. 95 42759. 48 7 8-17 73 1792. 38 55791.

7

8 1-5 1411.4 (70852. ) 1 13-5 L

2332. 5 42860. 0 3 4-14 1784. 9 56026.

8

1 4-7 90 1408.86 70979. 6 5 6-1

2311. 47 43249. 27 8 7-16 73 1774. 90 56341. 3 3 0-4 1401. 02 71376. 5 3 8-2

2309.7 (43282. ) 4 3-13 DE 1747. 20 57234. 4 4 2-5 1395. 7 (71649. ) 2 10-3 L

2301. 7 (43433. ) 2 10-18 DE 1743. 12 57368.

4

1 5-7 1391. 07 71813.8 1 5-0

2286.1 43728. 5 7 6-15 1729. 25 57828.

7

7 1-4 1384. 00 72254. 2 3 7-1

2273. 9 43963. 4 3 9-17 1723. 79 58011. 9 2 4-6 1377. 75 72582. 3 2 9-2

2272. 3 43994. 0 1 12-19 1712.19 58404.

7

4 0-3 1373.7 72796.

1

i 11-3 90

2261. 7 44200. 0 9 5-14 1705. 16 58645. 7 3 3-5 1371.8 (72897. ) 2 13-4 L

2247. 2 44486. 6 7 8-16 1704. 30 58675. 2 2 6-7 1368. 0 (73099. ) 1 6-0 L

2238. 3 44663.

8

9 4-13 1684.9 59350. 0 1 5-6 90 1361. 3 (73459. ) 2 8-1 L

2221. 5 45001.4 10 7-15 1669. 68 59891.

8

4 1-3 1355.84 73755. 0 i 10-2 2215.8 45115.9 3 3-12 1653. 02 60495. 5 1 0-2 1353. 6 (73877. ) i 12-3 L

2196.

8

45506. 4 10 6-14 1647. 90 60683. 4 4 3-4 1339. 0 (74683. ) i 9-1 L

2194. 0 (45565. ) 6 2-11 DE 1630. 40 61334. 6 8 2-3 1335. 0 (74906. ) i 11-2 L

2188.

1

(45687. ) 2 9-16 DE 1629. 61 61364.4 8 5-5 1316. 0 75986. 7 i 12-2 90

2173.01 46004. 67 9 5-13 73 1623.4 (61599.1 ) 1 10-8 L 1299.3 76965. 7 i 11-1 90

2161.6 (46248. ) 8 8-15 DE 1615.1 (61915. 7 ) 2 7-6 L 1280. 5 78091. 4 i 12-1 90

2150. 2 46492. 6 8 4-12 1611.26 62063. 3 3 4-4

Air wavelengths above 2000 A mostly from Estey [60]; vacuum wavelengths below 2000 A mostly from Read [209], Inaccurate head measurements by

Deslandres=DE, and Lyman=L are taken from ref. 23 and indicated here by parentheses ( ). Original measurements of Read [209] and Headrick and Fox [90] were all in vacuum.

» Position calculated by Read [209], head obscured.

b Quantum assignment by Read [209]; band observed by Headrick and

Fox [90],

0 Absorption [255],

40
(b). Absorption

e?' v"=Q a I !)"=1 a I

X X

A cm—' A cm—i

0 1544. 2 64 758 6 1597.

3

62 606 3

1 1509.

8

66 234 7 1560.

1

64 098 2

2 1477.

5

67 682 7 1526. 8 65 496 3

3 1447. 4 69 089 8 1493.

9

66 393 4

4 1419.

1

70 467 10 1463.

5

68 329 7 5 1392.

6

71 808 8 1435.

3

69 672 10

6 1367. 7 73 115 7 1409.

1

70 967 9

7 1344.1 74 399 5 1384.

2

72 244 9

8 1322.

1

75 637 3 1360. 8 73 486 6 9 1301.

4

76 840 2 1338. 8 74 694 5

10 1282.

0

78 003 1 1317. 8 75 884 3

11 1263.

6

79 139 1 1298. 6 77 006 2

12 1246. 2 80 244 0.7 1280.

1

78 125 1 13 1229.

8

81 314 0.4 1263.4 79 151 1 14 1214.

3

82 352 0.3

15 1199. 8 83 347 0.1

16 1186.

1

84 310 0. 07

17 1173.2 85 237 0. 05 18 1161. 2 86 118 0. 03

1920 1139. 7 87 742 0.02

Data taken from Tanaka, Jursa, and LeBlanc [255]. (Birge, Nature 124, 182-3 (1929) referred to measurement of the 0-0 to 15-0 transitions In absorption by Hopfleld and Birge; details were never published.)

41
Table 4. Deslandres table for the band origins of the A1 !! — X*2+ Fourth Positive system

This table is essentially that given by Herzberg [99] with the additions he mentioned which have large quantum numbers. This is supplemented by

origins at low quantum numbers based mostly on data of Tanaka, Jursa, and LeBlanc [255].

( ) Signifies data of much lower accuracy than the rest.

42
Table 5. Band heads and origins of the A’H — X‘2+ Fourth Positive system of C13 010

( R

)

(a) Emission

X// <TH *0 v'—v"

A

2613.

8

cm~1 38247.

3

CTO-1

38234.

1

8-20

2564.

5

38982 38972 10-21

2559. 39058. 8 39043. 7 6-18

2535. 3 39431.

4

39420.

0

9-20

2507.

2

39873.

4

39861.

3

8-19

2463.

2

40586 40576 10-20

2454.

2

40733.

4

40719. 7 6-17

2429. 5 41148.0 41133. 4 5-16

2405. 7 41555.

9

41540.

4

4-15 2368.3 42211 42202 10-19 2356.0 42431. 3 42418. 7 6-16

2340. 8 42707 42697 9-18

2331. 9 42870.

2

42856. 8 5-15

2314. 3 43197 43187 8-17

2308. 6 43302. 2 43288.

1

4-14

2264.

1

44153. 4 44141. 8 6-15

2240. 6 44616.

7

44604. 4 5-14

2226. 7 44896. 2 44886. 5 8-16

2217. 9 45073. 2 45060. 2 4-13

2201. 9 45402 45391 7-15

2178.

0

45900.

0

45889.

2

6-14

2155.

0

46388.

2

46376. 8 5-13

2133. 0 46868.

6

46856.

5

4-12

2120. 3 47148.

9

47139. 2 7-14

2111.7 47340.

4

47327. 7 3-11

2097.

0

47672.

3

47662.

1

6-13

2091.

3

47803 47790 2-10

2074. 7 48184.

2

48173. 5 5-12

2053. 2 48689. 5 48678.

3

4-11

2032.

4

49186.

4

49174. 5 3-10

2020. 8 49469 49459 6-12

2012. 5 49674. 5 49662.

1

2-9

1999. 8 50005. 2 49995.

1

5-11

1978. 8 50535. 2 50524. 6 4-10

1958.

6

51056. 7 51045. 6 3-9

Data from McCulloh and Glockler [157b].

(b) Absorption (R)

XiT <TH I v'-v"

A cnr1 1510. 5 66203 6 1-0

1478. 8 67622 6 2-0

1449.3 68999 8 3-0

1421.

4

70353 10 4-0

1395. 71664 9 5-0

1370. 8 72950 8 6-0

1347.

7

74200 5 7-0

1326. 0 75415 4 8-0

1305. 3 76611 3 9-0

1286.

2

77748 2 10-0

1267. 7 78883 1 11-0

1250.

6

79962 1 12-0

1234.

2

81024 0.8 13-0

(1218. 8) 82048 0.6 14-0

1204.

4

83029 0.5

15-

0

16-

0

1177.8 84904 0.1 17-0

Data from Tanaka, Jursa, and LeBlanc [255],

Table 6. Band heads and origins of the B'2+ —A’n

Angstrom system ( V)

X// <TH I v'-v" Ref. <ro Ref.

A cm-1 cm-1 6620. 34 15100. 8 7 0-5 121 15107.

2

121

6298.

5

15872 2 1-6 23

6079. 94 16443.

0

9 0-4 121 16449. 8 121

5817.

0

17186 2 1-5 23

5610. 15 17819. 9 10 0-3 121 17827.

2

121

5397. 5 18622 2 1-4 23

5198. 22 19232.

0

10 0-2 121 19240.

3

121

5015.

0

19935 1 1-3 23

4835. 24 20675. 74 10 0-1 224 20682.

1

224

4697 21284 2 1-2 23

4510. 86 22162. 65 10 0-0 224 22171.

2

224

4392. 93 22757. 48 8 1-1 224 22763.

9

224

4123. 55 24244. 13 7 1-0 224 24253.

7

224

Data from Johnson and Asundi [121], Schmid and Gero [224], and Birge

[23], The latter reference lists the band head measurements of Angstrom

and Thalen which date from 1875. Intensities are primarily those of Pearse and Gaydon [187]. Duffendack and Pox [58] list a band at 4209.0 A as pre- viously given, but this band is not further identified.

Table 7. Band heads and origins of the A'n

system of CI3 016 (V)

Xff (TH v'—v" Ref. Ref.

A

6559. 4 cm-1 15241.

0

0-5 157b cm-1 15246.

8

157b

6038. 08 16556. 98 0-4 157a 16563.

6

157b

5583. 06 17906. 34 0-3 157a 17913.

5

157b

5182. 71 19289. 55 0-2 56 19297. 00 56

4828. 50 20704. 57 O-l 56 20712. 50 56

4396. 06 22741. 28 1-1 56 22749. 76 56

Data from McCulloh [157a], McCulloh and Glockler [157b], and Douglas and Miller [56].

Table 8. Band heads and origins of the C1 ^—>A'n

Herzberg system (F)

X*r <JH I v'—v" Ref. <TQ Ref.

A

5705.

9

cm-1 17520.

9

0 0-7 97 cm-1 17526. 6 (*) 5318.4 18797.

4

1 0-6 97 18803.

4

(*) 4972. 8 20103.

8

2 0-5 97 20110. 2 C)

4661. 68 21445. 47 5 0--i 224 21452.

3

(*) 43S0. 27 22823. 22 7 0-3 224 22830. 5 121

4125. 03 24235. 42 7 0-2 224 24243.

2

121 3893. 20 25678. 55 7 0-1 224 256S6.

1

121

3680. 16 27165. 01 4 0-0 224 27174. 17 224

Data from Johnson and Asimdi [121], Schmid and Gero [224], and Herzberg

[97]. Intensities are those of Herzberg [97].

“ Calculated from the band heads.

43
Table 9. Band heads of the Hopfield-Birge systems

Transition X a v'-v" Ref.

(a) Bi2+<—>X'2+ A

1209.80 cm-1 82658. 3 0-2 209

1179. 59 84775. 2 0-1 209

1150. 52 86917. 3 0-0 209

1123. 6 89000 1-0 255

1098.9 91000 2-0 255

Data from Read [209] and Tanaka, Jursa, and LeBlanc [255]. The identification of the 2-0 band is uncertain.

(b) C>2+<—>X1 2+

’ a 1113. 89 89775. 9 0-1

1087. 91 b 91919.1 0-0 1063.09 b 94065. 5 1-0

a Band head from data of Read [209].

*> Band origins from [276].

(C) E ' ER—

>

X>2+ a 1076. 08 92930. 03 0-0

b (1053) 94967 1-0

Data from Tilford, Vanderslice, and Wilkinson [257]. a origin: b head. The 0-0 band head has been observed 1255] at 1076.1 A, 92928 cm"1

.

(d) F(i2D‘ X'2+ 1002. 7 99730 0-0

a (985.8) 101450 1-0

a (973.1) 102770 -2-0

209 276

257 257

104

117 117

Data from Hopfield and Birge [104] and Jevons [117]. a

1-0, 2-0 band positions inferred from vibrational constants listed by

Jevons [117] and Herzberg [99],

(e) G(‘II)< X'2+ 949. 97 105266 0-0

Data from Hopfield am Birge [104],

(f) b3 2+<—>X'2+ 1 193.

1

83812 0-0

a

(1134. 6) 88137 2-0

Data from Hopfield and Birge [104] and Tanaka, Jursa, and LeBlanc [255], Herzberg [99 1 lists (1192.9 A), 83831 cm-1 for 0-u.

a Uncertain identification of a very weak band. No other observation of

b, v=2 has been reported.

Table 10. Band heads and origins of the a' 32+ <—X>2+

Hopfield-Birge system ( R)

Xh <TH (TO I v'-v"

A CTO-1 cm-1 1806. 3 55363 0 0-0

1767. 7 56570 0 1-0

1731. 4 57756 57750. 16 1 2-0

1697. 2 58922 58916. 49 2 3-0

1664.8 60068 60062. 64 4 4-0

1634.2 61192 61187. 65 8 5-0

1605.

2

62299 62293. 64 20 6-0

1577. 7 63384 63379. 44 40 7-0

a (64446. 9) 8-0

1526.

8

65495 65492. 28 80 9-0

1503. 2 66523 66520. 39 100 10-0

a (67529. 5) 11-0

1459. 4 68522 80 12-0

1439. 0 69494 69491. 25 100 13-0

14-0

15-0

1383. 2 72298 72295. 14 50 16-0

1366.2 73194 50 17-0

18-0

1334.5 74934 74932. 04 30 19-0

1319. 7 75776 75773. 91 20 20-0

21-0

1291. 9 77408 20 22-0

1279. 0 78186 78184.

8

10 23-0

Data from Herzberg and Hugo [101].

a Data from Gero and Lorinczi [80].

44
Table 11. Band heads of the a

3 n — X‘2+ Cameron

system (R)

Table 11. Band heads of the a3 II — X*Z+ Cameron system

( R) —Continued

(a) Emission (b) Absorption *

Branch X a 1 v'—v

Ref. X <r I v'—v" Ref. Branch X <r I v’-v"

A cm- A cm-i A cm-1 Ri 2582.

2

38745 1 4-8 2415.3 41390 1 2-5 Ri 2064.4 48440 1

'

Qa 2580.

2

38745 2 2413.

5

41421 2 Q2 2063.

2

48468 4 R* 2579.

1

38762 2 2412. 55 41437. 36 2 201 r2 _ 2062. 6 48482 5 0-0 Qj . 2577. 7 38783 3 2411.4 41457 1 Qj 2061.7 48504 1 Ra 2575.

3

38819 0 2409. 2 41495 1 Rs ' 2060.

6

48530 2

2560.

2

39048 1 3-7 2394.

8

41744 1 1-4 1994.2 50145 1 2558.

2

39078 2 2393.

1

41774 2 1992. 7 50183 5

2557.

1

39095 2 2392. 09 41789. 86 2 201 1992.

1

50198 5 i-0

2555.

9

39113 1 2391. 1 41809 1 1991.

3

50218 1 2553.

3

39153 0 2388.8 41849 1 1990. 2 50246 3

2538.

6

39380 1 2-6 2374. 96 42093. 18 0 0-3 201 1929. 7 51822 1 2536. 7 39409 2373.

3

42123 1 1928.

2

51862 3

2535.

6

39427 2 2372. 37 42139. 06 1 201 1928. 0 51867 5 2-0

2534. 5 39444 1 2371. 2 42160 0 1927. 4 51883 1 2531.

9

39484 0 2369. 0 42199 0 1925.

8

51926 2

2517.

8

39705 1 1-5 1-3

2516.

2

39731 2 2280.5 43837 0 1868.2 53527 3

2514.

9

39751 2 2279. 65 43852. 82 0 201 1867.

8

52539 3 3-0

2513.

7

39770 1 2278. 5 43875 0

2510.

9

39814 0 2277. 0 43904 0 1866.

1

53588 1

2497. 5 40028 1 0-4 0-2

2495. 7 40057 1 2261.

2

44211

2494. 4 40078 1 2260. 07 44228. 94 201 1812.8 55163 1 • 4-0

2492.

9

40102 1 2259. 5 44244

2491 40132 97 2257. 7 44279

2457.

8

40674 1 4-7 O-l

2456.

0

40704 2

2455. 40721 2 2157. 09 46344. 40 201 b 1765.

6

56638 0 ' 5-0

2453.9 40739 1 2451.8 40774 0

2436.

2

41035 0 3-6 0-0

2434. 5 41064 1 a All vacuum wavelengths.

2433. 4 41082 1 2061. 77 48486. 40 201

b Possibly incorrect branch designation.

2432. 4 41099 0 Data taken from Tanaka, Jursa, and LeBlanc [255].

2430.

3

41135 0

Most of the data are from Cameron [39] supplemented by data from Rao

[201] and Herzberg [97]. Intensities are from Cameron [39], Wavelengths

of Cameron [39] are uncertain by 0.5 A [119],

Table 12. Band origins of the a3 n — XJ 2+ Cameron system

v'-v" Ref.

cm"1 50188.

3

1-0 79

48473. 97 0-0 201

46330. 59 0-1 201

44213. 85 0-2 201

43838. 19 1-3 201

42123. 58 0-3 201

41774. 18 1-4 201

Data for 1-0 band from Gero, Herzberg, and Schmid [79]; all other data from Rao [201].

45
Table 13. Band heads of the b

3 2+ —>a3n Third Positive

system (V)

Branch X (7 I v'-v

X a I V'-V"

A cm—1 A cm—1 03 - .... 3134. 35 31895.

3

7 P3 3131. 47 31924. 6 10 P2 1-7 3129. 51 31944. 6 9 0-2 Pi 3127. 68 31963.

3

5

b 3825.

1

26136 — 3124. 94 31991.

4

5

3699. 54 27022. 70 8079. 90 32459.

2

8

3696. 48 27045. 06 ... 3078. 40 32475. 0 2

3693. 59 27066. 26 1 0-5 3075. 73 32503.

2

4 1-3

3690. 83 27086. 50 — 3073. 49 32526. 9 6

2977. 38 33576. 8 7

2974. 49 33609. 5 10 1-6 2972. 86 33628.

1

9 0-1

2971. 16 33647.

1

5

b 3612.

7

27672 — 2968. 57 33676.

5

7

3493. 31 28618. 0 5 2930. 76 34110.

9

3

3490. 44 28641. 6 4 2929. 25 34128. 5 3

3487. 73 28663. 8 9 0-4 1-2

3485. 36 28683. 2 3 2924. 86 34179. 7 2

3482. 23 28709. 0 5

3419. 17 29238. 5 6 2833. 08 35287.

0

7

3417. 49 29252.

9

6 2830. 15 35323.

4

10

3414. 65 29277. 2 4 1-5 2828. 73 35341. 4 9 0-0

3411. 52 29304.

1

3 2827. 28 35359. 2 8

2824. 86 35389. 5 8

3305. 66 30242. 5 7 2793. 07 35792. 9 6

3302. 76 30269. 7 8

3300. 51 30289. 7 6 0-3 2789. 11 35843.

3

6 1-1

3298. 43 30308. 7 5 2787. 37 35865. 5 8

3295. 52 30335. 6 5 2785. 80 35885.

8

6

3242. 14 30835.

0

8

b 2665. 5 37515

3240. 69 30848. 8 6

3237. 74 30876. 9 6 1-4 2661. 87 37556. 4 8 1-0

3235. 18 30901.

3

8 2660. 42 37577.

0

8

2658. 80 37599. 8 6

Table 14. Band heads of the c

3 2+ —>a3n SA system (V)

Branch X <7 I v'-v"

A cm~l Os 2711. 40 36871. 0 2 02 2710. 25 36886.

0

2 P3 bO-4 P2 2708. 09 36915.

0

0

Pi - 2706. 59 36935.

9

5

2596. 99 38494. 66 2

2595. 97 38509. 66 1 2595. 74 38513. 16 •0-3

2594. 13 38536. 98 0

2592. 55 38560. 60 5

2489. 98 40148. 77 2

2489. 09 40163. 09 0

2488. 40169. 09 0 » 0-2

2487. 29 40192. 33 1 2485. 86 40215. 47 5

2389. 81 41831. 64 2

2389. 00 41845. 71 1 2388. 41854. 18 1 »0-l

2387. 20 41877. 25 2

2385. 93 41899. 61 5

2295.

9

43542.

5

0

b 0-0

2292. 22 43612.

4

3

»Data from the fine structure work of Gero [77].

bData from vibrational measurements of Asundi [4], For the 0-3, 0-2, and 0-1 bands, both authors’ data agree

to within 0.3 A. These bands appear double-headed under low dispersion.

Band heads mostly from Asundi [4], “Data on 0-5 band from Beer [16].

b Data from Duflendack and Fox [57].

46
Table 15. Band, heads of the a' 3 2+ —>a 3 n Asundi system (

R

)

X a / v’—v" Ref.

A cwr1

4-0

8592 11636.

0

4

8281.0 12072.

5

4

6-1

8222.

5

12158.

5

4

7888.

0

12674. 0 4

5-0

7833.9 12761.

8

4

7598.

0

13157.7 4

7574 13200 ' 7-1 158

7552.

5

13237.

0

4

7359.

0

13585.

1

4

7337 13626 i 9-2 158

7314.

0

13668.

4

4

7257. 13776.0 4

7229 13829 ' 6-0 158

7210.

4

13864.

5

4

7158 13967 158

7134 14014 * 11-3 158

7116.5 14048.

8

4

7007 14267 • 8-1 158

6988 14306 158

6841.

5

14612.7 4

6820 14659 • 10-2 158

6804.

0

14693.

2

4

6726.

3

14862.

9

4

6704 14913 7-0 158

6685. 7 14953.

2

4

6551.0 15260.

6

4

6530 15309 9-1 158

6513.

5

15348.

5

( 4

X a I v'—v" Ref.

A cm~l 6445.

3

15510.9 68

6 ' 16-5

6405.

0

15608.

5

68

6397 15627 158

6 t 11-2

6366.

9

15702.

0

4

6275.

0

15931.

8

4

6257.

8

15975.

6

6 > 8-0 68

6244.

7

16009.

2

68

6159. 5 16230.

6

5 15-4 68

6135.

0

16295.

4

68

6127.

5

16315. 4 68 6119.0 16338.

0

6 . 10-1 68

6105.2 16375.

0

4

5888. 7 16977.

0

5876.

2

17013.

1

5 > 9-0 68

5869. 4 17032.

8

5855.

8

17072.

4

5836. 5 17128.

8

5 t 16-4 68

5812.

8

17198.7

5779.

6

17297. 4 68

5773.

5

17315.7 68

5769.

7

17327.

1

5 11-1 68

5761 17354 158

5746.

0

17398.

6

68

5 l 20-6 68

5711.

1

17504.

9

5071.

4

17627.

4

6 i 13-2 68

5058.8 17666.

7

5 \ 19-5 GS

5486.

3

18222. 2

47
Table 15. Band heads of the a'3 2+ —>a3 n Asundi system (

R

)—Continued

X a I tf—v" Ref. X a I v'—v" Ref.

A cm-1 A cm-1

5

' 12-1 68 6 19-3 68

5447. 4 18352.

3

4671.

0

21402. 7

| 4667.

1

21420. 6

5394.

8

5388.

3

5382.

6

5376.4

5369.9

18531.

2

18553.

6

18573. 2

18594.

6

6 14-2 68 8 > 14-0 68

18617.

2

4541.

2

22014. 5 )

5256.

2

19019.

9

4342.

0

23024.

4

7 * 11-0 68 • 19-2 68

5237.

8

19086.

7

4330.

8

23083.

9

5095.

7

19618.

9

5084.

1

19663.

7

6 ' 17-3 68 7 1 20-2 68

4172.0 23962.

6

5057.4 19767.

5

5045.

2

19815.

3

5 ' 21-5 68 5 > 25-4 68

5039. 0 19839.

7

5033.

8

19860.

2

4069. 5 24566.

1

4998. 5 20000.

4

4993.

2

20021. 8

4990. 4

4986. 4

20032. 9

20049.

0

1 \ 12-0 68 4043.

8

4038.

9

24722.

2

24752.

2

7 > 19-1 68

4979. 0 20078.

8

4034.

9

24776. 8

4872.

8

20516. 4 3925.

7

25466. 0

3922. 6 25486.

1

6 i 18-3 68 8 | 22-2 68

4858.0 20578. 9 3915.9 25529.

7

4853. 6 20597.

5

|

8 > 13-0 68 8 \ 20-1 68

4747. 6 21057.

4

3902.

9

25614. 7

4700.

8

21267.

0

4693. 5 21300.

1

7 > 17-2 68

4683.7 21344.

7

I

Data from Garg [68] Asundi [4], and McLennan, Smith, and Peters [158], Intensities from Garg [68]. Pearse and Gaydon [187] use;/ three units less than that used here. Wallace [266] lists vacuum wavelengths for these bands. Rosen et al. [213], p. 66 list the band at 6685.7 A as 7-1; it is the TR3i head of the 7-0 band.

48
Table 16. Band heads of the d3 A,—>a3Il Triplet system (

R

)

(a) Identified bands

X o I v'-v" Ref. X <J I v'-v" Ref. X a I v'-v” Ref.

A cm'1 A CTO-1 A cm~l

(7602. 1) 13326 5140. 3 19448 4494. 4 22244

7616 13303 1-0 7 5128.

1

19495 2 160 4478. 8 22321 15-3 96

(7483) 13360 5116.2 19540 4462.9 22401

5070. 9 19715 4466 22385

(7231. 3) 13825 3-1 7 5052. 7 19786 8 7-0 96 4452.2 22455 19-5 96

(7200) 13885 5033 19864

6964.

3

14355 4996. 9 20007

6925. 2 14436 2-0 7 4979. 0 20079 6 9-1 96 4460.4 22413 17-4 96

6901 14487 4959. 0 20160 4444.7 22492

6464. 6 15465 4935. 5 20256 4454. 5 22443

6433.1 15540 10 3-0 96 4917.

2

20331 2 11-2 96 4445. 5 22488 1 160 6401.0 15618 4897. 5 20413 4437 22531

6383.1 15662 4880. 8 20483 4405.

0

22695

6348.

7

15747 1 160 4869.

3

20531 13-3 96 4390.

9

22768 10-0 96 6319.8 15819 4374. 0 22856

6037. 0 16560 4823.

5

20726 4369. 9 22877

6010. 5 16633 8 4-0 96 4806.

7

20798 8 8-0 96 12-1 96 6982 16712 4787 20884 4339. 4 23038

5836.

9

17128 4764. 8 20981 96 4343. 8 23015

5812.

1

17201 2 160 4747.

5

21058 5 10-1 96 4328. 7 23095 14-2 96

5779 17299 4729.

1

21140 160 4314.

1

23173

5670.

5

17630 4716.6 21196 96 4326 23110

5647.

6

17702 6 5-0 96 4702 21262 219 4312 23185 16-3 96

5624 17776 4678 21371 219 4297 23266

5554.

1

18000 4680. 3 21360 4227. 2 23650

5532. 5 18070 5 7-1 96 14-3 96 4213. 7 23725 11-0 96 5508 18150 4646.7 21515 4198.

9

23819

5428.

3

18417 4602. 6 21721 4201.

5

23794

5414.

5

18464 1 160 4586. 4 21797 7 9-0 96 4188.4 23869 13-1 96

5402.

5

18505 4571 21871 4174. 6 23948

5351.

2

18682 4556. 5 21941 4182. 5 23902

5330. 5 18755 5 6-0 96 4541.0 22015 5 11-1 96 4171 23968 15-2 96

5308 18834 4524. 0 22098 4157 24049

5258.

3

19012 4520. 7 22114 4036. 4 24768

5238.

4

19085 5 8-1 96 4505. 5 22189 13-2 96 4023. 7 24846 16-2 96

5216 19166 4488. 4 22273 4011 24924

Data from Herman and Herman [96, 92] supplemented by data from Merton and Johnson [160] and Asundi [7], Intensities are from Merton and Johnson

160]. For the shortest wavelength heads in each triplet, Herman and Herman [96, 92] list values which are the average of double heads reported by Merton

and Johnson [160]. Numerous other band positions of reference 96 are exactly those given in ref. [160].

49
Table 16. Band heads of the d

6 Aj —>a3 n Triplet system

( R) —Continued

(b) Unassigned bands »

X a X a X <T

A cm~l A cm-' A cm-i

6613 15118 4460.

1

22415 4074 24540

6557 15247 4441. 7 22508 6515 15345

6323 15811 4460 22415 4055 24655

6282 15914 4444 22495 4049 24690

6248 16001 4437 22531 4034 24780

6141 16279 4428 22575 4034 24780

6122 16330 4416 22640 4023 24850

6105 16375 4406 22690 4010 24930

5889 16976 4398 22730 3928 25450

5860 17060 4378 22835 3919 25510

5839 17121 4370 22875 3912 25555

5804 17225 4314 23175 3896 25660

5777 17305 4297 23265 3893 25680

5752 17380 4288 23315 3884 25740

5157 19386 4240 23580 3885 25735

5138 19457 4229 23640 3875 25800

5112 19556 4213 23730 3870 25830

5098 19610 4344 23015 3804 26280 4339 23040 3795 26345

4331 23085 3788 26390

4888 20453 4188 23870 3778 26460 4870 20528 4184 23895 3767 26540

4850 20613 4176 23940

4663 21439 4161 24025 3755 26625

4647 21513 4156 24055 3740 26730 4625 21616

4491 22260 4115 24295 4480 22315 4108 24335 4463 22400 4088 24455

a Data from Sato [219] who assigned quantum numbers to these bands. Those assignments are considered uncertain.

Table 17. Band origins of the d

3 A,—>a3n Triplet system (R)

(TO v'—v"

cm~l 15538. 5 3-0

16627.

4

4-0

19785. 8 7-0

21794. 4 9-0

Data from Gero and Szabo [82] with revised v' numbering of Carroll [40].

Table 18. Band heads and origins of the e

3 2~<—X‘S+

system ( R

)

X <TH (TO I v'—v"

A

1542.

8

cmr1 64816 cm~l 50 1-0

1517.7 65891 65877. 82 30 2-0

1493.

7

66946 66933. 26 20 3-0

1471.0 67982 67970. 31 50 4-0

1428. 9 69992 69986. 39 30 6-0

1390.

1

71925 71926. 47 25 8-0

1355. 2 73792 73792. 28 20 10-0

1338. 5 74709 20 11-0

1308.

1

76448? 20 13-0

1293. 6 77303? 15 14-0

1241. 9 80523? 5 18-0

Data from Herzberg and Hugo [101], All v' values are one unit larger than

in the original paper [238a],

(?) Band heads seen at expected positions. Bands with v' up to 23 have been observed [238a] but detailed analysis is not yet available.

Table 19. Band heads of the C1 S+ —>a

,32+ Knauss

system (V)

X a v'—v"

A

3253

cm-i

30732 0-5

3138 31858 0-4 3028 33015 0-3 2925 34178 0-2

Data from Knauss [130].

Table 20. Band heads of the Kaplan system ( R

)

8

Transition X <T v'—v

Ref.

K-aTI

^4 2750 cm-i 36350 0-3 125 2630 38010 0-2 125 2518 39700 0-1 125

?—X*2+ 8

(2575) 38820 126

8 The reality of this band as representing a transition in CO is highly

questionable.

50
Table 21. Band heads of the d3Ai<—X‘2+ system ( R

)

Table 23. Band heads of the Eo‘2—>X’2+ system ( R

)

X a 1 v'-v"

A

1617.

5

cm-1 61824 0+ 1-0

1588.

8

62941 1 2-0

1561.3 64049 3 3-0

1535.

2

65138 3 4-0

1486. 6 67268 4 6-0

1464.

2

68297 5 7-0

1442.

8

69310 6 8-0

1402. 71286 10 10-0

1384. 2 72244 10 11-0

1366. 6 73174 9 12-0

1350.

0

74074 7 13-0

1334. 8 74918 5 14-0

1319. 6 75781 5 15-0

1305. 3 76611 3 16-0

1291. 9 77405 3 17-0

1279. 0 78186 2 18-0

1254.

4

79719 1 20-0

1243.4 80425 0+ 21-0

1232.

4

81142 0+ 22-0

Data from Tanaka, Jursa, and LeBlane [255]. Their v' numbering has been raised one unit [40]; the upper state had formerly been considered

an, [40, 171]. a Band intensities are almost 103 times weaker than the A-X bands.

Table 22. Band heads of the e

3 2~ —>a3 n Herman system (R)

( )= interpolated. See also ref. [96], The intensities are those given by Merton and Johnson

[160], Revised v' quantum numbering is that suggested by Simmons et al., [238a].

X <7 I v

f —

v"

A cm-1 1309. 13 76386.

4

1 0-7

1276. 07 78365.

9

2 0-6

1244. 16 80375. 5 3 0-5

1213.31 82419. 2 4 0-4 1183.62 84486. 6 5 0-3

1154.91 86586. 9 4 0-2

1127. 23 * 88713.0 2 0-1

1100. 49 90868.

6

2 0-0

Data from Tschulanovsky [260], The formula fitting the term values of these bands deviates considerably from that of the ground state. This makes

the reality of the Eo state somewhat uncertain. In this report v'=0 has been

assumed.

a Band also observed in absorption by Tanaka, Jursa, and LeBlane [255].

Table 24. Band heads of the 1 n—»X1 S+ system (

R

)

X a / v'—v"

A cm-1 1132. 52 88299 1 0-5

1106. 44 90380 2 0-4

1081. 77 92441 0-3

1057. 60 94554 4 0-2

1034. 65 96651 3 O-l

1011. 75 98839 1 0-0

Data from Tschulanovsky [260],

Table 25. Band heads of the f

3 2+—>a3II system ( R)

X a v'-v

A cm-1 2979. 95 33547. 82 0-1

2670. 14 37440. 15 ?-0

Data from Gero [78]. The v' numbering is uncertain.

51
Table 26. Band heads of Tanaka systems ( absorption

)

(a) P<—X*2+

X <J I v'-v"

A cm1

791. 08 126410 5 0-0

781. 50 127959 6 1-0

772. 32 129480 6 2-0

763.68 130945 5 3-0

755. 24 132408 4 4-0

747. 30 133815 4 5-0

739. 52 135223 2 6-0

732. 00 136612 3 7-0

(b) Q<-Xi2+

776. 77 128738 2 0-0

767. 60 130276 5 1-0

758. 80 131787 3 2-0

750. 22 133294 3 3-0

742.09 134755 3 4-0

» 734. 15 136212 2 5-0

Table 26. Band heads of Tanaka systems ( absorption) Continued

(c) R«—X>2+

776.00 128866 3 0-0

766. 71 130427 3 1-0

757. 86 131950 3 2-0

749. 48 133426 2 3-0

741. 40 134880 2 4-0

733. 36 136359 4 5-0

(d) 8«- X12+

690. 92 144735 2 0-0

683. 21 146368 1 1-0

675. 73 147988 1 2-0

668.44 149602 0 3-0

(e) T<- X‘2+

647.83 154362 3 0-0

642. 27 155698 2 1-0 636.88 157016 1 2-0

Data taken from Tanaka [254], “Misprint in original paper corrected.

Table 27. B2 2+ (CO+

) <—X!2+ “/3” Rydberg series

n X Sharp series v'-v" n

Diffuse series I v'-v"

c

r

I X •7

A cm-1 A cm-1 4 » 725.

9

137760 0-0 4 a 716. 7 139530 0-0

[ 672. 44 148712 5 0-0f 670. 67 149105 4 0-0

5

1 664. 87 150405 4 1-0 5 \ 663. 32 150757 2 1-0

! 657. 67 152053 3 2-0 I 656. 40 152346 1 2-0

1 650. 81 153655 0 3-0

[ 654. 40 152812 4 0-0f 653. 58 153004 2 0-0

6

647. 22 154507 2 1-0 6

| 646. 53 154672 1 1-0

I 640. 35 156165 0+ 2-0 [ 639. 84 156289 1 2-0

l 633.80 157779 0+ 3-0

645. 91 154820 2 0-0

f 645. 40 154943 2 0-0

7

j 639. 13 156463 2 1-0 7 \ 638. 56 156602 i 1-0

l 632.43 158120 0+ 2-0 631. 98 158233 0+ 2-0

i 641. 26 155943 2 0-0 8 640.81 156053 1 0-0

8

j 634.41 157627 1 1-0

1 628. 05 159223 2-0

9

1 638. 42 156637 2 0-0 9 638. 05 156728 1 0-0

\ 631. 72 158298 0+ 1-0

10 636. 61 157082 1 0-0

11 635. 26 157416 1 0-0

12 634. 41 157627 0 0-0

Data taken from Tanaka [254],

» Data for «=4 taken from Huffman, Larrabee, and Tanaka [107]; wave-lengths to ±0.5 A. The sharp series is possibly (>2)<—Xi2+ [254],

The diffuse series is possibly (

i n)«—X>2+ [254],

<r a,!sharp) = 158692±30 cm-i=19.6748 eV=630.16 A.

<r a, (diffuse) =158745±30 cm-i= 19.6814 eV=629.94 A,

52
Table 28. A2n,(CO+

) <—X‘2+ “a” Rydberg series

11 X <T I v'-v"

A cm~'

810.80 123335 3 0-0

800. 94 124856 3 1-0 791.64 126320 4 2-0

5

782. 47 127800 3 3-0

773. 76 129239 3 4-0

784. 70 127436 3 0-0

775. 11 129014 3 1-0 766.09 130533 4 2-0

757. 35 132039 3 3-0

772. 61 129431 6 0-0

7 763.50 130975 7 1-0

754. 70 132503 3 2-0

765. 35 130659 2 0-0

8 756. 37 132210 2 1-0

747. 74 133736 2 2-0

761. 48 131323 1 0-0

9 752. 60 132873 2 1-0 744.03 134403 1 2-0

Data from Tanaka [254],

o-oa = 133380 cm-i = 16.537 eV = 749.74 A.

Table 29. X2 2

+ (CO+

) <—X‘2+ Rydberg series

n

0-0 series 1-0 series

X (T X <r

6 A938.3

cm~>

106576 A919.5

cm-'

108761

7 918.7 108849 900.7 111020

8 908.4 110084 890.8 112265

9 902.0 110865 884.8 113026

10 898.0 111357 880.8 113538

11 895.2 111707 878.1 113882

12 893.2 111957 876.2 114129

13 891.7 112145 874.8 114312

14 890.6 112284 873.8 114451

Data from Takamine, Tanaka, and Iwata [253], „„ (0-0) = 113029 cm-1 = 14.013 eV=884.73 A (±0.004 eV).

o-oo d-0) = 115190 cm-i = 14.281 eV=868.13 A,

Table 30. Band heads of the B2 2+—>X2 2+ First Negative system of CO+

( R)

X a / v'-v" X a / v’-v"

A

3152. 71

cm~'

31709.

6

1 8-13 A

a 2325. 17

cm-'

42994. 31 9 1-2

3107. 45 32171.4 2 7-12 a 2299. 80 43468. 68 10 0-1

3064. 02 32627.

4

3 6-11 2298. 18 43499.

2

3 4-4

3022. 97 33070.

4

2 5-10 2293. 67 43584.

8

1 10-8

« 2984. 16 33500.

5

2 4-9 2268.58 44066. 8 3 3-3

2947. 56 33916.

5

1 3-8 2255. 75 44317.

4

1 9-7

2938. 54 34020.

6

1 7-11 2254. 28 44346.

3

2 6-5

2913. 18 34316. 7 1 2-7 2240. 43 44620.4 4 2-2

2897. 16 34506.

4

3 6-10 2222. 66 44977.

2

4 5-4

2882. 23 34685.

2

2 1-6 2220. 27 45025.

6

0 8-6

2874. 46 34778.

9

0 9-12 2214. 46 45143.

7

5 1-1

2858. 08 34978.

3

4 5-9 « 2189. 85 45650. 99 10 0-0

2820. 82 35440.

2

5 4-8 2185. 13 45749.

6

4 7-5

2785. 81 35885.

6

5 3-7 2164. 34 46189.

0

5 3-2

* 2752. 89 36314. 67 6 2-6 2154. 15 46407. 4 4 6-4

2745. 10 36417.8 1 6-9 2137. 77 46763.

0

6 2-1

» 2722. 32 36722. 43 7 1-5 2123. 77 47071. 2 3 5-3

2707. 95 36917.

4

3 5-8 2112. 38 47325.

0

8 1-0

a 2693. 87 37110. 35 2 0-4 2095. 27 47711. 4 5 4-2

a 2672. 34 37409. 27 7 4-7 2090. 95 47809.

6

4 7-1

b 2638. 72 37885.

9

8 3-6 2067. 92 48342.

3

1 3-1

a 2607. 16 38344. 46 8 2-5 2067. 81 48344.

8

1 9-5

» 2577. 78 38781. 52 10 1-4 2061. 03 48503.

9

3 6-3

» 2550. 32 39198. 99 7 0-3 2042. 29 48948. 9 4 2-0

2534. 79 39439.

2

1 4-6 2034. 32 49140. 6 2 8-4

a 2504. 47 39916. 54 10 3-5 2032. 27 49190.

3

1 5-2

b 2474. 21 40404.7 10 2-4 2004.73 49865.

9

0 4-1

a 2445. 82 40873. 68 10 1-3 2003. 11 49906.

2

0 7-3

a 2419. 48 41318. 69 8 0-2 1983. 92 50405. 3 0 9-4

2412. 43 41439.

4

4 4-5 1975. 28 50625. 7 0 6-2

2381. 52 41977.

1

5 3-4 1831. 05 54613.

4

0 9-2

2362. 46 42315.

8

1 6-6 1802. 83 55468.4 0 8-1

» 2352. 56 42493. 86 6 2-3

Most of the band heads are taken from Biskamp [24],

» Data from Rao [202a],

b Data from Schmid [237], Intensities are those of Biskamp [24].

» Listed by Biskamp as uncertain 8-12 or 4-9. Biskamp’s measurements are probably good to

0.05 A; Rao claims accuracy to 1 cm-1. Johnson

[118] has observed an additional band (unclassified) 2883.6 A 34668.7 cm-

' (1=2).

53
Table 31. Band origins of the B2 2+—>X2 2+ First Negative system of C0+

v"

0 1 2 3 4 5 6 7

45633. 44 43449. 62 41295. 97

42975. 40

39172. 76

40852. 15

42478. 75

37079. 87

38759. 31

40385. 72

36696. 77

38323. 19

39898. 85

36291. 06

(37866. 7) 37392. 19

Data mostly from Rao [202a], Data of ref. [45] agree with that of ref. [202a] within 0.5 cm-'

.

( ) = Origin of 3-6 band from Coster, Brons, and Bulthuis [45]. Misprint in ref. [202a], 2-5 origin should be 38323.19 cm-1

.

Table 32. Band heads of the A2 nt—> X2 S+ Comet Tail system of CO+ ( R)

X <7 I v'—v" X <J I v'—v" X <7 I v'—v" X <T I v'—v"

A cm-1 A cm-1 A cm-1 A cm-1

TT J 8477. 69 11792. 43 5075. 56 19696. 76 4274. 38 23388. 62 3526. 95 28345. 01

H3/2 —

[8465. 00 11810. 10 a 0—4 5071. 69 19711. 79 2 b 1_1 4271. 95 23401. 95 10 c 2. 0 3525. 64 2S355. 54 4 7-1

TT J 8388. 40 11917. 95 5043. 43 19822. 25 4251. 63 23513. 79 3511. 72 28467. 93

II1/2 —2

- [8373. 97 11938. 49 5039. 19 19838. 92 4248. 92 23528. 75 3510. 27 28479. 69

7199. 91 13885. 23 4913. 64 20345. 82 3429. 20 29152. 96

7191. 74 13901. 01 a 0-3 4909. 96 20361. 10 3 >= 0-0 2 5-2 3497. 85 29164 44 5 6-0

7135. 54 14010. 49 4883. 53 20471. 27 4246. 16 23544. 06 3414. 58 29277. 78

7125. 55 14030. 13 4879. 44 20488. 45 4244. 10 23555. 49 3413. 29 29288. 85

6246. 61 16004. 25 4868. 98 20532. 45 4153. 82 24067. 44 3306. 98 29691. 68

6239. 30 16023. 01 5

a 0-2 4865. 83 20545. 74 3 3-2 4151.92 24078. 45 2 7-3 3366. C2 29700. 15 4 8-1

6196. 38 16133. 98 4839. 55 20657. 31 4132. 53 24191. 43 3352. 94 29816. 00

6189. 27 16152. 52 4836. 58 20669. 99 4130. 39 24203. 96 3351. 71 29S26. 94

5905. 66 16928. 22 4714. 56 21204. 96 4140. 42 24145. 33 3315. 50 30152. 69

59C0. 40 16943. 31 3 2-3 4711. 47 21218. 84 6 b 2-1 4138. 92 24154. 08 3 4-1 3314. 18 30164. 70 2 10-2

5862. 31 17053. 40 4686. 90 21330. 09 4119. 38 24268. 65 3302. 06 30275. 41

5856. 51 17070. 29 4683. 51 21345. 53 4117. 28 24281. 03 3300. 66 30288. 25

5700 17539 4019. 86 24869. 49 3275. 24 30523. 32 5695 17554 1 1 5-3 4017. 78 24882. 38 9 C 3-0 3273. 91 30535. 72 3 7-0

5659 17666 4667. 98 21416. 55 3999. 71 24994. 75 3261. 53 30651. 15 5654 17682 4664. 54 21432. 34 3997. 45 25008. 92 3260. 35 30662. 71

5698. 59 17543. 33 4568. 75 21881. 71 3909. 90 25574. 7 3223. 47 31013. 52

5693. 59 17558. 74 3 1-2 4565. 97 21895. 02 8

b 1-0 3908. 00 25581.

3

5 5-1 3222. 42 31023. 62 2 9-1

5658. 09 17668. 91 4542. 91 22006. 16 3890. 53 25696.

2

3210. 67 31137. 15

5652. 60 17686. 07 4539. 62 22022. 11 3888. 55 25709.

2

3209. 64 31147. 14

5504. 46 18162. 04 3797. 70 26324. 27 3181. 34 31424. 21

5499. 86 18177. 23 5 0-1 5 4-2 3795. 96 26336. 37 8

c 4-0 3180. 26 31434. 88 9 11-2

5466. 74 18287. 36 4521. 00 22112. 80 3779. 77 26449. 19 3169. 07 31545. 87

5461. 42 18305. 17 4517. 99 22127. 53 3777. 87 26462. 46 3168. 03 31556. 23

5430. 51 18409. 36 3707. 10 26967. 59 3136. 77 31870. 69

5426. 44 18423. 17 1 3-3 1 6-3 3705. 31 26980. 62 6 6-1 318S3. 50 9 8-0

5393. 92 18534. 24 4381.

4

22817. 3 3689. 84 27093. 74 3124. 47 31996. 15

5389. 25 18550. 30 4378. 9 22830.

4

3688. 09 27106. 59 3123. 18 32009. 37

5248 19050 4406. 24 22688. 72 3602. 34 27751. 84 3094. 57 32305. 29 5244 19064 34 2-2 4403. 26 22704. 07 4 3-1 3600. 88 27763. 14 7

c 5-0 3093. 30 32318. 55 1 10-1 5214 19174 4381. 38 22817. 45 3585. 96 27878. 58 30S2. 71 32429. 57 5209 19192 4378. 93 22830. 22 3584. 33 27891. 25 3081. 46 32442. 73

Data of Baldet [9] supplemented by data of (a) Rao [202b], (b) Schmid and Gero [222], and (c) Coster, Brons, and Bulthuis [45]. Intensities are from Baldet

[9]. Head-forming branches are Qi, Ri, R2 , R21 , given in order of decreasing wavelength. Johnson [118] lists a double-headed band of intensity 2 (4139.0 A,

4123.2 A) which may belong to this system.

54
Table 33. Band origins of the A2 II; — X2 2+ Comet Tail

system of C0+ Table 35. Miscellaneous unclassified bands

3 4

0 16070.11 13946.74 11853.88 | a

1

23

4

5

21942.73 19758.78

21266. 74

0 23450. 59

24931. 68

26386. 23

29214. 02

30588. 61

910

11

29752. 85 31074.41

d

31484. 55

» Data from Rao [202b].

b Computed from the data of Schmid and Gero [222].

c Computed from the data of Coster, Brons, and Bulthuis [45], d Computed from the data of Bulthuis [34a],

Data compiled by Rao [202b],

Table 34. Band heads of the B2 Z+—>A2 nt

- Baldet-Johnson

system of CO+ (V)

X G I v'-v" Ref

A cm-* 4236. 28 23598. 96 3

4231. 42 23626. 09 9 0-1 34b

4212. 98 23729. 46 7

4209. 02 23751. 82 8

1 4201. 5 23794 1 4182. 6 23902 1 1-2 118

4179.

1

23922 1 J

3978. 13 25130. 36 4

3973. 31 25160. 84 9

0-0 34b

3957. 37 25262. 13 6

3953. 52 25286. 77 9

3729.

8

26803 3

3725. 0 26838 9 1-0 118 3711.3 26937 9

3707. 6 26964 9

3515.

8

28435 2 3511.7 28468 7 2-0 118

3500.

4

28560 3

3496. 7 28590 4

3331. 9 30004 1 3329. 0 30030 1 3-0 118 3317.9 30131 1 3314. 8 30159 1

Data from Johnson [118] and Bulthuis [34b], Measurements of Baldet [8] differ from the above by up to 1 A. Intensities are those given by Johnson

[118]. Head forming branches are Pi, Qi, P21 , and Q21 in order of decreasing

wavelength.

(a) Band heads observed together with the A>1I — X>2+ Fourtii Positive system (emission) b

X G I Ref.

A

2485.

8

cm~l 40216.

4

277

2299. 6 43472. 4 277

2209. 0 45255. 2 1 59

2098. 19 “ 47644. 9 89

2088. 0 47877 59 2064.0 48434 59 2042.3 48949. 5 1 90

2040. 0 49004 59

1953.

0

51203.

3

5 L

1933.

6

51717. 0 2 23

1837.2 54430. 7 1 L

1835. 47 54481.

9

89

1827. 6 54715. 7 1 90

1801. 9 55497. 0 2 L

1772.

9

56403. 8 4 90

1698.

8

58865.

1

1 L

1688. 5 59224.

2

1 L

1666. 7 59998.

8

1 L

1492.

6

66997.

2

7 90

1438. 7 69507 1 L

1405. 5 71149 1 L

1404.0 71225 1 L

1386. 4 72129 1 L

1363.

3

73350. 4 1 90

1343.

0

74460 1 L

1228. 2 81422.

6

1 90

1152. 9 86733.

3

3 90

1025. 7 97496.

3

90

L=Lyman (see ref. 23).

a Original measurement was in vacuum. Air wavelengths listed above.

b See sec. 3.1.

(b) Band heads observed in absorption a

X G I

A cm-1 1569. 5 63 715 1 1462.

3

68 385 3

1433. 69 769 2

1432. 3 69 818 2

1422.

4

70 304 8

1394.

3

71 721 1 1369.

5

73 019 2

1366. 6 73 174 8

1352.

4

73 943 1 1333. 2 75 008 1 1329.

3

75 228 3

1284.

8

77 833 1 1218.

6

82 061 0

1209. 2 82 699 0

1181.8 84 617 0 1135.3 88 082 1 1134. 6 88 137 1 1130.4 88 464 2

1115.4 89 654 1 1115.

1

89 678 1 1111.6 S9 960 1

Taken from Tanaka, Jursa, and LeBlanc [255],

» Intensities of these are approximately 103 times weaker than the strong

yl-.Y bauds. “The above bands are probably due to intercombination bands of CO.

The strongest two bands appeared even at a pressure of ~1 inm Ug” 1255],

55
Table 35. Miscellaneous unclassified bands—Continued Table 35. Miscellaneous unclassified bands—Continued

(c) Band heads observed with the a'32+—> a3 n Asundi system (e) Triplet bands observed in emission

X g I

A cm-1 6960 14364 1 6939 14407 0

« 6921 14444 0

6461 15472 2 6450 15500 2

6431 15544 2

6349 15747 i

6316 15829 i

6213 16091 0 6195 16137 0 6180 16177 1

5980 16716 2

5687 17579 1 5668 17636 2 5659 17666 3

Data from McLennan, Smith, and Peters [158],

a Band head given as 6982 A. It is assumed the correct wavenumber was

given.

(d) Band heads observed in emission by Tschulanowsky and Gassilewitsch

X a

A cm-1 1183.62 84486. 6

1154. 83 86592. 8

1123. 63 88997.

3

1107. 77 90271.

4

1083. 24 92315. 6

1066. 19 93791.

9

1057. 60 94553.

7

1052. 44 95017. 3

1034. 68 96648.

2

1032. 78 96826. 6

1024. 70 97589.

5

1018. 54 98179.

7

1011. 78 98835. 7

1008. 80 99127. 7 1007. 77 99229.

0

1007. 05 99299.

9

1005. 26 99476. 8

983. 84 101643

980. 65 101973

962. 47 103899 961.27 104029

952. 45 104992

» 948. 42 105439

* 945. 54 105760

943. 24 106017

* 935. 71 106871

Data from Tschulanowsky and Gassilewitsch [261], a Observed in absorption by Huffman, Larrabee, and Tanaka [107].

X G X G

A cm-1 A cm-i

(a) 4100 24383 (b) *4028 24819

4093 24425 4024 24844 4086 24467 *4021 24862

*4074 24539 4017 24887 4070 24563 *4013 24912

*4068 23575 *4007 24949

4063 24605 *4002 24980

4056 24648 3997 25012 4052 24672 *3995 25024 4046 24709 *3993 25037 4040 24745 3991 25049

*4033 24788 *3987 25074 4030 24807 *3983 25100

Data taken from Herman [95], ^Observed in comets; band positions less accurate than the

others.

(f) Unclassified absorption maxima

X G X G X G

A cm-1 A cm-1 A cmr1 1,000.0 100, 000 910.8 109, 790 788.7 126, 790

995.8 100,420 909.3 109, 970 776.1 128,850

990.9 100, 920 908.5 110, 070 771.2 129, 670

990.1 101,000 905.2 110, 470 768.8 130, 070

989.4 101,070 903.7 110, 660 760.5 131,490 986.0 101,420 903.2 110, 720 752.2 132, 940 985.5 101,470 900.1 111,100 749.2 133, 480 982.5 101, 780 898.8 111,260 745.6 134, 120 977.5 102, 300 895.4 111,680 737.3 135, 630 973.4 102, 730 894.7 111,770 728.3 137,310

972.9 102, 785 891.8 112,130 722.6 138,390 971.8 102, 900 889.7 112, 400 721.5 138, 600

970.5 103, 040 889.1 112, 470 719.2 139, 040

969.8 103, 110 888.5 112, 550 715.6 139, 740 968.9 103,210 888.1 112,600 714.5 139, 960

968.1 103, 295 885.4 112, 940 712.3 140,390

964.6 103, 670 867.9 115, 220 707.8 141,280

964.1 103, 720 864.5 115,670 705.2 141,800

960.4 104, 120 863.8 115, 770 702.1 142, 430 959.5 104, 220 861.4 116, 090 701.6 142, 530 956.3 104, 570 859.7 , 116,320 700.0 142, 860 954.1 104,810 858.3 116,510 698.8 143, 100 946.3 105, 670 857.2 116, 660 697.0 143,470 941.2 106, 250 854.5 117, 030 695.2 143,840 940.0 106, 380 853.2 117, 210 681.6 146, 710 933.2 107, 160 852.4 117,320 680.6 146, 930 931.9 107,310 851.6 117, 430 663.3 150, 760 930.1 107,515 849.4 117, 730 650.0 153,850 928.5 107, 700 846.0 118, 200 646.6 154,660 925.9 108, 000 841.4 118,850 634.4 157,630 924.5 108, 170 837.7 119,370 631.6 158, 330 922.6 108, 390 834.5 119,830 630.6 158, 580

921.1 108, 570 833.9 119, 920 605.8 165, 070 919.6 108, 740 832.5 120, 120 604.8 165, 340 917.5 108, 990 830.2 120, 450 604.1 165, 540 915.7 109, 210 821.4 121, 740 601.9 166, 140 913.6 109, 460 819.4 122, 040 912.2 109, 630 795.6 125, 690

Meas. of Huffman et al., [107]. Good to ±0.5 A.

56
Table 35. Miscellaneous unclassified bands—Continued Table 35. Miscellaneous unclassified bands—Continued

(g) Unclassified absorption bands 1

'

X

A cm~* 881.3 113470

871. 7

b 114720 848.6* 117840 844.3* 118440 839.3 119150

836.1 119600

827. 2* 120890

824.7 121260 817.8 122280 814.6 122760

807. 3* 123870 804.8* 124250

801.1 124830

797.7 125360

794. 8* 125820 791.6 126330

789.7 126630

786.3 127180

783. l

a 127700

779. 5* 128290

774. 0* 129200 765.8 130580 757.2 132070

750.4 133260

734. 2* 136200 725.7 137800

Data of Henning [91]. •These bands also seen in absorption by Huffman, Larrabee, and Tanaka

[107], » Observed also by Tanaka [254] as a closely spaced, triple-headed, and red degraded band.

b Seen in emission by Anand [2].

* See section 3.20.

(h) Emission and absorption bands of Anand

X a X a

A cm-' A cra-i

(a) 906.2 110350 (b) 897.7 111400 886.3 112830 880.7 113550 875.7 114190 *871. 6 114730

869.4 115020 866.5 115410 865.3 115570 862.5 115940 Emission series Absorption series

1 11 I 1 •Observed previously by Henning [91]. Data of Anand [2]; most of these bands have been observed recently, in absorption, by Huffman, Larrabee, and Tanaka [107], See section 3.20.

(1) Band heads observed together with the AJ n,—>X2 S+ Comet Tail system of CO-1-

X or I

A cm-1 6412 15591

] 6405 15608

1 6361 15716 6354 15734 J

6021 16604

] 6015 16621 5976 16729

2

5970 16746 1

5812 17201

5806 17219

i 5769 17329 5764 17344

5321 18788

5317 18802

i 5286 18913

5281 18931

Data ofBaldet [9] ; bands are red-degraded.

(j) Band heads observed together with the B22+->A2n,- system of CO+

X cr /

A cm-1 3674. 6 27206 3

3662. 6 27295 4

3545. 7 28195 1 3534.

1

28288 1

3377. 7 29597 5 3370.

3

29662 7

3254. 5 30718 4 3247.

5

30784 5

3204. 8 31194 0

3199. 6 31245 0

Data from Johnson [1181.

57
Table 36. Rotational constants for the state

Isotope V B„ D,

(10-8)

C12016 0 1. 922521 6. 1193

1 1. 905014 6. 1184

2 1. 887513 6. 1174

3 1. 870010 6. 1165

4 1. 852513 6. 1155

5 1. 83514

6 1. 81766

7 1. 80018

8 1. 7829

9 1. 7829

10 1. 7475

11 1. 7296

12 1. 7130

13 1. 6957

14 1. 6778

15 1. 6599

16 1. 6434

17 1. 6256

18 1. 6090

19 1. 5910

20 1. 5732

21 1. 5561 22 1. 5390

23 (1. 5220) 24 1.5048

C 130 0 1. 8380

1 1. 8216

C120 18 0 1.8319

1 1.8156

(a) 0=0 through 4, data from Rank et al. [198, 196] and Wiggins [273], Ho~5.8X10~12 cm-1 [198, 196], D values obtained from Dunham constants. Do (exptl.) =6.117X10-8. Uncertainty in Bo is ±0.0000035 cm-1

. (b) 0=5 through 7, data from Goldberg and M011er [85], (c) 0=8 through 24, data from Schmid and Gero. [228], (d) 0=23, B (calc).

(e) Data for 0=0 through 7 derived from vibration-rotation spectra; data

for 0>8 derived from A-X system.

(f) C 13 0 16 from Plyler, Blaine, and Tidwell [193], (g) C 12 0 18 from Mills and Thompson [162],

Table 37. Rotational constants for the A1 !! state

Isotope V B,

C120l« 0 1. 6001

1 1. 5775

2 1. 5561 3 1. 5329

4 1. 5089

5 1. 4861

6 a 1.4616

7 1. 4384

8 1.4138

9 1. 3900

10 1. 3651

11 1. 3421

12 1.3167

13 1. 2915

Data from Schmid and Gero [228], These values obtained fromF(J+§)

Work currently in progress will provide more accurate values in the neai future [238a],

a Data from Onaka [182],

CI3Q16 1 1. 509

2 1. 489

3 1.468

4 1. 446

5 1. 424

Data from McCulloh and Glockler [157b].

Table 38. Rotational constants for the B1 2+ state

Isotope V B 1 D„

GO-®)

Ci2 0i8 0 1. 9475 ~6.1

1 1.921

2 » (1.893)

Data from Schmid and Gero [224].

a Calculated; The identification of the 0=2 level is uncertain [25ft].

C13 Oie 0 1.863 5.4

1 1.837

Data from Douglas and Miller [56]. -

Table 39. Rotational constants for the C1 2+ state

V B, D,

(10-»)

0 »1. 9436 b~5.7

1

a 1.924

» Data from ref. [276].

b Data from ref. [224],

58
Table 40. Rotational constants for the E'n state Table 44. Rotational constants for the c

3 2+ state

Isotope V B, D,

(10-8)

C1201 9 0 1. 9644 6. 50 C13QI8 o 0 1.8773 5. 87

Data from Tilford, Vanderslice, and Wilkinson [257],

° Too =92929.62 cm->.

Table 41. Rotational constants for the a' 3 2+ state

V B„

2 1.2995

3 1. 2823

4 1. 2658

5 1.2478

6 1. 2307

7 1. 2140

8 * 1.1950

9 1. 1816

10 1. 1655

11 » (1. 1470)

13 1.1176

16 1. 0692

19 1. 0206 20 1. 0037

23 0. 958

V B,

0 1. 9563

Data from Gero [77].

Table 45. Rotational constants for the d3 A t state

V B o D„

(10-8) A

3 1. 2512 8.2 -16. 17 4 1. 2344 9.0 -16. 63

7 1. 1840 11.6 -16.9

9 1. 1506 10.1 -17.

1

Data from Carroll [40],

Table 46. Rotational constants for the e

32~ state

V B„

2 1. 2399

3 1. 2221

4 1. 2048

6 1. 1720

8 1. 1360

10 1. 1052

Data from Herzberg and Hugo [101] with v' numbering one unit larger than

in that reference [238a].

Data from Herzberg and Hugo [101].

a Data from Gero and Lorinczi [80].

Table 42. Rotational constants for the a

3n state

V B

,

D

(10-8) Y A Ref.

0 1. 6803 6.1 24.7 41.5 32

i 1. 6627 6.4 25.0 41.5 32

2 1. 6433 6.4 25.1 41.2 32

3 1. 6231 6.2 25.3 41.0 32

4 1. 6026 6.3 54, 16

5 1. 5840 6.3 54, 16

6

a (l. 5644) 7 *(1. 5449)

Data from Budo [32], Dieke and Mauchly [54], and Beer [16], a Calculated. A (average) = 41.3.

Table 43. Rotational constants for the b

3 2+ stale

V B,

0 1.965

i 1.923

Data from Stepanov [246], Schmid and Gero [72, 226] list Bo=2.058, Bi=

2.025; but see [246] and footnote 6

3 S+ to table 1.

Table 47. Rotational constants for the Eo’S4' state

V B,

0 1.182

Data from Tschulanovsky [260].

Table 48. Rotational constants for the ‘n state

v B,

0 1. 139

Data from Tschulanovsky [260].

Table 49. Rotational constants for the f

3 2+ slate

v B,

a 0 0.83

? 0.75

Data from Gero [78].

a j)=o is assumed, but uncertain. Stepanov [247] obtained Bo=O.SOO, Bj=0.711. Both sets of values arc uncertain.

794-908—GG 5 59
Table 50. Rotational constants for the X2 2+ state of CO+ Table 52. Rotational constants for the B'2+ state of CO+

V B, D, V B. D,

(10-6) (10-6)

0 1. 96773 (6. 36) 0 1. 78480 7. 89

i 1. 94871 (6.37) i 1. 75460 8. 06

2 1. 92960 (6. 38) 2 1. 72424 8. 27

3 1. 91039 6.39 3 1. 69409 8. 56

4 1. 89107 (6. 40) 4 1. 6636 8.5

5 1. 87178 (6.41)

6 1. 85244 (6.42)

7 1. 8328 (6.43) Data from Rao [202a].

Data from Rao [202a]. All D , values are estimated, except for »=3.

Table 51. Rotational constants for the A2 !!; state of CO+

V B,

0 1. 57971

l 1. 56022

2 1. 54070

3 1. 52152 4 1. 50203

5 »(1. 48259) 6 1. 46319

7 1. 44375

8 1. 42409

9 1. 40509

10 “(1. 38549)

11 1. 36515

Table 53. Doublet splitting constants for states of CO4

B-X transition

V y

v’-v" W~y"\ (XJ2+) (B22+)

0-1 0. 0093 0 0. 0192

0-2 .0081 l 0. 0285 0-3 .0105 2 .0273

1-2 .0098 3 .0297

1-3 .0084

1-4 .0100

1-5 .0093

2-4 .0090

2-5 .0090

2-6 .0088 3-5 .0079

Data from Rao [202b], D is estimated as ~6.60X10~6

; A =—117.5.

» Calculated. Data on \y’-y"\ from Rao [202a]. Data on y from Rao and Sarma [205].

Table 54. Perturbations of the electronic states of CO and CO+

(a) A'n state

V Max. pert.

(I)

Perturbing termPerturber B,Ref. Comments

0 ~1

8,10,17

9, 12, 16 25

27, 31,34-5 28-9 >30

in (or iA)

3n

e

3 2-, w=l

cm-1 >1.6 44,71

268-9 b 216,44,225,262

50

44. 216 268.216

44,71

See fig. 1 of ref. [44] a. Reality of perturbation disputed [140].

Extra lines J= 11 to 14; B-A, 0-0 band [216].° Q branch line magnetically sensitive. Schmid and Gero [225] called pertuber 3 n at 65002 cm-i, B , ~1.37. Not singlet [268]. Only Q branch perturbed.1.247-1.254

d3A>, v=4

3 n or 3A<

3n

* Both A-components are affected; >A perturber is a possibility. The reported perturbation is large at J~li

b Extra lines [269] for B-A, o-o band at P(8), P(17), Q(8), Q(10), Q(17).

• Extra lines P, R(9), P, R(16), Q (11), (12) ,(13), (14) [216,44]. ~1 in 225, 71,216 ~1 3 n (or 3 A) 216 8 32 1.155 262, 269

23-4, 26, 29 o' 3 2+, v=9 1.15-1.18 216, 44, 43 262 25-6 b 12- 1.50 262, 44

225, 74

26 12+ 43, 209 26 32 44

28 44 29 b 43

34-5 I>2- 1.46 225, 43 >35 o 3 n 216

44 c

32~ 74

a R-X=regular-extra.

t Extra lines R(26), Q (29), B-A [43,44]; P (26), Q(29), A-X [262].

All branches crossed at the same J. Perturber not 2. Q branch, A-X band. Perturber probably a'3 2+. Perturbing term estimated at 66499 cm-1

; a'3 2+

, v=9 is at 66575 cm-'.

Ref. [43] estimates perturber B . to be >1.59.

[44] lists this perturbation, Gero [74] identified the perturber. The reality of this perturbation is not established. It is overlapped by a 32+ perturbation.

[262] believes this to be a 3 2 perturbation with B , ^—1.155. Q branch; see also ref. [52], P, R branch; extra line R-Xa =5.63 cm-i. P branch. Q branch; extra line, R-X=—4.07 cm-1

. Q branch; A-X. See also [262, 44, 52, 234b], P, R branches.

60
Table 54. Perturbations of the electronic stales of CO and CO+—Continued

V Max. pert.

(J)

Perturbing termPerturber B.Ref. Comments

cm~i

2 7 FZ- 73 Q branch; line doubled; no further details given. See also [52]). 19 262 P branch shows trace of a perturbation.

25, 28-9, 33, e

3 Z

-

, 0=4 1.22 216, 44, 262, Perburber estimated at 67953 cm-1 (far from the experimental value [101]). 225

35 216

Extra lines: P, R(25) [216] P, R(33) [216] [In B-A bands.

P(25, 26) [262] >

3 27-8,31,34 a' 3Z+, 0=12 1.14 216,44,262,225 Q, P, Q branches crossed by 3 Z sublevels J=N+1, N, N—1. 29 3Z 1.120 262 P branch.

38 12- 44, 262 Q branch. Schmid and Gero [225] refer to this as the ‘Z perturbation of Coster and Brons. See also [234b, 52], 40 12- 52 50 €32- 74

Extra lines: Q (27, 28) in A-X band

[262].

4 0 32+ 73, 5, 71, 225 P, R, branches.

18 5 P branch; very small perturbation (may not be real). 20 156 McCay refers to a marked decrease in intensity of lines in B-A, 0-4 near

Q(20). 23 FZ- 73, 225 C-A, 0-4; Q branch only. See also [52]. 27 5 Intensity drop; see also [87]. 31 44 B-A, 0-4; reality disputed by [5]. 34, 37, 40 €

3Z-, 0=7 1.17 44,73 Perturber 70878 cm-1 above X. Coster and Brons [44] give 70572 cm-1 which

is in error.

44, 46, 49 a' 32+ 73, 229 50 3n 73

5 30, 33, 35 a' 3Z+ 73, 71 A-X, Q branch. 3Z+ and 3 n cross A'n close to one another, largely overlap. See also [229]. 36 3n 73 A-X, R(35), Q(36), P(37). Perturber may be d3A, 0=14. See Ref. [81]. 44 FZ- 1.17 73 A-X, Q branch. See ref. [52], 50-1, 53, 56 €

3 Z

-

, 0=8 1.13 73 A-X, R(50), P(52) begins a 3Z~ perturbation. See [234b, 229].

6 0 n or A >1.46 182 A-X.

Near head 73 A-X; 3rT, 32 overlap; destroyed order of lines below .T = lfi. 6-8 d3A, 0=12 182 A-X, P, R (7, 8); Q(7, 8).

11, 14, 16 a' 3Z+, 0=17 182 A-X, Q, P, Q; similar perturbation found at 0=0 by Coster and Brons [44] 14 3Ai 182 A-X, Q branch (perturbing state originally identified as 3 U).

29 3 z- 209, 73 30 FZ- 1.11 73, 52

41, 44, 47 e

3 Z- 1.12 229 e

3 Z~, —73777 cm-1

. 45, 47, 50 a' 3 Z+ 1.07 73, 229

52 3 n(?) 73 Q branch; probably the beginning of a 3 n perturbation; other branches not

followed to such high Jvalues, so identification of perturbation is uncertain.

182 Extra lines A-X P Q R

J f 7 7

1 11

1 13 13

l 16

7 26, 29, 32 €

3 Z* 1.14 209, 73 A-X, 7-1. 27 209 A-X, Q branch.

33, 36, 38 a' 3Z+ 1.06 73, 229 39 3 n 73 48 74, 87 Intensity drop; possible perturbation.

8 16, 18, 21 a' 3 Z+ 73, 229 A-X.

27 3n 73 A-X.

34 II z- 0.93 73, 52 A-X.

37 74, 87 Intensity drop; possible perturbation.

9 13 iiz- 0.86 73, 74, 52 Extra line Q (13). 22 74, 87 Intensity breakoff.

28 74

37 32+ 74

61
Table 54. Perturbations of the electronic states of CO and CO+—Continued

V Max. pert. Perturbing Perturber Ref. Comments

(J) term B,

cm-1 10 16, 18, 21 e

3 s- 73 A-X, P(17), Q(18); overlapped by 32+. See [31, 229].

19, 21, 23 a' 32+ 229

32 m 73 A-X. n 16 3 n, '2- 0.62 74, 234b A-X.

12 22, 24, 27 a' 32+ 74, 229 A-X.

13 16 3 II (?) 74, 87 A-X, analysis till J=15, probably 3 n perturbation in all branches at the same J.

(b) E1 !! state

0 31 12+ 257

(c) a3 U state

6 8

. 13-14

| a3 n, V=12 82,81 d—a, 6—0.

14-15 1

(e) /32+ state

0 0 32+ 78 The v numbering is uncertain for the / state N= 13 6

3 2+, t)=0 78

Higher term low J 32+ 78 N =13 632+, v=\ 78

(f) 632+ state

62
Table 54. Perturbations of the electronic states of CO and CO+—Continued

V Max. pert.

(J)

Perturbing termPerturber B.Ref. Comments

(g) A 2n,state of CO+

5 14.5 22.5 X22+, » = 14 X22+, 0=14

cm,-1 45

45

2 IIi^ component perturbed by 2, </=N— i.

2n^ (other A-component) perturbed by 2, «/=N+J. Successive extra lines in both Qi and Q2 branches. 2U3/2 level is unperturbed.

10 X22+, 0=18 35 Numerous levels perturbed (J=3$ to 21J).

Table 55. Observed predissociations in Cl2016 and C13 016 a

Molecule Term V

J for last strong lineJ for first weak lineRotational energy Energy

above X,

0 = 0 , J=0

Ref.

C I2 0 16 B>2+ 0 37 2738.

2

89655. 9 38 2886. 2 89803. 9 56, 43.

1 17 537.8 89587. 6

18 657.0 89656.

8

56, 224, 74.

632+ 0 55 6052.

2

89884.

7

56 6273.

3

90104.

8

74, 72, 226, 75, 30.

1 42 3472. 9 89488

43 3638.3 89653 74.

C>2+ 0 28 1577.

1

93497.

8

29 1689. 7 93610. 4 74,224b 221.

C32+ 0 ~ 27 (1479. 0) (93555. 1) 77, 221.

C13018 B>2+ 0 39 2893.

1

89808.

4

56 (Using observed ZPE from ref. 157b). 40 3040.

8

89956.

1

1 19 697.7 89650.

3

20 771.0 89723.

6

» Hagstrum [87] has summarized the predissociations using slightly different data.

63
Table 56. Vibration-rotation bands of CO in the infrared

region

Isotope

Origin <ro Band Ref.

Obs. Calc. b

C 120 79

err 2116. 80

-i 2-1 193

2143. 274 0. 2731 1-0 192, 193

3996. 88 .9466 7-5 85

4049. 24 .2958 6-4 85

4101. 73 .7820 5-3 85

4154. 404 .4056 4-2 273

4207. 168 .1664 3-1 273

4260. 064 .0646 2-0 a 197

6350. 436 .4404 3-0 197

8414. 458 .4702 4-0 102

C13018 2096. 071 1-0 193 C12018 2092. 12 1-0 162

» Absolute accuracy claimed is 1 part m 5X108

] „ . .. . . . . ,

. . [measurement

Relative accuracy claimed is 1 part in 107

] Calculated line frequencies accurate to 1 part in 109 Similar accuracies claimed for 1-0 band [196],

•> Calculated origins from Wiggins [273]; some data previously given by

Rank et al., [198],

Table 57. Dipole moments for states of CO and CO+

Molecule State n (Debye)

CO X'2 ^ 0. 114±0. 005 Ain . 03±0. 08 B‘2 . 15±0. 15

a8 H b 1. 38

CO+ X22 . 1±0.

1

A2n . 1±0.

1

» This is the value of Burrus [36] to which has been added a polarizability correction of 0.002D [163] (1D = 10-I8 esu).

b A preliminary value determined from the radio frequency spectrum

of the a3 n state [67(a)]. Data from [134],

Table 58. Rotational frequencies, rotational constants, and magnetic moments of carbon monoxide

Isotope Frequency v Transition Wave

length B«° B„d w(=ff) a

MHz mm MHz MHz Nuclear magnetons

C12019 691472. 60±0. 60 6<—

5

0. 43

576267. 75±0. 10 5<—

4

0.52

401040. 68±0. 06 4<-3 0. 65

345795. 900±0. 090 3<—

2

0. 87

230537. 974±0. 030 2<—

L

1. 30

115271. 204±0. 005 l<-0 2.60 6 57898. 462 57907. 863 -0. 26910 C120 U b 112359. 276±0. 060 l<-0 56432. 560 56441. 491 -. 26227 C130 18 110201. 370±0. 008 l«-0 65346. 453 55355. 038 -.25704 . C120 18 109782. 182±0. 008 l<-0 55135. 337 55143. 861 -.25622 C140 1® 105871. 110±0. 004 l«-0 53166. 929 53174. 841 b -. 24664 C13Q I 8 104711. 416±0. 008 1H) 52583. 285 52591. 033 b -. 24418

Ref.

122

86

> 215,47

s The error of ±0.0005 MHz to these values is the absolute error; therelative

errors are about three times smaller.

b Calculated.

» Uncorrected values derived from frequency measurement with values of a«=525.03 MHz, -y ,,=0.0887 MHz, D«=0.18347 MHz [17]. These B« values

differ slightly from those given in ref. [215] primarily because of the different value of a,, which still introduces an uncertainty in the B, values of about

0.2 MHz.

d Corrected for nonspherical distribution of the electrons, wobble stretching, and the Dunham corrections [215, 47],

• Bo=57635.970±0.003 MHz; D0 =O.1839O±O.OOO14 MHz [122, 86]. This

value of Do is not compatible with the preferred value of 0.18345 MHz de- rived from IR data [198, 196],

64
Table

60.

(a)

Franck-Condon

factors

for

the A1- X£

Fourth

Positive

system

to

£>i—I

c/} i—1 i—I o&o

•HSo

Ch

$3

<D r*

-p

ctf -p

ctf ft

go

©> go ^ 3

tRolOHP

PQ

<1

a3

•3

033

o<3

ca

t-©a

>> W

H -H -H

CO 'O o

eo co eo

<N <N s * g -H 8 o 2 O o 3 -H

-H +§ SWo?n I s u || a £ l1 H Cry

O

N

p; ca §a ^

If9 3

65
Table 61. Franck-Condon factors, band strengths, r-centroids, and for the B1 S+— A1 !! Angstrom system

\V" V \

\

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0 0. 08898 0. 18159 0. 21056 0. 18339 0. 13399 0. 08706 0. 06211 0. 20941 0. 01591 0. 00835 0. 00429 0. 00217 0. 00109 0. 00055

0. 088 .171 .154 .139 .110 .091 1.177 1. 158 1.139 1.122 1.106 1.091

6.8 10.0 6.7 4.5 2.6 1.5

1 0. 25053 . 17569 . 03039 . 00420 . 05214 . 09553 . 10665 . 09311 . 07008 . 04781 . 03046 . 01849 . 01085

0. 402 .202 .028 .002 .034 .070 .093 1.205 1.185 1.166 1.148 1.131 1.115 1. 100

4.4 1.7 0 0 0 0.2 0.2

q Ref. [183] (also includes q for w'>2). r-centroid ref. [211]. p Ref. [211]; p and q are made equal for 0-0; I m for the strongest band Ico ref. [211]. in v'= 0 progression is normalized to 10.0.

Table 62. Franck-Condon factors for the 0*2+ —AJ n

Herzberg system

\ v"

v' \\

0 1 2

0 0. 072 0. 165 0. 214

1 .211 .192 .031

2 .293 .034

Data from Leskov (ref. [150]). Table 63. Franck-Condon factors, band strength, r-centroids, and Ia> for the b3 2+ — a

3n Third Positive system

X\ V" \

' \

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0 0. 05810 0. 13468 0. 17897 0. 17905 0. 14996 0.11112 0. 07531 0. 04771 0. 02869 0. 01656 0. 00925 0. 00503 0. 00268 0. 00140

0.054 0.082 0. 066 0.035 0.013 0. 002

1.149 1.131 1.115 1.100 1.086 1.072 8.0 10.0 6.6 2.8 0.8 0.1

1 0. 21702 . 19811 . 06809 . 00213 . 01660 . 06808 . 08657 . 09191 . 08060 .06238 . 04421 . 02935 . 01853

0. 342 0.225 0. 054 0. 001 0. 003 0. 006 0. 003

1.173 1.154 1.136 1.120 1.105 1.091 1.077 64.0 35.0 6.9 0.1 0.3 0.4 0.2

2 0. 32971 0. 02800 . 03677 . 10572 . 07610 . 01909 . 00015 . 01803 . 04558 .06352 . 06708 . 06000

q Ref. [183], loo Ref. [211]. loo for the strongest band in the t>'=0 progression is normal- p Ref. [211]. p and q are made «equal for the 0-0 band. ized to 10.0. r-centroid ref. [211], Table 64. Franck-Condon factors for the a' 32+ — a

3n

Asundi system

v

f v"

0 1 2

o 0. 037 0. 143 0.243

i 103 . 19s .09?

2 .162 ,109 . OOo 3 ,18i .019 . 05o

4 . I65 .003 .059

5 .129 .039 .06? 6 . 09i . 08i .024

V

' l?"

0 1 2

7 0. 059 0.102 0. OOl 8 ,03 6 .099 • 00( 9 . 02i .O82 .023 10 .019 .O64 . 04i

11 .012 . 05o .052 12 .00? .03s .056

Data from Jarmain, Fraser, and Nicholls [114].

66
Table

65.

Franck-Condon

factors

for

the

a^II- XE

Cameron

system

VO VO t- VO V) VO VO k k S 3 S-'Sj 5 & s s

CM CM CM "O »- illiXllh

cvi »a (vj rn *•

r— vo co t— co t—

m o Sisniu S$SSEIPSR

J>

X

A vt in vf KS 8 ? p !r E Jr 8 s s 'O'*-’- <m co t— v> m

fj tr \o ** Ov CM ^

ap M3 irv cmO

A vi

m iK 4 iKX ^ »- vo ro in m o\ »- co

*-

O CO CD Ov

Ov iS t— vo

O CD

O *-

AAO

O

m

m it— 17* t— 0. 1cm 1t— £cm $ov voT

vfmcOK't-co'O'q Ov cm *- O Ov 'T CM ‘vT

illll'Sl I SSSo, Ov CM VO V-VORS3? Ov vo O

VJ^ ffl VO vf i n j

in

r ovr nnnx Tt rM T- V- in W ov mQ VO

-vf VO

CM

O

f- OV

r- CO

VO

O^ a£££|Za.a £( f\J O O Ov

rO I— I— VO

O OV

*- cp vp •** rO C\J 1 MJ

<Jv -3—- t- 4 ik r- <nj(!> - — rM m MIt- » a '& & £ & : nrsrJr <£ :

»“ »- CM -Vj 7 8 £R 1 1 X 4 l

frr »

CM CM co CO 2irv 2X1 ir> ov »- m r vo O'

CM t— CM CO

•V3" CM •'t T 1 T 7 833S ® a x

i&

A

A

SC S! 5 ICO A /vo2 X ll A 3 3 H? 3 £ l ill lk a|X| s 2 2 w- En 8 £ CM OvlrfcOVO'-|»- CO

cm *- in .n .»• * 4 cm a Z| 2 2 £

s,® » |1« 2 & s

CO I CM I rZ t-’ ‘ cO *“ CM Ov 2

"/' ? 1 $ I

71 1 Ill'S. 31 1 1

S3

g SIC £ s> $ ml O irJ h in r .CM

Cjll r- *- OV <M r/ *- 4|X g J l

ii

:Z- a a a

<1 2 X vo m o O CM VO o 00

«- vo CM 83?

CM t- CM

to1—I <—1—l oco

•H§£

ctf -P«

794-908—00

Data

from

Nicholls

[lVS].
Table 68. Franck-Condon factors, r-centroids and I for

the d3A —a

3!! Triplet system

\

\v"

\

0 1 2 3

1 0. 007 0. 043 0.120 0.201 1.298 1.321 1.346 1.371

1 3.4 5.1 4.0

2 0. 031 0.114 0.162 0.091 1.282 1.305 1.328 1.351 5.8 14.9 10.2 3.0

3 0. 068 0.145 0. 074 0.000 1.267 1.289 1.311 17.0 22.8 6.9

4 0. 107 0.113 0. 004 0. 057

1.252 1.274 1.286 1.323

35.1 23.7 0.5 4.4

5 0. 133 0.051 0. 018 0. 079 1.238 1.259 1.287 1.305

56.3 14.3 3.3 8.7

6 0.141 0. 008 0. 061 0.030

1.225 1.243 1.269 1.289

75.3 3.4 14.9 4.7

7 0. 132 0. 002 0. 073 0. 000

1.212 1.241 1.254 87.7 0.8 22.7

8 0.113 0. 022 0. 045 0.020

1.200 1.220 1.252 1.267

90.2 130 18.4 5.2

9 0.086 0. 055 0. 017 0.043

1.186 1.211 1.238 1.240 83.2 38.4 8.4 14.6

q Ref. [240, 2391. r-centroids Ref. [240]. I co ref. [239]. The quantum number v' listed above are one unit higher than that used in

refs. [239, 240]. The tabulated quantities are therefore somewhat uncertain.

68
Table

69*

(a)

Franck-Condon

factors,

r-centroids,

and

wavelengths

for

the A

II.- X£

Comet

Tail

sytem

of

CO • • •

001 OI rf1 CO1 CM1 >H1 rHI CO1 Cl1 CO1 I CO 1 CO 1 1 05 1 to 1 rf 1 to 1 rf 1 00 1 © 1 1 O 05 Tf O CM h- o © -f © O © © © CO to © to © GO

©

—< CO 00 05 CO rf CO rH C5 <£> ’-H

© rH rf

©

© t-

© rf >H (fl oo co rf © O to CO to CM rf rH Tf © CO CO CO rf CO GO CO

rH r-i CO r~i CM rH rf rH rf rH >H rH rH rH CO rH 00H Tf rH M-h • • •

hr1 ©1 CO1 CM| >H| I CO1 | CO1 Cl1 CO1 CM 1 1 05 1 00 1 CM 1 © 1 © 1 C5 _ 1 rf 1 Cl 1 to © —1

h- 05 CO CMO 00 ^ 00

© rH©© ^ Cl CO rH© CM

05 00 00 CO

—< o •H CO 00 CO 00 rH co 00

O

© rH -f 00 Cl

©

© CM © O to to to rH Tf O rf tO rf CO 05 co CO rf CO CO CO H rf i rH rH CM rH >H rH rH rH GO rH rH © rH © rH © rH • • • •

CO1 l CO1 CM1 >H| CM| CMI Cl1 CMI CO1 | H 1 o 1 o , 1 1 CO tO 1 rf _ 1 © 1 Cl 1 CM GX? CO rH 00 rf CO o o o 05 CO CM 00 CO ^ rf CO CO CO rH Tf Ci

© -H CO CO 05 CM CO h- co © i-- rH © © CO rf r-1 © © 00

rf© to rf CM rf CO rf Co rf co

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69
Table 69. Continued—(b) Smoothed hand strengths and

I oo for the A2 n~ X2 S+ Comet Tail system of C0+

\\ v" V'\\

0 1 2 3

0 0. 07i 0. 21 9 0. 25o 1.6 3.1 2.2

1 0.18s 0. 312 0.10s 5.6 6.2 1.3 2 0. 25s 0.162 0. 006 0. 13i 10.0 4.3 — 1.2

3 0.23s 0. 02i .124 0.103 11.9 .7 2.9 1.6

4 0.16s .009 0.16s 10.6 .4 5.3

5 0. 09s .054 0. 073 7.4 3.0 2.9 Order of entry: P V

r I ro =p r't"/X4 r'p"

a j),'," and qv'v" are made equal for the (0,2) band.

b Ia, for the strongest band in v'=2 progression is normalized to 10.0. Data from Eobinson and Nicholls [212], See also Nicholls [177] who lists absolute band strengths.

70
Table

70.

Franck-Condon

factors,

r-centroids,

and

wavelengths

for

the B

v;

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X^x

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Negative

system

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p. co • CD Cd i-H -H 00 ^ to CO o CD to CM i—i 05 M T— © CD O pH CO rt< rt< o 00 to Cd P 1—l O t-h CM Oo Cd CD CO Cd pH CO o T-H • • CM GO r-H t-H H ©0 i—( Cd .-I CO r-H pH rH T-H T-H ip 00 e • o ©

K

r-H1 >H|t-h1 CM to1 to1 I r-i 051t-h1 1 cr 1 co CD 1 ^ *tf 1 CD 1> | 03 oo 1 00 1 05 CD to 1 CO 1 03 00 • co • o to • Cd ph • CM 03 CO rtf C3 t , ph o co 03 ID I" 03 p< CO r-H ,-H rtf 1—t o 00 rH CD

t-h CM to o ©0 Cd

O co co 03 CO P< t-h o CD £r CD r-H to C5

a • • 05 * * b- • . pH • . CO TtlHCO i-i CO t-H t-H CO t-H rH CO Cd t-h t-h Cd CD t-H O o t-H Cd 00 PH ID CO Ip 00 03 © w

i-H h3

72
Table 72. Franck-Condon factors for ionizing transitions

(a) XJ2+(C0+)«-Xiz+(C0) (v"=0)

o' q 2?

0 0. 96355 0. 96355

1 . 03634 . 99989 2 . 00011 1. 00000 3 .00000 1. 00000

4 . 00000 1. 00000

6 . 00000 1.00000

6 .00000 1. 00000

7 . 00000 1. 00000

8 . 00000 1.00000

9 . 00000 1. 00000

10 . 00000 1. 00000

(b) A2 n,(co+)<-x*z+(co)(»"=o)

3 S3

0 0. 07937 0. 07937

1 . 17618 . 25555

2 . 21517 . 47072

3 . 19212 . 66284

4 . 14062 . 80346

5 . 08979 . 89320 6 . 05187 . 94507

7 . 02786 . 97293

8 . 01416 . 98709

9 . 00690 .99399

10 . 00326 . 99725

(c) B2Z+ (CO+)‘—X>Z+ (CO)(»"=0)

3 23

0 0. 68853 0. 68853

1 . 24825 .93678

2 . 05248 . 98926

3 . 00895 . 99821

4 . 00146 . 99967

5 . 00026 . 99993 6 . 00005 . 99998

7 . 00001 . 99999

8 . 00000 . 99999

9 . 00000 . 99999

10 .00000 . 99999

Data from Wacks [264]. Halmann and Laulicht [88a] have calculated q for isotopes C 12 0 IS

, C I3 0 16, and C |2 0 18

.

73
Table 73. (a) Lifetimes, Einstein coefficients, and oscillator strengths

Molecule Transition Band Radiative lifetime t A,' A v" Absorption /-value Ref.

m« 10«S-' 10«s-i CO Ain-Xi2+ ( a

) 0.24 142 0-0 11.2(±0.5)X10-3 9.0 102a

1-0 10.0(±0.5)X10-3 10.0 102a

2-0 10.0(±0.5)X10-3 10.0 102a B 1 2+ —

X

1 2+

( a) 0.034 142 0-0 17X10-3 0.012 102b C>2+ —X'2+ ( a

) >0.28 142 632+ -asn ( b

) 8.6(±0.9)X10-2 8.9(±1.5)X10-3 237a CO+ A2 n,—

X

22+e 1-0 2.61±0.20

1-1 2.95±0.22

2-0 2.48±0.21

2-1 2.74+0.21

3-0 2.36+0.15

19

4-0 2.22+0.13

5-0 2.11±0.13 Average 2.6 2.2(±0.5)X10-3 B22+—

X

22+ 0-0 11.4 8.2X10-3

0-1 8.0 6.4X10-3

0-2 2. 7 2.4X10-3

0-3 0. 45 0.4X10-3

(z/ = 0 Av.) 39.5 (±3) X10-3 22.8

1-0 8. 2 5.5X10-3

1-1 1. 8 1.3X10-3 143

1-2 7. 0 5.7X10-3

1-3 4.3 3.9X10-3

1-4 1. 1 1.1X10-3

( v'=l Av.) 39.5(±3)X10-3 22.8

( v'=2 Av.) 38.8(±4)X10-3 23.2

( c) 39.5(±8)X10-3 18(±3.6)X10-3

(o) 1.01(±0.05)X10-i 7 9 (±0.7) X10-3 237a

( d) 2.8 251

a Integrated/-value for the system from inelastic electron scattering. Table

73 (c) lists /-values for bands of this system.

b t and/ for v'=0.

» Average for the B-X transition. The discrepancy between the two

values is as yet unexplained.

d Continuum, 876-374 A.

e Decay of emission from each band observed. Lifetimes of upper

vibrational levels measured.

(b) Einstein coefficients > absolute band

strengths, and band oscillator strengths

for the A

2

TL - X

2^" Comet Tail system of C0+

v"

v

r 0 1 2 3 4.37+4 9.47+4 7.63+4

0 1.01-2 3.11-2 3.66-2

1.58-4 4.30-4 4.45 —4 1.42+5 1 . 75+5 3.90+4

l 2.65-2 4.50-2 1.21-2 4.44-4 6.74-4 1.70-4

2.37+4 1.13+5 4.33+4-

2 3.65-2 2.33-2 1.76-2

6.50-4 3.75 —4 2.26-4

2.66+5 1.71+4 7.84+4 4.83+4-

3 3.51-2 2.88-3 1.78-2 1.52-2

6.64-4 4.98-5 2.78-4 2.13-4

2.24+5 9.19+3 1 .33+5

4 2.14-2 1.29-2 2.42-2

4.83-4 2.36-4 4.07-4

1.48+5 6.51+4 6.84+4

5 1.36-2 7.67-2 1.03-2

2.88-4 1.49-4 .1.85-4

LEGEND : Av' V

I 1 (sec 1

); Pv

,V (a

Q 2e2 )» fv

' v

'»

*

Data from Nicholls [177

]

Table 73—Continued

(c) Absolute f-values for the A1 !! —

X

J 2+ Fourth Positive system

/v'v" (X 10-3)

»'\

0 1 2 3 4 5 6 7 8 9 2

0 9.0 20.0 21.2 14.

1

6.7 2.4 73.5

1 20.2

22.6

14. 0 0.3 6. 5 15. 8 14.7 8.2 3.3 83.0

2 1.2 8.3 10.3 0.4 4.8 13.2 12.9 7.4 3.0 84.1

Data from Hesser and Dressier [102a],

74
Table 74. Potential energy of the electronic states of CO and CO+ * Table 74. Potential energy of the electronic states of CO and CO+—Continued

Potential energy of the X'2+ state of CO (r.— 1.128322 A)° ° Potential energy of the a' 3 Z + state of CO (T, =55822.92 cm_l =6.9210 eV, r,—

1.3519A)

V V V T m in Tin ax V V V T.+V T.+V Tmin T m ax

0 cm-11081. 590 eV

0. 1341 A1.083 A1.179 cm-1 eV cm- 1 eV A A

1 3224. 864 .3998 1.053 1.220 0 612. 581 0. 0759 56435. 50 6. 9969 1.290 1.423

2 5341. 654 .6623 1.034 1.250 i 1821. 44 .2258 57644. 36 7. 1468 1.257 1.478 3 7432. 026 .9214 1.020 1.276 2 3008. 83 .3730 58831. 75 7. 2940 1.232 1.520 4 9496. 048 1. 1773 1. 008 1.300 3 4175. 16 .5176 59998. 08 7. 4386 1. 214 1.557

5 11533. 76 1. 4300 0. 997 1.322 4 5321. 31 .6597 61144. 23 7. 5807 1. 198 1. 591

6 13545. 29 1. 6794 .988 1.343 5 6446. 32 .7992 62269. 24 7. 7202 1. 185 1.622

7 15530. 64 1. 9255 .980 1.363 6 7552. 31 .9363 63375. 23 7. 8573 1. 174 1. 653

8 17489.

9

2. 1684 .972 1.383 7 8638. 11 1. 0710 64461. 03 7. 9920 1. 164 1. 682

9 19423. 5 2. 4081 .965 1. 402 8 9705. 57 1. 2033 65528. 49 8. 1243 1. 155 1. 711

10 21330. 7 2. 6446 .959 1.420 9 10751. 15 1. 3329 66574. 07 8. 2539 1. 147 1.739

11 23212.

4

2. 8779 .953 1.438 10 11779. 26 1. 4604 67602. 18 8. 3814 1. 139 1.766

12 25068. 5 3. 1080 .947 1.456 11 12788. 37 1. 5855 68611. 29 8. 5065 1. 132 1.793

13 26898.

4

3. 3349 .942 1.474 12 13778. 58 1. 7083 69601. 50 8. 6293 1. 126 1. 820

14 28703.

2

3. 5587 .937 1.492 13 14750. 12 1. 8287 70573. 04 8. 7497 1.120 1. 847

15 30482. 7 3. 7793 .932 1.509 14 15703. 24 1. 9469 71526. 16 8. 8679 1.114 1. 874

16 32235.

4

3. 9966 .928 1.526 15 16637. 78 2. 0628 72460. 70 8. 9838 1.108 1. 900

17 33963. 9 4. 2109 .923 1.544 16 17554. 01 2. 1764 73376. 93 9. 0974 1. 103 1.927

18 35666. 8 4. 4220 .919 1.561 17 18451. 41 2. 2876 74274. 33 9. 2086 1.099 1.954

19 37344.

4

4. 6300 .916 1.579 18 19330. 47 2. 3966 75153. 39 9. 3176 1. 094 1. 981 20 38997. 5 4. 8349 .912 1.596 19 20190. 91 2. 5033 76013. 83 9.4243 1.090 2. 009

21 40625. 7 5. 0368 .908 1.614 20 21032. 78 2. 6077 76855. 70 9. 5287 1.086 2. 036 22 42208 5. 2330 .905 1.631 21 21855. 93 2. 7097 77678. 85 9. 6307 1.082 2.064

23 43776 5. 4274 .901 1.649 22 22660. 14 2. 8094 78483. 06 9.7304 1. 079 2. 092

b 24 45307 5. 6172 .898 1.668 23 23443. 67 2. 9066 79266. 59 9. 8276 1.075 2. 121

b 25 46803 5. 8027 .894 1.686

‘Data for the e

3S~ state [138] are not included because of a revision in vibrational quantum numbering [238a]. The newly revised numbering is definitive (sec. 3.10).

° Data for v =0 to 7 from vibration-rotation spectra.

b Extrapolated to highest observed level.

»r»: See footnote X'S-*-, table 1. Data taken from Krupenie and Weissman [138].

Potential energy of the a 3 H state of CO (T e =48687.40 cm-^6.0363 eV, r »—

1.2058 A)

V V V T.+V T.+V T min /max

cm-1 eV cm-1 eV A A

0 868. 16 0. 1076 49555. 56 6. 1440 1. 157 1.263

l 2582. 77 .3202 51270. 17 6. 3565 1. 124 1.310

2 4266. 7 .5290 52954.

1

6. 5653 1. 103 1. 344

3 5921. 2 .7341 54608. 6 6. 7704 1.087 1. 375

4 7546. 8 .9357 56234. 2 6. 9720 1. 074 1.403

5 9143. 3 1. 1336 57830. 7 7. 1699 1. 063 1.429

“ 6 10710 1. 3278 59398 7. 3642 1.052 1.454

> 7 12246 1. 5183 60934 7. 5547 1.043 1.478

» Extrapolated to highest observed level.

Potential energy of the d3 Ai state of CO (T e =61154.06 cm-i=7.5820 eV,

r e = 1.3700 A)

V V V T.+V T.+V Tmin Tmax

cm-1 eV cm-1 eV A A

0 574. 46 0. 0712 61728. 52 7. 6532 1.309 1.440

i 1712 .2123 62866 7. 7942 1.270 1. 498

2 2834 .3513 63988 7. 9333 1.245 1.541

3 3940 .4885 65094 8. 0705 1.226 1.579

4 5029 .6235 66183 8. 2055 1.211 1.613

5 6100 .7563 67254 8. 3383 1.197 1.645

6 7153 .8869 68307 8. 4688 1. 186 1.676

7 8187 1.0151 69341 8. 5970 1. 176 1. 707

8 9202 1. 1409 70356 8. 7228 1. 167 1.736

9 10196 1.2641 71350 8. 8461 1.158 1.765

10 11169 1. 3848 72323 8. 9667 1. 150 1. 794

11 12121 1. 5027 73275 9. 0847 1. 143 1.823

12 13050 1. 6179 74204 9. 1999 1. 136 1.852

13 13956 1. 7303 75110 9. 3123 1. 130 1. 881

14 14839 1.8397 75993 9. 4217 1. 124 1.910

15 15697 1. 9461 76851 9. 5281 1.118 1.940

16 16530 2. 0494 77684 9.6314 1.112 1.970

17 17337 2. 1495 78492 9. 7315 1. 106 2.000

18 18118 2. 2463 79273 9.8283 1. 101 2.032

19 18873 2. 3398 80027 9. 9218 1.095 2.064

20 19599 2. 4299 80753 10. 011S 1.090 2.097

21 20297 2.5164 81451 10. 0084 1. 0S4 2.132

22 20966 2.5993 82120 10. 1813 1.079 2.167

75
Table 74. Potential energy of the electronic states of CO and CO+—Continued

Potential energy of the A! n state of CO (T, =65074.6 cm-1 =8.0680 eV, r,=

1.2352 A)

V V V T.+V T .+V Tmin Tin ax

cm-1 eV cm-1 eV A A

0 753. 49 0. 0934 65828.

1

8. 1614 1. 183 1. 297

i 2242.

3

.2780 67316. 9 8. 3460 1.148 1.348

2 3685.

2

.4569 68759. 8 8. 5249 1. 126 1.387

3 5097.

9

.6320 70172.

5

8. 7001 1.110 1. 422

4 6476.

1

.8029 71550. 7 8. 8709 1.096 1.454

5 7818.

2

.9693 72892.

8

9. 0373 1.085 1. 484

6 9125.

0

1. 1313 74199. 6 9. 1993 1. 075 1.514

7 10401. 8 1. 2896 75476.

4

9. 3576 1. 066 1. 542

8 11641.0 1. 4433 76715.

6

9. 5113 1.058 1.571 9 12846.

9

1. 5928 77921. 5 9. 6608 1.051 1.599

10 14018. 8 1. 7381 79093. 4 9. 8061 1.044 1. 627

11 15155.

6

1. 8790 80230.

2

9. 9470 1.038 1.656

12 16262 2. 0162 81336 10. 0841 1.032 1. 685

13 17333 2. 1490 82407 10. 2169 1. 027 1.714

14 18371 2. 2777 83445 10. 3456 1.022 1. 743

15 19366 2. 4010 84440 10. 4690 1. 017 1.773

16 20330 2. 5205 85404 10. 5885 1.013 1.804

17 21257 2. 6355 86331 10. 7034 1. 009 1.837

18 22138 2. 7447 87212 10. 8126 1.005 1.871

a 19 22970 2. 8478 88045 10. 9159 1.001 1.909

a 20 23762 2. 9460 88837 11.0141 0. 996 1.951

» Extrapolated to highest observed level.

Potential energy of the I'Zstate of CO (T, =66185 cm-i= 8.2057 eV, r»=

1.416 A)

V V V T.+V T.+V Train Tmax

cm-1 eV CTO-1 eV A A

0 530 0. 066 66715 8. 271 1.35 1. 48

i 1580 .196 67760 8. 401 1. 29 1.53 2 2600 .324 68790 8. 528 1.25 1.56 3 3610 .448 69790 8. 653 1. 22 1. 59

4 4600 .571 70780 8. 776 1.19 1.61

5 5560 .690 71750 8.896 1. 16 1.64

6 6510 .808 72700 9. 013 1.14 1. 66

7 7450 .924 73630 9. 129 1.12 1.68

8 8360 1.037 74540 9.242 1.09 1.69

9 9250 1.148 75440 9. 353 1.07 1.71

10 10120 1. 257 76310 9. 461 1. 05 1.73

11 10980 1. 363 77160 9. 567 1. 03 1. 75

12 11810 1.467 78000 9. 670 1.01 1. 77

Potential energy of the B12+ state of CO (T ,=86928 cm-1 =10.7774 eV,

r,=1.120 A)a

V V V T.+V T.+V Tmin Tinas

cm~1 eV cm-1 eV A A

0 1072 0. 1329 87998 10. 9101 1.08 1. 17

i 3154 .3910 90080 11. 1682 1.05 1. 22

2 5154 .6390 92080 11.4162 1.03 1.25

a Curve taken from ref. [258] but with different Z.P.E.

Table 74. Potential energy of the electronic states of

CO and CO+—Continued

Potential energy of the X2Z+ state of CO+ (T, =113007 cm-^14.0108 eV,

r,=l.11516 1)

V V V T.+V T.+V Tmin Tin ax

cm-1 eV cm-1 eV A A

0 1103. 33 0. 1368 114110. 33 14. 1475 1.071 1.165

i 3287. 22 0. 4076 116294. 22 14. 4183 1. 041 1.206

2 5440. 80 0. 6746 118447. 80 14. 6853 1. 023 1. 236

3 7564. 01 0. 9378 120571. 01 14. 9486 1.008 1.263 4 9656. 94 1. 1973 122663. 94 15. 2080 0. 996 1.286

5 11719. 47 1. 4530 124726. 47 15. 4637 0. 986 1.309

6 13751. 63 1. 7049 126758. 63 15. 7157 0. 977 1.330

7 15753. 47 1. 9531 128760. 47 15. 9639 0. 968 1.350

8 17724. 95 2. 1976 130731. 95 16. 2083 0. 961 1.370

9 19666. 6 2. 4383 132673.

6

16. 4490 0. 954 1.390

10 21578.

2

2. 6753 134585.

2

16. 6860 0.948 1.409

11 23459. 2 2. 9085 136466.

2

16. 9193 0.943 1.428

12 25310. 0 3. 1380 138317.

0

17. 1487 0. 938 1.447

13 27102.

3

3. 3602 140109.

3

17. 3709 0. 933 1. 466

Potential energy of the A2 II; state of CO-*- (T,= 133740 cm-1 = 16.5813 eV,

r.= 1.24378A)

V V V T ,+V T.+V fmin Tin ax

cm~l eV cm-1 eV A A

0 777. 65 0. 0964 134517. 65 16. 6777 1. 191 1. 304

i 2312. 88 .2868 136052. 88 16. 8680 1. 157 1. 354

2 3820. 74 .4737 137560. 74 17. 0550 1.136 1.391 3 5301. 83 .6573 139041. 83 17. 2386 1.119 1.424

4 6756. 38 .8377 140496. 38 17. 4189 1. 105 1.453

5 8184. 11 1. 0147 141924. 11 17. 5959 1.094 1. 481

6 9585. 20 1. 1884 143325. 20 17. 7697 1.083 1. 508

7 10959. 79 1. 3588 144699. 79 17. 9401 1. 074 1.534

8 12307. 90 1. 5259 146047. 90 18. 1072 1. 066 1.560

9 13629. 46 1. 6898 147369. 46 18. 2711 1. 059 1.585

10 14924. 72 1. 8504 148664. 72 18. 4317 1.052 1.610

11 16193. 82 2. 0077 149933. 82 18. 5890 1. 046 1. 634

Potential energy of the B22+ state of CCH- (T,= 158884 cm-1 =19.6987 eV, r.— 1.16878 A)

V V V T.+V T,+V Tmin Tmax

cm-1 eV cm-1 eV A A

0 860. 15 0. 1066 159744. 15 19. 8053 1. 120 1.227

i 2539. 55 .3149 161423. 55 20. 0135 1. 089 1.277

2 4166. 05 .5165 163050. 05 20. 2152 1.069 1.315 3 5741. 62 .7119 164625. 62 20. 4105 1. 054 1.349

4 7268. 23 .9011 166152. 23 20. 5998 1.042 1. 381

5 8749.

8

1. 0848 167633.

8

20. 7835 1. 032 1. 411 6 10186. 9 1. 2630 169070.

9

20. 9616 1. 023 1. 441

7 11588. 7 1. 4368 170472. 7 21. 1354 1. 015 1. 471 8 12920. 7 1. 6019 171804. 7 21. 3006 1.008 1.500

9 14193.

8

1. 7598 173077.

8

21. 4584 1.001 1.531

a 10 15390.

1

1. 9081 174274.

1

21. 6067 0. 993 1.564

» Extrapolated to highest observed level.

76
VteV)

Figure 1. Potential energy curves for CO and CO+.

r(A)

10 cm' eV

Figure 2. Energy level diagram for CO and CO+ .

77
13. References

The references cited below have been traced from a number of standard sources [99, 187, 213, 117, 69]. Recent

references have been traced through the use of

:

(a) Herzberg, G.', and Howe, L. L., “Bibliography of Spectra of Diatomic Molecules, 1950-1960”, Ottawa.

(b) Mulliken, R. S., “Bibliography on Diatomic Molecules, 1950-1960”, Chicago.

(c) Phillips, J. G., and Davis, S. P., Newsletter, “Analysis of Molecular Spectra”, Berkeley.

These sources have been supplemented by the use of Current Contents and Chemical Abstracts (Vol. 1 to the

present). The literature search terminated in May, 1965.

Most valuable as general references are the books by

Herzberg [99], Johnson [120], and Jevons [117], the latter having recently been republished by University Microfilms.

A review by Birge [23] in 1926 is the most convenient

source for tracing the earliest works on CO spectra, many

of which by now are mainly of historical interest.

[1] Amaldi, E., On the Raman effect of CO, Z. Physik

79, 492-94 (1932).

[2] Anand, B. M., Bands forming Rydberg series and

ionization potential of carbon monoxide, Sci. Cult.

(Calcutta) 8, 278-79 (1942).

[3] Asundi, R. K., A new band system of carbon monoxide, Nature 123, 47-8L (1929).

[4] Asundi, R. K., The third positive carbon and associated bands, Proc. Roy. Soc. (London), Ser. A:

124, 277-96 (1929).

[5] Asundi, R. K., Rotational analysis of the Angstrom

bands at XX 6080 and 6620 A.U., Proc. Indian

Acad. Sci., Sect. A. 3, 554-61 (1936).

[6] Asundi, R. K., A new comet tail band, Current Sci. (India) 9, 503-4L (1940).

[7] Asundi, R. K., New bands in the triplet carbon

system, Proc. Indian Acad. Sci., Sect. A. 3, 491-93

(1940).

[8] Baldet, F., The spectra of the thermionic discharge

in carbon monoxide, Compt. Rend. 178, 1525-27

(1924).

[9] (a) Baldet, F., The spectra of carbon monoxide at very low pressure, and the spectra of comet

tails, Compt. Rend. 180, 271-73 (1925).

(b) Baldet, F., On the third negative group of car- bon and the spectra of comet tails. Extension to the red and structure of the bands,

Compt. Rend. 180, 820-22 (1925).

[10] Baldet, F., The band spectra associated with carbon,

Nature 116, 360 (1925).

[11] Barbier, D., Presence in the night sky spectrum of unidentified new bands, Intern. Conf. (July, 1947)

Gassiot Comm., Roy. Soc. London, 8-12 (1948).

(C.A. 44, 5699c).

[12] Barrow, R. F., Triplet bands of carbon monoxide:

the system e

3 Z

_-a3 n, Nature 189, 4S0-1L (1961).

[13] Barrow, R. F., Gratzer, W. B., and Malherbe, J. F., Intensities of bands in the system 6

32+-a3 n of carbon monoxide, Proc. Phys. Soc. (London)

A69, 574-6 (1956).

[14] Bates, D. R., Relative transition probabilities in band systems of diatomic molecules, Monthly

Notices Roy. Astron. Soc. 112, 614-36 (1952).

[15] Bedard, F. D., Gallagher, J. J., and Johnson, C. XL,

Microwave measurement of D0 for CO, Phys.

Rev. 92, 1440 (1953).

[16] Beer, B. S., Rotational analysis of the 0—>4, 0—>5, 1—»4, and 1—>5 bands of the III. positive system of CO, Z. Physik 107, 73-85 (1937).

[17] Benedict, W. S. (private communication).

[18] Benedict, W. S., Herman, R., Moore, G. E., and

Silverman, S., The strengths, widths, and shapes

of lines in the vibration-rotation bands of CO,

Astrophys. J. 135, 277-97 (1962).

[19] Bennett, R. G., and Dalbv, E. W., Experimental

oscillator strength of the comet-tail system of CO+, J. Chem. Phys. 32, 1111-13 (1960).

[20] Bhagavantam, S., Raman effect in gases: CO and

NO, Phys. Rev. 42, 437L (1932).

[21] Birge, R. T., The band spectra associated with carbon,

Nature 116, 170-1L (1925).

[22] Birge, R. T., The energy levels of the carbon monoxide molecule, Nature 117, 229-30 (1926).

[23] Birge, R. T., The band spectra of carbon monoxide,

Phys. Rev. 28, 1157-81 (1926).

[24] Biskamp, H., Study of the first negative group of CO+, Z. Physik 86, 33-41 (1933).

[25] Blackburn, C. M., Analysis of the “comet tail”

bands, (abstract) Phys. Rev. 25, 888 (1925).

[26] Blackburn, C. M., An application of the quantum

theory of band spectra to the first negative Deslandres group of carbon, Proc. Nat. Acad. Sci. EPS.

11, 28-34 (1925).

[27] Brewer, L., Gilles, P. W., and Jenkins, F. A., The

vapor pressure and heat of sublimation of graphite,

J. Chem. Phys. 16, 797-807 (1948).

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Appendix A. Notation and Terminology

The spectroscopic notation used in this report

is that adopted in Herzberg’s book [99] as modified

by recommendations of the Triple Commission

on Spectroscopy (J. Opt. Soc. Am. 43, 425-30

(1953); 52, 476-7 (1962); 53, 883-5 (1963)). A

number of specific conventions used are itemized

below.

(1) Wavenumber in cm-1

is denoted by cr; v is reserved for frequency in s

-1

.

(2) N is total angular momentum of electrons

and nuclei exclusive of spin (case b, b', d), formerly denoted by Iv.

(3) Rotational angular momentum of the nuclei,

85
formerly denoted by N, is now denoted

by O.

(4) Dissociation energy is written as D° or D e

; rotational constants (for the zero level or equilibrium value, respectively) are denoted as usual by D0 and De

.

(5) A transition is always represented with a

dash, as

2 II— 22 transition. The upper

state is always written first. <— means

absorption; —> means emission, for an

electronic, vibration-rotation, or rotational

(here, microwave) transition.

(6) A perturbation by one state of another is indicated as e.g., (Wn) perturbation, following an early notation of Kovacs.

(Conventions used in some early papers

include or ! A,

(7) A progression of bands is indicated as follows

;

e-g., (a) v" =0 progression

(b) (v

f —0) progression.

(8) Reciprocal dispersion is given in A/mm.

However, following the colloquial use of

many spectroscopists this quantity is re- ferred to as dispersion.

(9) In the tables, wavelengths above 2000 A

are air wavelengths unless otherwise specified; below 2000 A vacuum wavelengths

are listed.

(10) The known band degradation is indicated by

R (red-degraded) or V (violet-degraded)

in the headings of section 3 as well as in

tables 1 and 3 to 35.

(11) Rotational constants in tables 36 to 52 are given in units of cm-1

. (12) Abbreviations used are listed on p. 2 In

addition, zero-point energy is abbreviated

by ZPE.

The following items apply to table 1. (1) Vibrational constants and term values T are assumed to be derived from data on band

origins. (Herzberg [99] denotes these by

the letter Z.) In conformity with Herzberg, H denotes constants derived from

head measurements.

(2) [r e] means r0 ; [B e] means B0 ; [w e] means AGQ)

,

as in Herzberg’s book.

(3) ( ) means uncertain.

(4) T0 is the mean height (in case of multiplets)

above X, v=0, J—0. (5) States which are predissociated have Pr

written in the column for dissociation

products. (For CO all known predissociations are due to 3 P+3P states.)

(6) All numerical data are in units of cm-1 unless

otherwise indicated.

(7) References cited include only those from

which the numerical data have been

extracted. Other pertinent references are

cited in the appropriate sections of this

report.

(8) The tabulated molecular constants have been

taken from the references cited in table 1 but are not necessarily those which best fit the individual vibrational term values or rotational constants where these have been

compiled from various sources.

(9) To avoid confusion of sign conventions

several formulas are fisted below:

Vibrational terms:

G(v)=a}e (v+%)—UeXe (v+%) 2 +CO eye (y V|) 3 +^e2eC' +^)

4

i.e., a negative value of u>eX e from the

table would mean a positive anharmonic term.

Rotational terms:

F,(J)=BJ(J+1)-DJ2 (J+1) 2 +HC J

3 (J+1) 3

where (— D^) is always <(0, and

Ba =Be —a e (v-\-%) +7e(y + !)

2+5 e (y +^) 3 D„=De +/3e (2;+!) [for CO, X1 ^, |3<0]

H0 ~H,.

(10) Footnotes which give supplementary information pertaining to the individual electronic states are indicated at the end of

table 1 and are identified by the electronic

state. Table 1 has been left free of superscripts.

(11) The tabulated ZPE do not include the Dunham correction which would add an amount given by

y

Be . aewe . flfWj LOfXe 00—4 I2BC l44Bl

4~*

(For the ground state this correction is 0.600 cm-1

.)

86
Appendix B. Physical Constants10-12 and Conversion Factors

c=2.997925X 10-10 cm-s"1 h= 6.6256 X10-27 erg-s

N0 =6.02252 X 1023 mole"1

1 eV==8065.73 cm-^23.0609 k-cal-mole- 1 Ma(C120

16) =6.85621

Ma(CO+) =6.85603

m=Ma/N0 : ju(CO) = 1.13843 X10-23 g

n (CO+

) = 1 . 13840 X 1

0

-23 g

w The molecular reduced masses are calculated from the data of Everling

et al.. Relative Nuclidic Masses, Nuclear Phys. 18, 529-69 (1960) which are based on the unified atomic weight scale with C 12=12.

11 The mass aia(CO+) was calculated by assuming 5.49X10-4 a.m.u. for the mass of the electron and assuming that ionization removes an electron from the C atom (1 a,m.u.=l/12 mass of CiJ).

1 2 The universal constants and conversion factors are those recommended

by the NAS-NRC (Phys. Today, pp. 48-9 (Feb. 1964)).

Atomic weights:

C= 12

0= 15.994915

&e (CO)=40.3930X 10 -2

co 2

& e (CO+)=40.3920X 10 -2w

2 VB,

re (CO) =l. 568031

re (CO+) = 1.568052

(co e in cm x

; ke in

dyne-cm _1

)

(Be in cm x

; re in A)

The “Tabelle der Schwingungszahlen” of Kayser

has been superseded by NBS Monograph 3,

“Table of Wavenumbers,” by Coleman, Bozman,

and Meggers (1960) which is based on the 1953

formula for dispersion in standard air of Edlen.

For low resolution work the older tables are adequate.

87
Ao
(cut

here)

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