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NSRDS-NBS 34

NSRD

Ionization Potentials

and Ionization Limits

Derived From the Analyses

of Optical Spectra

u.s.

DEPARTMENT

OF

COMMERCE

National

Bureau

andards

UNITED STATES DEPARTMENT OF COMMERCE • Maurice H. Stans, Secretary

NATIONAL BUREAU OF STANDARDS • Lewis M. Branscomb. Director

Ionization Potentials and

Ionization Limits Derived from

the Analyses of Optical Spectra

Charlotte E. Moore

Office of Standard Reference Data

National Bureau of Standards

Washington, D.C. 20234

NSRDS-NBS 34

Nat. Stand. Ref. Data Ser., Nat. Bur. Stand. (U.S.), 34, 22 pages (Sept. 1970)

CODEN: NSRDA

© 1970 by the Secretary of Commerce on Behalf of the United States Government

Issued September 1970

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C., 20402 (Order by SD Catalog No. C 13.48:34)- Price 75 cents
NATIONAL BUREAU OF STANB/.E'.n*

MAY 1 7 1971

H o i z-£&

&ClO 0

.OS 1\

I? i°

?r

Library of Congress Catalog Card Number: 76-607107
FOREWORD

The National Standard Reference Data System provides effective access to the quantitative

data of physical science, critically evaluated and compiled for convenience, and readily accessible

through a variety of distribution channels. The System was established in 1963 by action of the

President’s Office of Science and Technology and the Federal Council for Science and Technology,

with responsibility to administer it assigned to the National Bureau of Standards.

The System now comprises a complex of data centers and other activities, carried on in

academic institutions and other laboratories both in and out of government. 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. In addition, the centers and projects establish

criteria for evaluation and compilation of data and make recommendations on needed improvements in experimental techniques. They are normally closely associated with active research

in the relevant field. The technical scope of the NSRDS is indicated by the principal categories of data compilation

projects now active or being planned: nuclear properties, atomic and molecular properties, solid state properties, thermodynamic and transport properties, chemical kinetics, and colloid and

surface properties.

The NSRDS receives advice and planning assistance from the National Research Council

of the National Academy of Sciences-National Academy of Engineering. An overall Review Committee considers the program as a whole and makes recommendations on policy, long-term planning,

and international collaboration. Advisory Panels, each concerned with a single technical area, meet regularly to examine major portions of the program, assign relative priorities, and identify

specific key problems in need of further attention. For selected specific topics, the Advisory

Panels sponsor subpanels which make detailed studies of users’ needs, the present state of knowledge, and existing data resources as a basis for recommending one or more data compilation

activities. This assembly of advisory services contributes greatly to the guidance of NSRDS

activities.

The NSRDS-NBS series of publications is intended primarily to include evaluated reference

data and critical reviews of long-term interest to the scientific and technical community.

Lewis M. Branscomb, Director

in
Contents

Page Foreword Ill Introduction 1 Table 1. Ionizational potentials 2

Table 2. Ionization limits and lowest terms 6a-6i

Table 3. Bibliography 6

IV
Ionization Potentials and Ionization Limits Derived from the

Analyses of Optical Spectra

Charlotte E. Moore

A current table of ionization potentials expressed in electron volts and a detailed table giving

the limits from which they have been derived are presented. For each spectrum the ground term is given, with the limit as the ground state. The energy levels of terms of the lowest configuration deter- mined from ground state zero, are also included for selected spectra. The literature references used

for each spectrum are indicated by number and listed in a bibliography with some 200 entries. The latest recommended conversion factor (cm -1 to eV) 0.000123981 corresponding to 1 eV =

8065.73 cm' 1 has been used throughout.

Key words: Atomic spectra, ground terms; ground terms, atomic spectra; ionization limits; ionization

potentials.

The data in the Volumes on “Atomic Energy

Levels" (AEL) [135], [136], [137], include the

ionization limits known for individual spectra. The

latest table of ionization potentials calculated from

these limits was published as Table 34 in Volume

III (1958). Much work has been done since then and

there has been a steady demand for a revision of

this Table.

A fairly comprehensive general bibliography has

recently been published [194] which lists for each

spectrum the literature references on analyses of

atomic spectra dating from the entries in the respective Volume of “AEL” (1949), (1952), (1958), well

into 1968. The present compendium is based largely on the references in this Bibliography, with some,

but probably not all, later material.

The reliability of the data recorded in the literature is often difficult to appraise. In cases where

long series are known in the various spectra, the

ionization potentials are well determined. With

these as key points, good values can be derived by

extrapolation or interpolation along isoelectronic

sequences, or by comparison along the rows in the

Periodic Chart for spectra of similar stages of ionization. Frequently, however, authors give values of

ionization potentials without stating the conversion

factor used and without describing clearly how the

quoted value was obtained.

For this reason, the present paper includes not

only the ionization potentials in eV, but also, the

limits in cm~' from which these have been derived.

Table 1 gives the ionization potentials in eV for

each spectrum.

The conversion factor taken from [195] was used

for Table 1, since it is the value currently recom- mended by the National Academy of SciencesNational Research Council. However, recent meas- urements [200] suggest that this value may be in error by about 30 parts per million. Therefore, it should be understood that all of the significant

figures included in Table 1 may not be meaningful

in an absolute sense. This applies particularly to entries with magnitudes greater than 100 eV.

All limits have been multiplied by the factor

0.000123981 to obtain the entries in Table 1, i.e.,

1 eV = 8065.73 cm' 1

. The factor used in “AEL”

was 0.00012395 and has been superseded. As a re- sult, in the present table there are systematic dif- ferences from the 1958 Table, caused by the change

in the conversion factor, as well as the differences

caused by improved values of the limits.

Italics denote ionization potentials derived from

limits that are bracketed in Table 2. In compiling Table 1 the author has attempted to indicate roughly the various degrees of accuracy of

the limits. Those based on well-established series

deserve the greatest weight. When the ionization

potential is given to three places, it is felt that the

third place is meaningful. The two- and one-place

entries are less well defined, but it is hoped that

they have some significance. The limits of error assigned by the various investigators provide a general criterion, but these are given for comparatively few spectra. Users should, therefore, consult

the limits given in Table 2 and the references in

order to evaluate the data for individual spectra.

Table 2 contains the basic data for each spectrum.

As in Table 1, the successive stages of ionization are indicated at the heading of each column: I, denoting first spectra (neutral atoms); II, second

spectra (singly ionized atoms), etc. The elements

are arranged in order of increasing atomic number,

Z. The ground state is indicated for each spectrum,

together with the ionization limit in cm -1

. In every

case this limit refers to the ground state of the ion

in the next higher stage of ionization. The limits of error are quoted from the original authors. Although

not specifically defined, these afford a general guide

as to the reliability of the limit.

Although all limits are based on data derived

from the analyses of optical spectra, they are determined in various ways, since reliable series are

1
Table I. Ionization potentials

z Element

Spectrum

I II ill IV V VI VII VIII IX X

1 H 13.598

2 He 24.587 54.416

3 Li 5.392 75.638 122.451

4 Be 9.322 18.211 153.893 217.713

5 B 8.298 25.154 37.930 259.368 340.217

6 C 11.260 24.383 47.887 64.492 392.077 489.981

7 N 14.534 29.601 47.448 77.472 97.888 552.057 667.029

8 0 13.618 35.116 54.934 77.412 113.896 138.116 739.315 871.387

9 F 17.422 34.970 62.707 87.138 114.240 157.161 185.182 953.886 1103.089

10 Ne 21.564 40.962 63.45 97.11 126.21 157.93 207.27 239.09 1195.797 1362.164

11 Na 5.139 47.286 71.64 98.91 138.39 172.15 208.47 264.18 299.87 1465.091

12 Mg 7.646 15.035 80.143 109.24 141.26 186.50 224.94 265.90 327.95 367.53

13 A1 5.986 18.828 28.447 119.99 153.71 190.47 241.43 284.59 330.21 398.57

14 Si 8.151 16.345 33.492 45.141 166.77 205.05 246.52 303.17 351.10 401.43

15 P 10.486 19.725 30.18 51.37 65.023 220.43 263.22 309.41 371.73 424.50

16 S 10.360 23.33 34.83 47.30 72.68 88.049 280.93 328.23 379.10 447.09

17 Cl 12.967 23.81 39.61 53.46 67.8 97.03 114.193 348.28 400.05 455.62

18 Ar 15.759 27.629 40.74 59.81 75.02 91.007 124.319 143.456 422.44 478.68

19 K 4.341 31.625 45.72 60.91 82.66 100.0 117.56 154.86 175.814 503.44

20 Ca 6.113 11.871 50.908 67.10 84.41 108.78 127.7 147.24 188.54 211.270

21 Sc 6.54 12.80 24.76 73.47 91.66 111.1 138.0 158.7 180.02 225.32

22 Ti 6.82 13.58 27.491 43.266 99.22 119.36 140.8 168.5 193.2 215.91

23 V 6.74 14.65 29.310 46.707 65.23 128.12 150.17 173.7 205.8 230.5

24 Cr 6.766 16.50 30.96 49.1 69.3 90.56 161.1 184.7 209.3 244.4

25 Mn 7.435 15.640 33.667 51.2 72.4 95 119.27 196.46 221.8 243.3

26 Fe 7.870 16.18 30.651 54.8 75.0 99 125 151.06 235.04 262.1

27 Co 7.86 17.06 33.50 51.3 79.5 102 129 157 186.13 276

28 Ni 7.635 18.168 35.17 54.9 75.5 108 133 162 193 224.5

29 Cu 7.726 20.292 36.83 55.2 79.9 103 139 166 199 232

30 Zn 9.394 17.964 39.722 59.4 82.6 108 134 174 203 238

31 Ga 5.999 20.51 30.71 64

32 Ge 7.899 15.934 34.22 45.71 93.5

33 As 9.81 18.633 28.351 50.13 62.63 127.6

34 Se 9.752 21.19 30.820 42.944 68.3 81.70 155.4

35 Br 11.814 21.8 36 47.3 59.7 88.6 103.0 192.8

36 Kr 13.999 24.359 36.95 52.5 64.7 78.5 111.0 126 230.9

37 Rb 4.177 27.28 40 52.6 71.0 84.4 99.2 136 150 277.1

38 Sr 5.695 11.030 43.6 57 71.6 90.8 106 122.3 162 177

39 Y 6.38 12.24 20.52 61.8 77.0 93.0 116 129 146.2 191

40 Zr 6.84 13.13 22.99 34.34 81.5

41 Nb 6.88 14.32 25.04 38.3 50.55 102.6 125

42 Mo 7.099 16.15 27.16 46.4 61.2 68 126.8 153

2
Table I. Ionization potentials* — Continued

Spectrum — Continued

Z

XI XII XIII XIV XV XVI XVII XVIII XIX XX XXI

1

2

3

4

5

6

7

8

9

10 1648.659 11 1761.802 1962.613 12 442.07 2085.983 2304.080 13 476.06 523.50 2437.676 2673.108 14 479.57 560.41 611.85 2816.943 3069.762 15 504.78 564.65 651.63 707.14 3223.836 3494.099 16 529.26 591.97 656.69 749.74 809.39 3658.425 3946.193 17 538.95 618.24 686.09 755.73 854.75 918 4120.778 4426.114 18 564.13 629.09 714.02 787.13 861.77 968 1034 4610.955 4933.931 19 591.25 656.39 726.03 816.61 895.12 974 1087 1157 5129.045 5469.738 20

249.832 685.89 755.47 829.79 926.00 21 265.23 291.497 787.33 861.33 940.36 22

255.04 308.25 336.267 895.58 974.02 23

270.8 298.0 355 384.30 1010.64 24

286.0 314.4 343.6 404 435.3 1136.2 25

290.4 330.8 361.0 392.2 457 489.5 1266.1 26 305 336 379 411 444 512 546.8 1403.0 27

321.2 352 384 430 464 499 571 607.2 1547 28 266 368.8 401 435 484 520 557 633 671 1698 29 274 310.8 419.7 454 490 542 579 619 698 738 1856 30

31

32

33

34

35

36

37

324.1 38 206 374.0 39

40

41

42 3
Table I. Ionization potentials* — Continued

Spectrum

z Element

I II in IV V

43 Tc 7.28 15.26 29.54

44 Ru 7.37 16.76 28.47

45 Rh 7.46 18.08 31.06

46 Pd 8.34 19.43 32.93

47 Ag 7.576 21.49 34.83

48 Cd 8.993 16.908 37.48

49 In 5.786 18.869 28.03 54

50 Sn 7.344 14.632 30.502 40.734 72.28

51 Sb 8.641 16.53 25.3 44.2 56

52 Te 9.009 18.6 27.96 37.41 58.75

53 I 10.451 19.131 33

54 Xe 12.130 21.21 32.1

55 Cs 3.894 25.1

56 Ba 5.212 10.004

57 La 5.577 11.06 19.175

58 Ce 5.47 10.85 20.20 36.72

59 Pr 5.42 10.55 21.62 38.95 57.45

60 Nd 5.49 10.72

61 Pm 5.55 10.90

62 Sm 5.63 11.07

63 Eu 5.67 11.25

64 Gd 6.14 12.1

65 Tb 5.85 11.52

66 Dy 5.93 11.67

67 Ho 6.02 11.80

68 Er 6.10 11.93

69 Tm 6.18 12.05 23.71

70 Yb 6.254 12.17 25.2

71 Lu 5.426 13.9

72 Hf 7.0 14.9 23.3 33.3

73 Ta 7.89

74 W 7.98

75 Re 7.88

76 Os 8.7

77 Ir 9.1

78 pt 9.0 18.563

79 Au 9.225 20.5

80 Hg 10.437 18.756 34.2

81 T1 6.108 20.428 29.83

82 Pb 7.416 15.032 31.937 42.32 68.8

83 Bi 7.289 16.69 25.56 45.3 56.0

VI VII VIII IX

108

70.7 137

88.3

4
TABLE I. Ionization potentials* — Continued

z Element

Spectrum

I ii III IV V

84 Po 8.42

86 At

86 Rn 10.748

87 Fr

88 Ra 5.279 10.147

89 Ac 6.9 12.1

90 Th 11.5 20.0 28.8

91 Pa

92 U

93 Np

94 Pu 5.8

95 Am 6.0

*lcm-‘

0.000123981 eV.

known for only a limited number of spectra. For the

H I and He I isoelectronic sequences, the theoretical values quoted here are well determined. Edlen,

[44], [45], [46], [47], has made a detailed study of

formulae for extrapolating ionization limits along

sequences of the lighter elements. His values are extensively quoted in Table 2. Catalan and his associates, [22 to 27], have interpolated values for spectra of neighboring elements

in the same stage of ionization. These have been

used for spectra in which series are not known.

Russell, [166], Sugar and Reader, [156], [181] and

others, have described similar general relationships

between spectra, that can be used to derive fairly

reliable limits. In Table 2 all ionization limits were recorded that were derived from observed series, from extrapolation or interpolation as described above (Edlen,

Catalan, etc.), or from theoretical calculations such

as those of the H I and He I series. When all available data from these sources had been entered, if gaps still remained for spectra of a given element

in successive stages of ionization, the intervening

limits were entered in brackets, as for TiVIII and

Ti IX. These limits, in brackets, represent calculated

values interpolated or extrapolated from observed

data, and reported in two general tables of ionization

potentials in which different methods have been

used. For scattered spectra of the elements S V

through Zn XIX, the table of Lotz, [116], has been

quoted. For larger atomic numbers, the entries in

brackets are from the table of Finkelnburg and

Humbach, [65]. No attempt has been made, however,

to quote all such calculated values.

The need for higher ionization limits within a given spectrum increases as laboratory research on absorption series in the vacuum ultraviolet, on

series produced with synchrotron radiation as a

source, and the like, advances. At the request of

workers in these fields, all components of the ground

term, and in selected cases, all levels from the

ground configuration, are entered in Table 2. All

levels above the ground state are relative to the

ground state zero. For example, in the format of

“AEL,” the lowest levels of O I are as follows:

Desig. AEL Table 2

2p 4 3 P 2 0.000 109837.02 = Limit

3 Pi 158.265 158.265

3 Po 226.977 226.977 >d 2 15867.862 15867.862

'So 33792.583 33792.583

In compiling Table 2, the energy levels of only

the ground term have been included for complex

spectra, particularly with increasing Z. It is well

known that in rare-earth spectra low configurations

and low terms overlap in many cases. Consequently,

many more low energy levels may be known than

those of the ground term. Users are urged to recognize this limitation of the Table and to consult the

literature references for further details concerning

the low levels that have been reported for individual

spectra.

As in “AEL” estimated values of energy levels are given in brackets. Similarly, ‘V’ denotes that

the energy level is not connected by observation

with the others. In Table 2, under the term designations for each

spectrum, the numbers in italics at the lower left,

refer to Table 3. This table is a Bibliography which

contains the literature references used for each

spectrum to obtain the limits and terms quoted in Table 2. 5
The importance of stating, clearly, how a limit or an ionization potential has been derived cannot be

overemphasized. It is hoped that the present tables

will enable each user to judge the quality of the

available data used to compile Table 1. Although the foregoing results are limited to optical spectra, it should be recognized that experimental values of ionization energies have, also,

been published. A surface ionization method has

been used to obtain ionization potentials for first spectra of rare earths, [196 to 198]. In general, the

agreement is satisfactory between the values obtained by the different methods.

Estimates of ionization potentials of third spectra

of the lanthanons have been calculated recently

“by applying the Born-Haber cycle to the group

3A oxides and arsenides.” [199].

After the work on the present publication had

been started, the author learned that extensive

revisions of the data on the spectra of lighter ele- ments were being prepared by B. Edlen, J. O.

Ekberg, and L. A. Svensson, in Lund. They have

most generously furnished much valuable material,

in advance of publication, for inclusion here. The

author is deeply indebted to these colleagues whose

expert judgment and advice greatly enhance the

value of the present publication. She is equally

grateful to all others who have so willingly contributed their unpublished material.

Washington, D.C.

April 22, 1970

Table 3. Bibliography

References

1. Albertson, W., Astroph. J. 84, No. 1, 26-72 (1936).

2. Albertson, W., Phys. Rev. 52, 644-647 (1937).

3. Alexander, E., Feldman, U., and Fraenkel, B. S., J. Opt.

Soc. Am. 55, No. 6, 650-653 (1965).

4. Alexander, E., Feldman, U., Fraenkel, B. S., and Hoory, S.,

J. Ont. Soc. Am. 56, No. 5, 651-652 (1966).

5. Andersson, E., and Johannesson, G. A., unpublished material (1969).

6. Andrew, K. L., and Meissner, K. W., J. Opt. Soc. Am. 49,

No. 2, 146-161 (1959).

7. Bauche, J., Blaise, J., and Fred, M., J. Opt. Soc. Am. 54,

No. 4, 565 (A) (1964).

8. Blaise, J., Fred, M., Gerstenkorn, S., and Judd, B. R., Compt. Rend. 255, 2403-2405 (1962).

9. Bockasten, K., Ark. Fys. (Stockholm) 10, No. 40, 567-582

(1956).

10. Bockasten, K., unpublished material (1963).

11. Bockasten, K., J. Opt. Soc. Am. 54, No. 8, 1065 (L) (1964).

12. Bockasten, K., unpublished material (1969). based on unpublished data communicated by Wu, C. M., and

Crooker, A. M.

13. Bockasten, K., and Edlen, B., private communication

(1970).

14. Bockasten, K., Hallin, R., and Hughes, T. P., Proc. Phys.

Soc. (London) 81 , Part 3, No. 521, 522-530 (1963).

15. Bockasten, K., and Johansson, K. B., Ark. Fys. (Stockholm)

38 , No. 31, 563-584 (1968).

16. Burgstri>m, A., Ark. Fys. (Stockholm) 38, No. 12, 243-260

(1968).

17. Bowen, I. S., Astroph. J. 121 , No. 2, 306-311 (1955); 132 , No. 1, 1-17 (1960).

18. Bromander, J., unpublished material (Uppsala 1969), from

data by Glad, S.; See Ark. Fys. (Stockholm) 7, No. 2, 7

to 32 (1954).

19. Bromander, J., and Johansson, B., J. Opt. Soc. Am. 57,

No. 9. 1158-1159 (L) (1967). 20. Bryant, B. W„ J. Opt. Soc. Am. 55, No. 7, 771-779 (1965), with revision by J. Sugar (1970). 20a. Camus, P. et Tomkins, F. S., J. de Phys. 30 , No. 7, 545-

550 (1969). 20b. Camus, P. et Tomkins, F. S., Premiere Reunion Ann. de

l'Assoc. Europeenne de Spectroscopie Atomique, Abstract 67, Paris-Orsay (1969). 21. Catalan, M. A., Meggers, W. F., and Gareia-Riquelme, O.,

J. Res. Nat. Bur. Stand. (U.S.), 68A (Phys. and Chem.)

No. 1,9-59 (Jan.-Feb. 1964).

22. Catalan, M. A. y Rico, F. R., An. Real Soc. Esp. Fis. y Quim. (Madrid) [A] 48, Nos. 11, 12, 328-338 (1952). 23. Catalan, M. A. y Rico, F., letter (Dec. 1956).

24. Catalan, M. A. y Rico, F., An. Real Soc. Esp. Fis. y Quim.

(Madrid) [A] 53 , Nos. 3. 4, 85-94 (1957). 25. Catalan. M. A. y Rico, F. R., An. Real Soc. Esp. Fis. y Quim. (Madrid) [A] 54 , Nos. 9, 10, 289-300 (1958).

26. Catalan, M. A. y Rico, F., An. Real Soc. Esp. Fis. y Quim.

(Madrid) [A] 54 , Nos. 9, 10, 301-308 (1958).

27. Catalan, M. A. y Velasco, R., An. Real Soc. Esp. Fis. y Ouim. (Madrid) [A] 48, Nos. 9, 10. 247-266 (1952).

28. Chaghtai, M. S.-U.-Z., J. Opt. Soc. Am. 59, No. 8, 969-970

(1969). 29. Charles, G. W„ J. Opt. Soc. Am. 56, No. 10. 1292-1297

(1966).

30. Cohen, L.. Feldman, U., and Kastner, S. O., J. Opt. Soc. Am. 58, No. 3, 331-334 (1968).

31. Conway, J. G., and Worden, E. F., J. Opt. Soc. Am. 58,

No. 11, 1564 (A) (1968). 32. Cowan, R. D„ Astroph. J. 147, No. 1, 377-379 (L) (1967). 33. Cowan, R. D., J. Opt. Soc. Am. 58 , No. 7, 924-933 (1968), and Edlen, B., unpublished material (1970).

34. Cowan, R. D., and Peacock, N. J., Astroph. J. 142, No. 1, 390-396 (L) (1965). 35. Crooker, A. M., private communication (December 1955).

36. Crooker, A. M., unpublished analysis (1962).

37. Crooker, A. M., and Dick, K. A., Canadian J. Phys. 46,

No. 10, 1241-1251 (1968). 38. Crooker, A. M., and Joshi, Y. N.. J. Opt. Soc. Am. 54, No.

4, 553-554 (L) (1964). 39. Deutschman, W. A., and House, L. L., Astroph. J. 144,

No. 1, 435-437 (L) (1966). 40. Deutschman, W. A., and House, L. I,., Astroph. J. 149, No. 2, Part 1, 451-452 (1967). 41. Dick, K. A., Canadian J. Phys. 46, No. 11, 1291-1302

(1968). 42. Edlen, B., Mon. Not. Roy. Astron. Soc. 114, No. 6, 700-

703 (1954). 43. Edlen, B., Trans. Intern. Astron. Union 9, 218-226 (1955). 44. Edlen, B., “Atomic Spectra,” Hand, der Phys., Encyd. of Phys. 27, 172 (1964). 45. Edlen, B., “Atomic Spectra,” Hand, der Phys., Encycl. of Phys. 27, 196 (1964). 46. Edlen, B., “Atomic Spectra,” Hand, der Phys., Encycl. of Phys. 27, 198 (1964). 47. Edlen, B., “Atomic Spectra,” Hand, der Phys., Encycl. of Phys. 27, 200 (1964).

6
387-063

0

-

70

(Face

p.

6)

No.

Table 2. Ionization limits and lowest terms

z Element

i II III IV V VI

1 H 15 2 S„„, 109678.764 68

2 He Is2 'S„ 198310.76 Is 2S„„. 438908.85 ±0.01 68

119, 169a

3 Li 2s 2 So„. 43487.150 Is2 'So 610079.0 Is 2So.„ 987660.1 ±0.005 ±0.1 49, 68 90 49, 81, 145

4 Be 2s2 'S„ 75192.07 2s 2 So„ 146882.86 Is 2 'So 1241259.4 Is

2Soi /, 1756018.7

93 92 145 68

5 B 2P 2PS,„ 66928.10 2s2 So 202887.4 2s 2S0 i/, 305931.1 Is2 'So 2092001.4 Is 2 S„,„ 2744105.1 ±0.1 ±0.8 ±0.6 49, 145 49, 68

*Pf./. 15.254 141 140

48, 142

6 C 2P

2 “Po 90820.42 2P

2 P8,„ 196664.7 2s2 'So 386241.0 2s 2 Soi/2 520178.4 Is 2 'So 3162395 Is 2 S„„2 3952061. ±0.1 2 P?.„ 63.42 ±2 ±1.5 49 ±30 49, 68

“Pi 16.40 18, 48 13. 141 9, 49, 140

"Pi 43.40

'Do 10192.63

'S„ 21648.01

94

7 N 2/i* 4 S?i/a 117225.4 2p2 “Po 238750.5 2P

2 Poi|, 382704 2s 2 ‘So 624866 2s 2 S„,„ 789537.2 Is2 'So 4452758

2 DS.„ 19224.464 ±1.3 2 P?.„ 174.36 ±3 ±3.0 49, 145

2 D?,„ 19233.177 “Pi 48.7 48, 53, 78 77, 141 76

2 ps.„ 28838.920 “Po 130.8

2 p?.„ 28839.306 d2 15316.2

55, 123 'So 32688.8 53

8 0 2/P “P2 109837.02 2p“ 4S?.„ 283240 2/P “Po 443086 2p

2 PS.,s 624383.8 2s2 'S„ 918657 2s 2S„,„, 1114008 ±0.06 2 D?i|, 26810.7 “P, 113.9 ±2.0 ±4 14, 49 ±10

•>p, 158.265 z Dn( , 26830.5 “P2 306.9 2 P°I), 385.9 15 »P„ 226.977 “Pi 1 /* 40466.9 'D, 20274 19, 48

'Do 15867.862 “Pou, 40468.4 'So 43186

‘So 33792.583 17, 46, 135 10, 17

17, 54, 57

9 F 2/P “P?.„ 140524.5 2/P “Po 282058.6 2p“ <s?.„ 505777 22 “Po 702830 2

p

2 P8.„ 921430 2s2 'S„ 1267622 ±0.4 ±1.5 ±5 “P, 225.2 -P°„ 744.5 49

2 P$.,. 404.1 “Pi 341.0 2 D?„2 34084 “Po 612.2 46,48

48, 115 “Po 489.9 2 Di«/i 34120 ‘Do 25234.4 Do 20873.4 2 p?.j 51558 'So 53537

'So 44918.1 “Poll, 1 17, 46, 135 143 135, 144

10 Ne 2p« 'So 173929.70 2/P 2 P?I„ 330391.0 2p< “Po 511800 2p“ 4 S?i/2 783300 2p

2 “P„ 1018000 2p

2 Poi/2 1273800

133 2 Poi/, 780.45 “P, 642.9 “Doc, [41217] “P, 414 2 P?.„ 1310

48. 146 “Po 920.4 2 D?„, 41262 “Po 1112 14, 46, 48

'Do 25840.8 2 Po°. (! 62417 'D, 30293 So 55750 2 p;.„ 62423 'So 63899

17, 46, 146 17, 46 17, 46

11 Na 3

5

“So,,, 41449.44 2/P 'So 381395 2p“ 2 p;.„ 577800 2p* “Po 797800 2p“ “S?,„ 1116200 2p

2 “Po 1388500 ±0.03 ± 1

2 Poi/, 1366 “P, 1105.5 2 Doi/, 48337 “P, 698

162 12 46, 48 “Po 1576 2 D?i/, 48362 “Po 1858

'Do 30839.4 2 Poi/j 73221 Do [35518]

'So 66492 2P?.,0 73260 'So [74434]

17, 44, 46, 135 44, 46, 135 17, 46, 135

Spectrum

Is 2 S„, ( , 5380089

68

Is2 l S„ 5963135

145

2s 2 S„.„ 1493629 49

2s2 'So 1671792 49

2p

2 P8.,2 1681500

2 P?„2 2139

46, 48

Is 2 Sm„ 7028393 68

Is2 'S„ 7693810

145

2s 2 S,„,„ 1928462 49

2s

2 'S„ 2130800 46

Is 2 S„,„ 8897240

68

2 'S„ 9645005

>. 145

2s 2S„, 46

2418700

i 2S0,, 2 10986876

), 68

Is2 'S„ 129

11817061 Is

2 S„,„ 13297676

68

6a
TABLE 2. Ionization limits and lowest terms — conliniicd

Specimen

, II III IV v VI VI. VIII IX. x XI XII XIII XIV XV XVI XVII XVIII XIX XX XXI

“h, 35 121267.61 s, 616110 2,,' »pt.„ 881100 2p' *P3 1139400 2//' 'ST,,, 1504300 2/»* »Po 181-1300 2p 'P?„ 2141700 2s= 'So 2645200 25 'So,,, 2964400 Is* 'So 14210261 Is ’So,,, 15829951 + 20 M’S,,, 2227 'P, 1780 *DT„, 55245 ’Pi 1127 -PT. 3302.2 46 49,68

10. 48 'Po 2519 »D?.„ 55266 "Pi 2939 46, 18 'Dj 35890 >Po.„ 83805 'Di [41003] S„ 77254 *P?.,, 83927 'So [85191]

44, 46. 135 14. 46. 135 17. 46, 135

13 35' 'So 151860.4 35 ,snii 229445.71 2p* 'So 967800 2/,* *P? ,1239800 2

/,' 'P- 1536300 2//* 'ST, ,, 1947300 2p- 'P„ 2295400 2p >PS„, 2663400 2

s* 'So 3211800 2s 'So., 3565600 Is* 'So 16825022 Is ’S„,/, 1858-1138 -0.5 ±0.2 'PS , 34-12 *P, 2736 62080 'P, 17-10 ’P?.„ 1890 •16 129

1,15 87 46. 18 *Po 3831 'Di„, 621-10 'I*. 4140 -16. 48

St> 'D3 41140 *Po.„ 91380 16. 135

'So 88210 *PT.,. 94650

44, 46. 135 44, 46, 135

W *1*8./. 131838.4 35» •So 270139.3 3s *So,„ 364093.

2p* 'S„ 1345100 2/>' *Pf,„ 1653900 2p' 'P. 1988400 2/P 'ST., 2415300 2p= ’Po 2831900 2p ’Po,,, 3237800 2s* 'S„ 3839800 2s *So.„ 4222400 Is* 'So 19661693 Is *So,„ 21560630 ±0.1 ±0.4 ±0.6 »PS.„ 5097 'Pi 1030 -•D?, 67 140+ a *P, 2590 *P?,„ 6988.7 46 46 129 49. 68

PT.,, 287.32 186 185 'Po 5570 'Di. 67420+.* 'P, 46. 48

223.157 172 'D.. 16550 'PS. 103320+1 16. 135

If, 6298.85(1 'So 99330 'PT, 103900+

•s. 15394.370 44, 46. 135 46, 135

l> *ST„ 84580 3P« »l*o 159100 3

p

*P8„ 243-HK) 3

s' s„ 414312.4 3s 'S„. 524160 2pn 'So 1777900 2!p» 'P?,,. 2123100 2/»« ’P ; 2495600 2p’ *S?.„ 2998300 2p* 'Po 3423900 2p *P8„ 3868100 2s* 'So 4520100 2s 'So.,, 4935000 Is* 'So 22720766 Is «So,„ 24759942

11360.8 *1*. 16-1.8 559.6 135 45 'Po,,, 7268 •P. 5757 'Di,,, 73167 'P, [3705] 9700 46 129 68

11376.4 *1*. 469.0 17. 13. 16. 18, 135 *P„ 7826 'DT„, 73730 'P, [9050] 46. 135

•PJ„ 18722.65 'Dj 8882.6 'Di 52450+.* J Po„, 113457 'D. 59330

«PT„ 18747.95 S„ 21576.2 'So 1 10970+* ’P?,„ 114430 'So 119430

iir IIR •16. 135 •16. 135 42. 46. 135

s ’I*. 83558.0 3,,' 'ST„, 188200 3p* i|.„ 280900 3P Pin, 381541.4 3s' 'S„ [586200] 3s 'S„,„ 71018-1 2p» 'So 2265900 2/P 'PT,, 26-17400 2

p' 'P, 3057700 2p’ ‘Si„, 3606100 2p* 'Po 4071400 2p *Po„ 4554300 2s* 'So 5255900 2s >So,„ 5703600 Is* 'So 26002663 Is ’S*,„ 2818253S

'P, 396.09 'Dm, 14853.0 ’I’, 297.2 »pf.„ 950.2 110 45 *PS„ 10087 »P, 7970 *D?„, 77670+* 'P, 5200 *PT„ 13135.3 46 129 49,68

’D?„ 1-1884.8 B32.5 135 46. 18 'Po 10630 *D!,„ 788(H) +* 'Pi 12100

9238.58 ’Po„, 24524.9 'll. 11320.8 'D. 58000+s 'PS„, [122230]+* 10, 46

22)79.99 *P!.„ 24571.6 'So 27159.1 'So 1 22300 +* 'PT,,, 124080+*

HR. OR 17, 47 17, 47, 135 •16. 135 40. 46. 135

17 Cl •PT„ 104591.0 3/.' »l»t 192070 3p* 4STi, 319500 3p« 'P„ 431226 3p *P8, 547000 3s' 'So [782600] 3s 'So,„ 921051 2/P 'So 2809100 2p* »P?„, 3226700 2p' ’P, 3674900 2p' ‘ST>, 4268900 2p* 'I’o 4774700 2p »Po°„, 5296700 2s’ 'So 60-47200 2s *So,„ 6528300 Is’ 'S, 29507950 Is ’S„„ 31829012

3P, 696.

'DV., 18053.0 >p, 491 ’PT. 1492 11

45 'Po,,. 13641 'P. 10880 *DT, 91960+1 'P, 7200

*1*8./ 882,36 996.4 '1)«, 18118.6 'Pi 1341 135 46. 18 »Po 141-10 *DT, [94000]+* 'Pi 16600 46

151 •1).. 1 1653.5 29812.8 'll, 13767 •Di 61000+* *PS, 141150+* 40, 46

27877.8 *PV„ 29905.6 32547 •S„ 130310+* *PT. 1 44200+*

47, OR 17,47 17. 135 39, 46. 135 40. 46

1H Ar 3/,- 'So 127109.9 3/>s *PT.fI 222848.2 3p* 'Pi 328600 3p> «ST,„ 482400 3/, » 'P„ 605100 3p 'Po.„ 734040 3s' 'So 1002730 3s 'So,, 1157080 2p« 'S„ 3-107300 2p* *PT.„ 3860900 2p' »P, 4347000 2p* *ST„, 4986600 2p* 'Po 5533800 2p *PS„ 6095500 2s’ 'So 6894200 2s >So,„ [7404-100] Is’ 'So 33237173 Is *So.„ 35699936

±0.1 *PS.„ 1431.41 »P, 1112.1 *l)i.„ 21090.7 'P, 765 'P?,„ 2208 52 52 46 *PS„, 18067 'Pi 14390 4(1. 46 9900

135, 101 130 '1*0 1570.2 •D*;, 21219.5 'P, 2030 52 46, 48 'Po 18230 'Pi 21900 42. 46. 48

'D, 1 4010.0 »Po'.„ 34856.2 •Di 16300 39. 46 40,

33265.7 *PT.„ 35033.1 'So 37913

17.47, 135 17. 135 17. 135

19 K 4j 'So.,, 35009.77 'So 255076 3

/>* ’PT„ 36881X1 3p' 'P, 491300 3

p' 'ST„ [666700] 3/;' 'P„ 1806600] 3p »PS„, 948200 3s' ‘So 1249100 3s 'S0.„ 1418070 2

p« 'So 4060600 2p* *PT„ 4550100 2/>‘ 'Pi S074100 2p» •ST„, 5759100 2

p* 'P„ 6348800 2p ’P?,„ 6950800 2s* 'So [7807600] 2s *So„, [83-10000] Is’ 'S„ 37190818 Is ’So,,. 39795865

±0.02 134 2166 'P, 1673 *Df, 24012.7 *P, 1132 «P?,„ 3133 52 52 46 *P?„ 23475 'Pi 18970 46

162 52, 182 »P, 2325 *d;„ 24249.5 'P: 2924 52 46. 48 'Po 23250 46

'D, 1638-1.0 'PS., 39758 'Dj 18978 40. 46. 59

'So 38546.2 *p?„ 10077 52. 11 6. 135

17. 135, 182 17, 116

20 Cu 4,! 'So 49305.72 4s ’So,,, 95751.87 3p* 'So 410614.1 •P*./, 3/,’ '1»„ 1030000 3/> 'P?„, 1187600 3s* 'So 1520700 3s »S„,„ 170-1050 :2p « 'So 4768900 2p» *PT„ 5294300 2p' 'Pi 5856000 2p' ‘ST., 6586600 2p' 'Po 7219800 2p >PS.„ [7856000] 2s’ 'S„ [8767000] 2s *So.„ [9332000] Is’ 'S» 41369608 Is 'So,,, 441 17547

-0.03 16 *PS.„ 'Di„, 26851 'P, 1628 •PT„ 4301 52 52 46 »PS„ 30014 *P. 24460 50 16. 52 'DI,,, 27267 '!>. -1075 52 46. 48

'D-, 18830.52. 116 'D2 21864 46. 59. 89

17. 135. 182 52. 135

6b
Table 2. Ionization limits and lowest it

55010

170.132 386.874

'F,,„ 51400

«F2,„ 137.38

'K,,,, 323.42

4Fn,, 553.02

3 d’ 4s’ “D4 63480

“D3 415.932

sDj 704.003

s Di 888.132

S D„ 978.076

I

Ij* *F4 „, 63430

«F3 ,„ 816.00 *F„„ 1406.84

•F,i/, 1B09.33

61579

1332.153 2216.519

103240

67.68

177.63 2540.97

<F,„, 109506 «F„„ 93.94

4 F3 .„ 225.47

‘F,,,, 393.22

118200

36.05

106.63 208.89

339.21

8473.5

10538.4

10603.6

10721.2

145.5 341.5

583.8

„ 130524

„ 384.77

„ 667.64

„ 862.63

„ 977.03

137572

950.45

1597.20

247221

436.2

738.9 932.4

1027.3

283700

1360.7 2269.6

3F3 325.4

3F, 734.7 Dj 10959.3

*F„(1 [396000]

4Ffi/, 244

*F3 .,, 561

4 F4 „, 956

3d* 5 D0 [413000]

3d* "Sji,, [442000]

3d* 5 D4 [413800]

'P?.„ 739300

'PS„, 4318

52. 182

3d *D,i„ [526100]

3d’ 3 F2 [559000]

3d3 'F,,,. [584000]

3d* 5 D0 [604900]

116, 136

3d5 «S 2„, [641200]

3d6 5 D4 [609000]

3d’ 4 F41/i [644500]

3348

4458 21398

3p» 'So 1033400

3d1 ’Ft [766000]

3d’ «S 2„, [871000]

3

</« ’D, [831000]

3p’ ^.[lmiOO]

s D?i/I 29565

’Dli,, 30247

52, 11

1136000 4530

5884

24130

3p’ ’P?.„ 121 1200

«PS.,, 7660

52, 135

3d’ ’Ft [1008000]

3d’ 4 F„„[ 10400001

*F3„,

4F41,, 116, 136

3d* 6 D0 [10730001

3d’ «S,„J1 121000]

1280000 2272

5505

25035

4S°„„ 1359000

’D?„, 32168

:D?,„ 33239

31>* 3Pi 1401000

'P, 6000

>P„ 7580

'D. 27120

3p’ -P?„, [1490000]

!PS„, 9900

116, 136

3

p° ‘So [1584600]

3d 2D,i„ 1218-100

3D2 ,„ 1850

3, 32, 34

3d’ ’Ft [1266000]

3 Fa 1430

’F< 3140

3d’ *F„„ [1307000]

3d* “Do [1339000]

'Po [1558000]

•P, 3125

>P 2 7291

'Ds 28557

52,116, 183

3p’ <Si.„ [1659900]

3p* 3Pi [1688000]

3 P, 7860

3 P0 9600

116, 136

3p’ J P?.„ [1789000]

*PS.„ 12530

116, 136

3d >Di.„ 1501300

*Dji,, 2440

3, 75

3d’ ’Ft [1557000]

3s’ 'So 1817400

[1859200] 4310

9540

3

p

3 *S°„„ [1971000]

[2003000]

10000

11700

3p« 'So 2230000

3d J D„„ 1811000

3 Dti„ 3150

3, 67

[1871000] 2485

5465

3p’ “Po [2184000]

2342000

12667.9 14440

3p’ JP?.„ 2462000

’Po.,, 19420

75. 136

3d *D|i„ 2146000

2p« 'So 5532200

3j ’S0.„ 2351140

3p ’Po.„ [2403600]

’P?,„ 12200

60, 116

3p’ 3 P» [2535900]

2p* 3P, 6692900

2p’ >P?„, 6947300

Po.„ 47190

46, 59

3s ’So,i, 2712250

3s «S,.„ 3099630

3p ’PS.,, [2771400]

Pi.,. 16400

62. 116

3

p’ 3 P0 [2912000]

3p4 3 P2 [2710000]

3p’ *P?.„ [2839000]

"Po.,, 23627.3

89, 116

3

p« 'S„ [2975000]

3 P2 [3097000]

3 P, 19541.8

3 P„ [20200]

89, 116, 136

2/,’ «S?.„ 7468900

2p* “P, 7584700

35 »So,„ 3511210

3p *PS„, [3163000]

‘P?.,, 18850.6 89,116

3p> *S?„, [3468000]

2

p* 'S. 9164300

3j 'S0.„ 3947840

[3742500]

14917.5 27376.5

3p «PS.„ [4025000]

’P?,„ 27761.4

89, 116

3/>’ ‘Sf.„ [3904000]

2p • 'So 10211700

2p‘ 'S, 11316400

3s’ 'So [4606000]

3p «P*.„ [4493000] 3s’ 'So [5106000] 3i *So.„ 5410000

6c
Table 2. Ionization limits and lo

557.1341

1409.9609 7125.2989

16367.3332

78658.22

1989.49 2534.35 9576.08

22446.03

•P?,„ 95284.8 ±0.5

•PS,,, 3685.24

•F, 55145

•F, 570.41

•F, 1240.84

•PS,„ 128521.3 ±0.2

«P?.„ 1767.356

2538

10097 22602

P, 175870 P, 3136.4

'Po 3837.5 D, 12089.1 So 27867.1

'So 320390

4j» 'So 276036

•P, 4548

•Po 5313

'D, 14644

4 F|,„ 105900 *F„„ 314.67 'F„„ 763.44

‘F4„, 1322.91

3rf'° 'S„ 517600

4d *D„„ 276970

3d10 'So 753800

41> 'PS,,, 346375

*P?,„ -4376

36, 136

•P„ [381600]

•P, 3247

»P, 6237

•D, 18115

4p» *S?„, [423600]

3d' *F4 ,„ [871000]

•Fj,,,

4 Fj,,,

4p •PS,, 1 [481600]

•P?„, 6090

65, 136

4!> •Po [522000]

4ps «S?.„ [572800]

4p* 'P, [577700]

4p» >P?„, [621200]

•PS,„ 12459.9

65. 155

3d'° 'So 1028800

4j 'Sow, 658994

4s' 'So [714800]

4p 'PS, „ [633300]

•Pf.„ 8108 61.65

4p- •!’„ [680900]

4p' *S?.„ [732600]

4p* •!', [750300]

3 d

i CS3 ,„ [1403000]

3d‘° ‘So 125:3300

4s 'So./, [831000]

4s' 'So [895500]

4p 'PS.„ [800300]

4p: 'Po 1855200]

4p3 4 S?,„ [935900]

3 d

,a 'So 155*4700

4s= 'So [ 10980(H)]

3d' 5D„ [1637000]

3tf'° 'So 1862400

3d1 *F„„ [1920000]

3 'So 2235100

4p 'PS.„ [1179500]

3d'- 'F, [2210000]

•Fi 3030

•F, 6735

58, II

3p« 'So [3385000] 3p* 'Ptw. [3662000] 3p’

'I’o [4670000] 3p [4993000] 3s' 'So [5630000] 3s 'S„„ 5952000

3d'° 'So 2613800

1
Table 2. Ionisation limits and lowest terms — continued

«D;.„ 391.99

«DS,„ 695.25

•D;.„ 1050.26 22

W’ 5s 'Sa 57260

5s» «Sj,„ 58700

137

4d’ Ss 5F» 59410

‘Ft 1190.64

s F3 2091.54 ‘Fa 2713.24

‘F, 3105.49

101

4d» 5j •f\,„ 60197

•F3„, 1529.97

•Ft,,, 2598.03

•F ii,, 3472.68

S5« 5p ’PS,„ 46670.11

59231.8

1691.8 3427.7

72667

4751 4707

Spectrum

II HI IV v V. VII vm

5 D<> 115500

*D| 158.99 ‘D, 438.38 ‘Da 801.38

‘D. 1224.87

4d* •F„,1 202000 •F„„ 515.8

•F>.„ 1176.6

•Ft,„ 1939.0

24, 82

4d'

136

‘Ft 308600

»FS 1086.4 ’Ft 2344.6

4d ‘Dm,, 407700

*Dt„, 1870

104, 136

4p* 'So 827300

28

4p» «PJ,„ 1005000

>PS„, 19199

28. 136

•S,,,. 130300 ‘Do 219100

‘D, 243.10

‘D, 669.60

5 Dj 1225.20

‘D, 1873.80 158

id1

137

•F,,,. 374180 •F„„ 780.0

4

Fji/, 1759.0

•F,,,, 2858.6

4d' sF2 493360

‘F, 1585

’F« 3359 137

4d ’Du,, 549000

’Dt„, 2578

104, 137

4p" 'So 1022800 28

4p‘ ’P?,„ 1235000

’PS,„ 23273

28. 137

’Sj 123100 4d> «S,.„ 23&100 24

4F<.,, 135200

•Fj,(1 1523.1

•Ft,,, 2493.9 •F„„ 3104.2

4d* ‘Dt 229600

5Da 1158.8

‘Ds 1826.3

‘D, 2266.3

»D« 2476.0 137

‘Ft 145800

‘Ft 2401.3

‘F, 3580.7

4dJ 4Ft„, 250500

•FS , (I 2147.8 •F„„ 3485.7

4F„„ 4322.0

84. 137

!Dn,, 156700 ’D„„ 3539

4d" ‘Ft 265600

’Ft 3229.3

•Ft 4687.5

173

So 173300 4</“ *D*.„ 280900

'D|,,, 4607

137

‘So,,, 136374.74 4<i 10 >S0 302300

137

So 152195 5i ‘So.,. 226100

137

4d'<> 137

'So '139000

’PS,,, 118017.0

*Pf.„ 4251.4

5** 'So 246020.0

137

5s137

«So.„ 328550.0 4</"> 'So 583000

137

’P„ 133327.5

>P, 3055.0

‘P, 5659.0

Ss* 5p’PS,„ 204248

’Pt,„ 6576

137

Ss' 137 So 356156 5s 'Soil, 449300

137

4d"> 'So 868000

137

•S?,/, 150000 ±3000

5p« J Po 225500

>P, 4756.5

‘Pt 8166.9 38

55*

38

5p’PS„, 301776

«P?.„ 9222.6

5s' 'So 473900 385s ‘So,„ 570000 38

4d'<> 'So 1107000

137

‘P, 154304 ±1

‘P,

- 7087.0 ‘P0 6447.9

5

p> 4S?.„ [266000] 65
n limits and lowest li

31406.432 ±9.010

5d 6

s* *Di.,

*0,,, 72. 137

if Sd 6s1 'GS

120, 156a

43730 ±150

1376.54

2846.61

44270 ±150

1128.055 2366.595

3681.690

5048.605

44800 ±150

803.82

1748.78 2797.10

3919.03

5089.79

292.58

811.92

1489.55 2273.09

2, 1 56

4p 6s l

±650

1016.10

1970.70

4f 5d* *H!.„ 87500 ±650

«HS.„ 987.62

1873.95

«HJ,„ 2382.26

80, 149, 181

4P 6s MS 85100 ±650

MS 441.94 MS 1649.01 M? 2998.31 MS 4437.09

513.330

1470.100 2585.460 3801.935

5085.650

87900 ±650

446.45

1133.45

1983.52 2950.31

•F,,,, 838.22 "F„/t 1489.16

*F,.„ 2237.97

*Fa .,, 3052.65

259089

9794.6 8131

5d 6***D,,„ 154664

4p MS.,. 174-420 ±130

MS.,. 1398.34

MS.,, 2893.14

M?.„ 4453.76

4/ *F1.,, 463400 ±400

FS.„ 3027.4

6f
z

64

65

66

67

68

69

70

71

72

73

1

Table 2. Ionization limits and lowest n

215.13 532.98

999.11

1719.06

3H4 117, 156

4f

a 6j* *F5,/

126, 156

4/'* 6j» >S,

20a

JF!i,

49210 ±150

6958.34

10750.99

49840 ±150

8771.25

56600

2356.68 4567.64

‘Fni, 63600

<F,i„ 2010.10 <Fa „, 3963.92

<F 4 ,„ 5621.04

31, 181

4/" 6i

125, 181

4/,J 6s

126, 181

4/M 6s

633.27

1158.94

1935.30

94100 ±650

4341.10

7485.09 7463.88

9432.07

10953.94

97200 ±650

236.94 8769.69

»F?.„ 8774.02 180a

4f<* 'So 203300

187800

3288.7

6095.1

6g
Table 2. Ionization limits and loivest terms — continued

Spectrum

5d

4 6s2

114, 137

5d* 6s2

137

5 D0 64400

5Di 1670.29

5 D2 3325.53

5 D3 4530.00

5 D< 6219.33

eS21/, 63530

Pt

Pb

Po

Ac

5d

6 6s2 5 D< 70450

s d3 4159.32

s d2 2740.49

5 D, 5766.14

5 D0 6092.79

108, 137

Sd7 6s2 'F,,,, 73000 ±800

4Fj„, 6323.96

4 F2 ,„ 5784.63

4Fn/ 4078.95 107

5d9 6s 3 D3 72300

"Do 775.9

3D, 10132.0 137

5d'° 6s 137

2So„. 74410.0

6s

2 'So 84184.1 137

6s2 6p

! PS./. 49266.7 ±0.1

157 ! p;./. 7792.7

6p2 3Po 59819.4 ±0.3

3Pi 7819.2626

189

3 P2 10650.3271

6p3 4s;,„ 58790

137

6p* 3 P2 67885.3

3 p, 16831.61

29

"Po 7514.69

6

p

6 ‘So 86692.5 137

7s2

137

'So 42577.35

6d Is2 ! D,„. [55600]

65, 137

Z U2l/j 2231.43

7s137

Is2

137

5d°

137

5137

5d10 6s 137

6s2

137

6s

2 6

p

137, 189

2 D21/ , 149723

2 Dii/2 8419.9

'So 165000

2S0i/2 151280

•So 164765 ±5

2Po.„ 121243 ±3

2 P?'/2 14081.074

6P

2 3 Po 134600

3Pi 13324

137

3P2 17030

5137

6s137

6s2

137

‘So 276000

2 So ./. 240600

'S„ 257592 ±5

632 2 PS„, 206180

2 P?„ 20788

137

“So.,. 81842.31

'So 97300

6s137

“So.,. 341350

6s" ‘So 365500

137

3d'° 'S„ 555000

137

6s 2 S„,„ 451700

137

5d‘» '

137

6h
Table 2. Ionization limits and lowest terms — Continued

Element

91

92

93

Th

Pa

U

Np

3F2

3F3 3F4

2869.260

4961.661

65, 124

5P 752 7Fo 47000

7Fi 2203.55

7F2 4299.55

7F3 6144.34

7F, 7774.45

7FS 9179.05

7FS 10238.24

7, 8

5/7 7s2 “SI.,. 48770

66

Spectrum

II

4Fn/t [93000] 6d

2

4F21/2 1521.91

4 F3 , /2 4146.57

4 F41/j 6213.55 109

in

3F2

3 F:i 3F4

161000

3992.7 6474.9

5/

112

IV

2F§i/z

2Fli/a

v VI

231900

4325.38

o

6i
, m £

' . ...

H.l -

- •• - -

.

•! *
References — Continued

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7
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129. Midtal, J., and Aashamar, K., Norvegica 2, No. 2, 99—109

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59 No 4 494-443 I1Q69)

152. Rao, Y. B„ Indian J. Phys. 32, No. 11, 497-515 (1958). 153. Reader, J., and Davis, S. P., Program, Atomic Sp. Symposium, Nat. Bur. Stand. (U.S.), p. 79 (A) (1967). 154. Reader, J., and Davis, S. P., J. Res. Nat. Bur. Stand. (U.S.), 7 1 A (Phys. and Chem.) No. 6, 587—599 (Nov.—Dec. 1967). 155. Reader, J., and Epstein, G. L., J. Opt. Soc. Am. 60, No.

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