bluuebunny/crossref_metadata_2025 huggingface dataset:
Configuration Interaction in the Lithium Hydride Molecule. I. A Determinantal AO Approach
Authors: Karo A. M. , Olson A. R.
Published: January 2005

Numerical Hartree-Fock lithium orbitals and a 1s exponential hydrogen orbital have been used as basis functions for determining eigenfunctions for the LiH molecule. The calculations were carried out for both the ground electronic state and the first excited electronic state at nine internuclear distances. A configuration interaction treatment was superimposed on the valence-bond, ground-state calculation. Determinantal functions were constructed for the states of the system, the Hamiltonian matrix calculated between these states, and the corresponding secular determinant solved for the eigenvalues and corresponding eigenvectors. The total molecular energy, binding energy, and dipole moment were determined as functions of the internuclear distance. Where possible, comparison is made with experiment and with other theoretical work.
Configuration Interaction in the Lithium Hydride Molecule. II. An SCF LCAO-MO Approach
Authors: Karo A. M.
Published: January 2005

Numerical Hartree-Fock lithium orbitals and a 1s exponential hydrogen orbital have been used as basis functions for a self-consistent field molecular orbital calculation of the electronic structure of the LiH molecule. The molecular orbitals were approximated as linear combinations of the atomic orbitals. Calculations were carried out at nine internuclear distances for both the ground state and the first excited state. Configuration interaction was included with the restriction that the 1σ molecular orbital remains filled. Comparison is made with the determinantal atomic orbital calculation reported in an earlier paper.
Vibrational Spectra of Primary and Secondary Aliphatic Amines
Authors: Stewart James E.
Published: January 2005

The infrared absorption spectra of twenty primary and thirteen secondary amines have been studied. A strong band, assigned to the asymmetric C–N stretching mode of secondary amines, is found at 1139±7 cm—1 in compounds having a primary alpha carbon and at 1181±10 cm—1 in compounds having a secondary alpha carbon. The primary amines have a corresponding C–N band at 1079±11, 1040±3, and 1030±8 cm—1 for compounds with primary, secondary, and tertiary alpha carbons, respectively. A strong broad band is found at 739±11 and 718±18 cm—1 in the spectra of secondary amines having primary and secondary alpha carbons. This absorption is assigned to the N–H bending mode. In liquid primary amines, pairs of strong bands at 778±15 and 825±15, 794±16 and 840±11, and 776±8 and 833±18 cm—1 are assigned to the symmetric and asymmetric NH2 bending modes in compounds having primary, secondary and tertiary alpha carbon atoms, respectively. Shifts in frequency of some of these bands are noted in the gas phase or in solution. A very strong, broad band centered at less than 290 cm—1 is observed in the spectra of the primary amines, but not the secondary amines. This band disappears in the gas phase and is assigned to the torsional oscillation of the —NH2 group.

A simplified normal coordinate treatment of the R—NH2 and R2—NH vibrations is given in support of the assignments.
Molecular Motion in Polyethylene. II
Authors: McCall David W. , Douglass Dean C. , Anderson Ernest W.
Published: January 2005

Nuclear magnetic relaxation times T1 and T2 have been measured in various polyethylene melts to 200°C. Two distinct T2's can be resolved in all cases but single T1's have been found. T1 is never equal to T2. A self-consistent explanation is offered in terms of the theory of Kubo and Tomita as modified by (1) the assumption of a very broad distribution of motional correlation times, and (2) the assumption of a ``two-phase'' structure of the polymer melt.
LCAO-MO SCF Study of B2
Authors: Padgett Alice A. , Griffing Virginia
Published: January 2005

An LCAO molecular orbital study of B2 was made for three distances of the internuclear parameter. SCF molecular orbitals were obtained for the 3Σg— state, which is the reported ground state of the molecule. Total molecular energies of other low-lying states were calculated using the 3Σg— SCF molecular orbitals. These results indicate that the 5Σu— state is the ground state of B2; however, the 3Σg— and 3Πu states lie only about 1.5 ev above the 5Σu— state and may become lower in a more refined calculation.

A Mulliken electronic population analysis was applied to B2. For comparative purposes a summary of overlap and atomic populations of Li2, C2, N2, and O2 is included.
Pure Rotational Absorption of Ozone and Sulfur Dioxide from 100 to 200 Microns
Authors: Danti Alfred , Lord R. C.
Published: January 2005

Pure rotational absorption spectra of ozone and sulfur dioxide (100-200 microns) have been correlated with the microwave reciprocal moments and the distortion constants through Polo's first-order treatment of centrifugal distortion. A small grating spectrometer was used to record five weak Q branches of O3 and about eight due to SO2. The SO2 spectrum is complicated by relatively strong associated P and R branch lines. The values of the most important distortion constant, DK, are found to be 1.96×10—4 and 7.61×10—5 for O3 and SO2, respectively. The respective values calculated from the centrifugal distortion constants are 1.95×10—4 and 8.54×10—5 cm—1. The five other distortion terms were also calculated. The ease of obtaining reasonably accurate molecular constants from far infrared investigations is pointed out and theoretical treatment of SO2 is suggested.
Single-Center Wave Function for the Hydrogen Molecule
Authors: Hagstrom Stanley , Shull Harrison
Published: January 2005

The ground state of the hydrogen molecule is studied using an expansion based on a single center, the molecular midpoint, with basis orbitals constructed from associated Laguerre functions with a single orbital exponent. The convergence of the expansion is studied by systematic addition of terms and is found to be slow. The best wave functions attained have energies of —1.15086 (38 axially symmetric terms), and —1.16141 (44 terms). The results are shown to be very similar to those obtained by using Slater orbitals with nonintegral principal quantum number both from the energy increments observed and from a natural spin orbital occupation number analysis. It is concluded that the slow convergence probably results from failure to represent adequately the singularities at the nuclei, and that further use of single-center expansions in diatomic problems (except at very small internuclear distances) seems unprofitable, irrespective of what set of orbitals is used as a basis.
Electronic Structure of Some Group III Halides from Pure Quadrupole Resonance Measurements
Authors: Casabella P. A. , Bray P. J. , Barnes R. G.
Published: January 2005

The Al27 pure quadrupole resonances in AlBr3 are reported. With the addition of these data, the quadrupole coupling constants of all the atoms in the structure of five group III halides are known. For these cases it has been possible to determine complete self-consistent electron distributions for the molecules. In addition, for two of the compounds it has been possible to determine bond angles and establish the existence of bent bonds in the molecules.
Energies and Vibrational Frequencies of Gaseous Alkali Halide M2X+ Ions
Authors: Milne Thomas A. , Cubicciotti Daniel
Published: January 2005

A potential function describing the interaction between the ions of M2X+ molecules has been developed using a model suggested by Pauling. From this potential the energies and vibrational frequencies have been calculated for these molecules. The harmonic contributions to the bending frequencies are shown to be far from negligible based on this purely ionic model. The entropy and free energy changes for the reaction M(g)++MX(g) → M2X+(g) are considered.
Optical and Electrical Properties of Single Crystals of Tri-p-Methoxy Phenyl Methyl Perchlorate and Triphenyl Methyl Azide
Authors: Evans B. L. , Yoffe A. D.
Published: January 2005

Measurements have been made of the optical and electrical properties of single crystals of tri-p-methoxy phenyl methyl perchlorate and triphenyl methyl azide. These include the absorption spectra, photoconduction behavior, low-frequency dielectric constants, and refractive indices. In the case of tri-p-methoxy phenyl methyl perchlorate where the electron affinity of the acid radical is high the solid is ionic and an estimate has been made of the energy required to raise an electron from the full band to the conduction band. The properties of triphenyl methyl azide are consistent with a covalent type solid. The stability of these compounds is considered in outline.
Transport Phenomena in a Fluid Composed of Diatomic Molecules
Authors: Dahler John S.
Published: January 2005

It is illustrated that the formal theory of transport processes developed by Kirkwood, Irving, Zwanzig, and Ross can be extended to fluids composed of polyatomic molecules. In Secs. II and III the hydrodynamical equations are established for the case of classical mechanics and in IV these same relationships are shown to obtain in the quantum theory. Section VI is devoted primarily to the equations of change for the classical distribution functions, special attention being given to cases where the intermolecular forces are impulsive. In V and VI the quantum theory is formulated in terms of generalized Wigner functions, i.e., Fourier transforms of the density matrix. In terms of these functions the transport properties of a dilute polyatomic fluid may be represented as those of a mixture whose components are molecules with different internal quantum states. Finally, in VII we consider the equations of change for the Wigner functions and the quantum analog of the Boltzmann integro-differential equation.
Thermal Expansion of 〈UN〉, 〈UO2〉, 〈UO2·ThO2〉, and 〈ThO2〉
Authors: Kempter Charles P. , Elliott Reed O.
Published: January 2005

The thermal expansion characteristics of polycrystalline 〈UN〉, 〈UO2〉, 〈UO2·ThO2〉 solid solution, and 〈ThO2〉 were determined between room temperature and ca 1000°C by means of x-ray diffraction techniques. For the range 26° to 1000°C, the values of the average linear thermal expansion coefficients (ᾱ×106/∘C) are 8.61, 10.52, 10.18, and 9.32, respectively. A comparison of the observed 〈UO2·ThO2〉 lattice constants with those calculated by the method of E—an Zen indicates that the solid solution becomes less ideal as the temperature increases.
Microwave Spectrum, Barrier to Internal Rotation, and Structure of Methyl Formate
Authors: Curl R. F.
Published: January 2005

Rotational constants have been assigned to the following isotopic species of methyl formate by investigation of their microwave spectra: HCOOCH3, DCOOCH3, HCOOCH2D, HCOOCD3, HC13OOCH3, HCOOC13H3, HCO18OCH3, and HCOO18CH3. The following structural parameters were obtained from these rotational constants: r (C=O) = 1.200±0.01 A, r (C–O carboxyl) = 1.334±0.01 A, r (C–O methoxyl) = 1.437±0.01 A, r (C–H carboxyl) = 1.101±0.01 A, r (C–H methyl) = 1.086±0.015 A, ∠O=C–O=125°52′±1°, ∠H–C–O (carboxyl) = 109°18′±1°, ∠C–O–C = 114°47′±1°, and ∠H–C–H = 110°40′±1.5°. The carbon-oxygen skeleton is planar with the methyl group cis to the carboxyl oxygen. The methyl group axis has been assumed to be along the C–O (methoxyl) bond, although some evidence suggests that it may be tilted.

The barrier to internal rotation of the methyl group was calculated from the splittings observed in the rotational transitions of the ground torsional state for several isotopic species and found to be 1190±40 cal/mole.

The dipole moment was calculated from the observed Stark effect and found to be 1.77±0.03D. The dipole moment lies at an angle of 39.4±2° from the C=O bond and roughly on the line between the ester oxygen and the carboxyl oxygen.
Theory of Pressure Effects on Alkali Doublet Lines
Authors: Klein Lewis , Margenau Henry
Published: January 2005

Experiments have revealed that pressures of noble gases cause bands to appear in both the red and violet wings of the alkali doublet lines. The present paper is devoted to the explanation of these bands and to the shift and shape of the doublet lines which they accompany. In order to examine various qualitative proposals previously put forth to this end, we first ascertain the validity of the statistical theory as applied to the magnetic substates of the alkali resonance lines and develop a criterion for adiabaticity. This criterion indicates that the earlier theories are inadequate. Shift and broadening of the two components of the alkali doublet lines are then calculated as functions of noble gas density by considering the van der Waals energy perturbation due to n simultaneously acting perturbers. The conclusion, which is in agreement with experiments, is that the P322 resonance line is shifted and broadened more than the 2P½ resonance line at moderate pressures. A phenomenological approach is used to construct a more reasonable theory of the ``satellite'' bands. In the absence of reliable knowledge concerning the repulsive portions of the interaction curves, only a semiquantitative understanding of the data is achieved.
Rate of Reaction of Hydrogen with Iodine at Equilibrium
Authors: Sullivan John H.
Published: January 2005

Rosenbaum and Hogness [E. J. Rosenbaum and T. R. Hogness, J. Chem. Phys. 2, 267 (1934)] measured the rate of para to ortho hydrogen conversion in equilibrium mixtures of hydrogen, iodine, and hydrogen iodide and found that the conversion rates were about twice as fast as would be predicted by the reactionsH2+I2↔ lim (2)(1)2HI.In this paper the additional conversion in their experiments is shown to be explained by the reaction sequence (3)I+H2→HI+H(4)H+HI→H2+I(5)H+I2→HI+I(6)I+HI→I2+H.The rate constants for the rate determining steps (1) and (3) as determined from the equilibrium data are shown to be equal to those determined in systems far from equilibrium. Upper limits can be set on the rates of two para to ortho hydrogen conversion reactions which have previously been suggested to explain the results of Rosenbaum and Hogness: an upper limit of 2.5×10—12 is determined for the collision efficiency of reaction (a) and a lower limit of 47 kcal is determined for the activation energy of (b) (a)H2p+I→H2o+I(b)H2p+HI→H2o+HI.The reactions of hydrogen, both with iodine atoms and with iodine molecules, are shown to be homogeneous in Pyrex vessels at 693°K.
Electron Spin Resonance in an Irradiated Single Crystal of Dimethylglyoxime
Authors: Miyagawa Ichiro , Gordy Walter
Published: January 2005

The paramagnetic resonance of gamma-irradiated single crystals of dimethylglyoxime has been measured at 23 kMc/sec and 9 kMc/sec for various orientations of the crystal in the magnetic field. The resonance pattern was found to have a triplet structure caused by coupling to a single N14 nucleus. Both the nuclear coupling and the spectroscopic splitting factor were found to be anisotropic with the principal values; A1=45±1 gauss, A2=A3=25±1 gauss, g1=2.0026±0.0003, g2=2.0063±0.0003, and g3=2.0095±0.0003. It is concluded that the free radical produced by the irradiation is probably the ionized dimethylglyoxime molecule, CH3–H¨–O–N=C–C=N+–O–H,–CH3with the positive charge and the electron spin density concentrated on one of the nitrogens and in an hybridized sp2 orbital which is approximately in the molecular plane and along the bisector of the C=N–O angle. The s character in the orbital is calculated from the N14 coupling to be 19%.
Vibrational Relaxation Times in Oxygen
Authors: Salkoff Morris , Bauer Ernest
Published: January 2005

The vibrationalrelaxation time of oxygen has been calculated and compared with experiment. Fairly good agreement is obtained with a Morse form for the O2–O2 intermolecular potential.
Growth and Crystal Symmetry of Metal Chelate Salt Crystals
Authors: Van Uitert L. G. , Treuting R. G.
Published: January 2005

A method for growing large single crystals of metal chelate salts such as NaNi triacetylacetonate·p-dioxane and NaNi triacetylacetonate·benzene has been devised. The growth habits of these crystals are described. X-ray studies of three of the NaNi and NaMg salts indicate a diffraction symmetry consistent with space group P3̄c, with two molecules per unit cell. Paramagnetic resonance measurements by M. Peter indicate that the benzene compounds are truly trigonal, while the dioxane compounds are macroscopically trigonal as a result of disordering among unit cells that are individually monoclinic.
Energy Requirements of Mechanical Shear Degradation in Concentrated Polymer Solutions
Authors: Bestul A. B.
Published: January 2005

Molecular weight decrease by mechanical shearing results when solutions of around 10% of polyisobutene having average molecular weights above 500 000 are forced through a capillary at nominal rates of shear above 10 000 sec—1. Comparison of observed plots of shear load vs duration of shearing at fixed rates of shear during this degradation process with the corresponding estimated plots which would be expected to obtain if degradation did not occur provide a means of evaluating the amount of applied shearing energy which is dissipated by the degradation process. The result is several hundred thousand kilocalories per mole of broken bonds, which is several thousand times the bond energy of carbon-carbon bonds. This finding is consistent with the hypothesis that whenever a bond breaks the system loses much of the free energy temporarily stored in bonds and macromolecular chains located in a comparatively large volume surrounding the broken bond, these bonds and chains having been involved in concentrating the required activation energy into the ruptured bond.
NMR Study in Rochelle Salt
Authors: Blinc R. , Prelesnik A.
Published: January 2005

The angular dependence of the proton magnetic resonance absorption of a Rochelle salt single crystal has been measured. The experimental second moments are compared with the theoretical curves, as calculated for the structures proposed so far. Lösche's model was found to reproduce the qualitative form of the angular dependence, whereas the other structures gave no agreement at all.

The occurrence of transitions in the proton magnetic absorption line widths at +24°C and below —20°C demonstrates that the assumption of protonic motion, upon which the dynamic theories of ferroelectricity in Rochelle salt are based, is essentially correct.
Isomeric Effects in Fragmentation by Beta Decay: Monotritiated Propanes and Toluenes
Authors: Wexler S. , Anderson G. R. , Singer L. A.
Published: January 2005

The spectra of positively charged fragments from beta decay of tritium in primary and secondary monotritiated propane and in o-, m-, p-, and α-monotritiated toluene have been determined by mass spectrometric techniques. Although the number of products from decomposition of each molecule is quite large, the mass patterns from the two propanes are fairly similar while the four mass spectra from the isomeric tritiated toluenes are very nearly the same. These results suggest that the influence of the location of the radioactive atom in the molecule on the fragmentation following beta decay is often obscured by secondary processes, such as radiationless transitions, H-atom migration, and other rearrangements of the excited molecular ion before breakup. However, there are significant differences within the two groups of mass spectra. Some of the differences in the propane patterns are consistent with the greater stability of the secondary propyl structure as compared to that of the primary isomer. Energetically plausible decomposition schemes for the tritiated propanes are proposed. The distributions of excitation energies made available to the daughter molecular ions (C3H7He3)+ in the beta transformation of H3 to He3 are estimated.
Molecular Diffusion Studies in Gases at High Temperature. IV. Results and Interpretation of the CO2–O2, CH4–O2, H2–O2, CO–O2, and H2O–O2 Systems
Authors: Walker R. E. , Westenberg A. A.
Published: January 2005

Experimental measurements of the binary diffusion coefficients for the CO2–O2, CH4–O2, H2–O2, CO–O2, and H2O–O2 systems over the nominal temperature range 300–1000° K are reported. The measurements were made by the point source technique. The data have been analyzed in terms of intermolecular potential energies and the rigorous kinetic theory by using the Lennard-Jones (12–6), modified Buckingham (Exp-6), point center of repulsion (inverse power), and the exponential repulsion potential energy functions. It is shown that all four of these functions are capable of fitting the diffusion data with about the same precision (within experimental error). However, the potential energy values themselves which are calculated from these four different fitted models are shown to be widely at variance; especially in the range of interaction corresponding to the lower temperatures. Thus, these results provide an example of the high degree of ambiguity (previously noted by several others) involved in deducing intermolecular potential energies from transport data. The use of such fitted potentials to extrapolate transport data to higher temperatures, on the other hand, is probably a more reliable procedure, and diffusion coefficients for the above five gas pairs (in their unexcited, undissociated states) have been estimated to 3000° K from the potentials based on the 300–1000° K measurements.
Some Effects of Vapors on Electret Behavior
Authors: Beeler J. R. , Stranathan J. D. , Wiseman G. G.
Published: January 2005

The effects of various vapors on the growth and decay of electret polarization have been studied. Particular emphasis was given to the effect of water vapor on polyvinyl acetate. The observed effects appear to arise from two causes: (1) a decrease in the relaxation time and an increase in the magnitude of the volume polarization following infusion of vapor into the dielectric; (2) an increase in the transfer of charge by means of interfacial discharge at the dielectric-electrode gap. The infusion of a polar vapor into a nonpolar solid dielectric gave anomalously large values of volume polarization.

The dielectrics studied were polyvinyl acetate, polyethylene, two acrylic resins, and carnauba wax. The vapors used successfully were water and chlorobenzene; unsuccessful attempts were made to use benzene and isopropyl ether.
Transmission Measurements with Cold Neutrons in Hydrogenous Liquids
Authors: Nasuhoglu R. , Ringo G. R.
Published: January 2005

Measurements have been made of the transmission cross sections of several series of organic liquids for neutrons in the wavelength region of 5–20 A. These cross sections should show effects from weak bonds, since the scattering cross section of hydrogen is quite sensitive to the binding of hydrogen. Results of the measurements and a description of the helical velocity selector used in making them are given. The results give evidence that the motions of the hydrogens of the methyl group are relatively free in liquids.
Infrared Emission Spectra of Gaseous B2O3 and B2O2
Authors: White David , Mann David E. , Walsh Patrick N. , Sommer Armin
Published: January 2005

The infrared emission spectra of gaseous B2O3 and B2O2 in the temperature range 1400–1800°K have been studied in the region 700–4000 cm—1. Distinct bands were found for natural B2O3 at 2040, 1302, and 742 cm—1, and the B10–B11 isotope shifts measured. From the isotope shift data and other considerations the B2O3 molecule has been assigned a V structure having C2v symmetry. A force constant analysis has been made and a frequency assignment is given from which thermal functions have been computed. The calculated force constants are consistent with the high stability of the molecule. Only one emission band of gaseous B2O2, at 1890 cm—1, has been observed. A linear D∞h structure was assumed and a frequency assignment and thermal functions estimated.
Nuclear Magnetic Resonance Studies on Hydration of Cations
Authors: Jackson Jasper A. , Lemons Joe F. , Taube Henry
Published: January 2005

A preliminary study of the O17 NMR spectra of aqueous solutions has shown that it is possible to distinguish solvent water from water in the hydration sphere of certain cations. For certain ions the hydration water of which is sufficiently nonlabile (lifetime for exchange >10—4 sec), it is possible to display the hydration water as a separate NMR peak when the solvent peak is shifted by addition of a paramagnetic ion. A method is suggested for determining the hydration number of such cations by measuring the change in the water available to interact with the paramagnetic ions due to water retained in the hydration sphere of the cations. The enrichment level of the O17 at present available does not permit precise determination of the hydration number, but the results are not incompatible with reasonable values.
Hydrogen Formation in the Radiation Chemistry of Water
Authors: Mahlman H. A.
Published: January 2005

The molecular hydrogen yields in concentrated aqueous sodium nitrate solutions by cobalt-60 gamma-ray irradiation have been observed and correlated with the molecular hydrogen yields observed in dilute solutions. The G(H2) plotted as the cube root of the NaNO3 activity exhibits a sharp break indicative of a change in the mechanism of formation. The predominant process, designated E1, is readily affected by a scavenging solute. A process of lessor magnitude, designated E2, is less susceptible to solute scavenging. The sharp break is interpreted as the cessation of the E1 process. The G(H2) observed in the NaNO3 solutions at 298° K is correlated with the G(H2) observed in ice at 77° K. Of paramount importance is the observation that the hydrogen formed by the E1 process may be eliminated by irradiation of aqueous nitrate solutions at 77° K. The G(D2) data observed in comparable D2O–NaNO3 solutions also exhibit the same mechanisms of formation. The isotope effect on the formation of D2 in D2O is in qualitative agreement with two initial distributions of the H atoms.
Mean Square Amplitudes and Force Constants of Tetrahedral Molecules. I. Carbon Tetrachloride and Germanium Tetrachloride
Authors: Morino Yonezo , Nakamura Yasushi , Iijima Takao
Published: January 2005

The atomic distances and mean square amplitudes of carbon tetrachloride and germanium tetrachloride were measured by the sector-microphotometer method of electron diffraction. The force constants were calculated by use of the mean square amplitudes thus obtained, combined with the normal frequencies. The results indicate that a force field of the Urey-Bradley type is approximately realized in these molecules.
Thermal Conductivity of Condensed Films: Methane
Authors: Clarke John T. , Gorden Ralph
Published: January 2005

A new method of determining the thermal conductivity of condensed films at low temperature has been developed. It is based on determining the surface temperature of a film of known area and thickness by measuring its equilibrium vapor pressure. The thermal conductivity (K) of the film is calculated by measuring the increase in surface temperature as the film thickness is increased when a known heat flux is flowing across the film. For methane at 85°K, K=3.5×10—3 w/cm°K.
Infrared Spectrum and Dipole Moment Function of Lithium Hydride
Authors: James Thomas C. , Norris Wilfred G. , Klemperer William
Published: January 2005

Line intensities in the 0–1 and 1–2 rotation-vibration bands of lithium hydride at 7 μ have been measured. The ratio of the dipole moment to the dipole derivative is ue/(∂u/∂r)re re=1.8±0.3. It is shown that the dipole moment of a diatomic molecule approaches the united atom limit as the third power of the internuclear separation.
Ultraviolet Resonance Spectrum of the Iodine Molecule
Authors: Verma R. D.
Published: January 2005

The ultraviolet resonance spectrum of I2 observed in electric discharges in the region 1830–2370 A has been photographed at high resolution with a 21-ft vacuum grating spectrograph, and a thorough and complete analysis of the data in this region is given. The five doublet resonance series are shown to be excited from five rotational levels of vibrational level v″=0 of the ground state of I2 to three vibrational levels (vn′,vn+0′,vn+4′) of an upper electronic state by a single iodine atomic line 1830.4 A. The rotational constants for the ground state of I2 may be represented: (1)v=0.03734−0.0001208 (v+12)+0.444×10−6(v+12)2−1.839×10−8(v+12)3−0.057×10−10(v+12)4(2)v=1.99×10−9+1.236×10−10(v+12).The ground-state ΔG(v+12) values have been obtained from v″=0 up to the dissociation limit. A precise value of the dissociation energy of I2, has been found to be 12 452.5±1.5 cm—1 as against the previous value of 12439±8 cm—1.

The potential energy curve of X 1Σg+ has been computed by using the Rydberg-Klein-Rees method after modifying its final expressions, right up to the dissociation limit, and certain curious features in the neighbourhood of the dissociation limit are pointed out. The curve follows the van der Waals force law c/r6 between r=4.6 A and r=6.4 A with c=3.7×106. Various possibilities for the nature of the upper electronic state are discussed.
Thermodynamic Properties of Nonstoichiometric Urania-Thoria Solid Solutions
Authors: Aronson S. , Clayton J. C.
Published: January 2005

A solid state electrochemical technique has been used to obtain thermodynamic information on uraniathoria solid solutions of compositions UyTh1−yO2+x with values of y of 0.9 to 0.3 and values of x of 0.02 to 0.16. The electrochemical cells were of the type Fe,FeO | (ZrO2+CaO) | UyTh1−yO2+x, Pt. Measurements were made at temperatures of 1150–1350°K.

Partial molar free energies, entropies, and enthalpies of solution of oxygen in the solid solutions were calculated. The partial molar free energy decreases negatively with increasing thorium content for thorium concentrations greater than 30 atomic percent. The partial molar entropy increases negatively with increasing oxygen content or with increasing thorium content.

The experimental results are discussed in connection with a mechanism of interstitial solution of oxygen ions in the fluorite lattice. A thermodynamic equation for the entropy is developed which gives semiquantitative agreement with the experimental data.
Thermodynamic Properties of Sulfuryl Fluoride from 12°K to Its Boiling Point. Entropy from Molecular and Spectroscopic Data
Authors: Bockhoff F. J. , Petrella R. V. , Pace E. L.
Published: January 2005

The heat capacity of sulfuryl fluoride has been measured from 12 to 218°K. A lambda transition was observed at 65.7°K. The heat of fusion at the triple-point temperature, 137.34°K, was 1074 cal/mole. The heat of vaporization at the normal boiling point, 217.78°K, was 4596 cal/mole. The vapor pressure data are closely represented by the equation log10Pmm=7.8323−1071.235/T−0.01391 log10T.The liquid density from 182 to 204°K is closely represented by the equation d=2.576−0.004044T.The entropy of sulfuryl fluoride gas has been calculated from the calorimetric data and the third law of thermodynamics to be 62.66 eu/mole at 217.78°K. The calculated spectroscopic entropy was 63.24 eu/mole. The discrepancy, 0.58 eu/mole is attributed to randomness in the solid at 0°K.
Interaction of Hydrogen with Tungsten
Authors: Hickmott T. W.
Published: January 2005

Measurements have been made under ultra-high vacuum conditions of the rates and isotherms for the adsorption of hydrogen on tungsten, the rate of desorption of hydrogen from tungsten, and the rate of formation of atomic hydrogen by an incandescent tungsten filament. When hydrogen chemisorbs on tungsten at 77°, the sticking probability is 0.1 and two distinct states of binding, α and β, may be isolated at adsorption pressures as low as 2.5×10—9 mm. Analysis of desorption kinetics of the most tightly bound state, β, shows that hydrogen chemisorbs as atoms since evaporation is second order in adsorbed hydrogen. For nβ< 30×1012 molecules/cm2, vM=(5×10−3)n2exp(−31 000/RT) molecules/cm2-sec. At higher coverages, a decrease in heat of desorption is observed which is due to surface heterogeneity. At equilibrium, the amount adsorbed in the β state obeys a Temkin isotherm between 273° and 373°K; evaporation of hydrogen in the β state occurs down to temperatures as low as 77°K. Isosteric heats agree with heats derived from desorption measurements. The α state, populated before the β state is saturated at 77°K, is proportional to hydrogen pressure and probably consists of molecular hydrogen on top of the primary atomically chemisorbed layer. The rate of evaporation of atomic hydrogen when the filament temperature is raised above 1100°K is vA=(2.2×1013)n exp(−67 000/RT) molecules/cm2-sec. For pressures below 10—7 mm and filament temperatures above 1475°K, the fraction of molecules striking the filament surface that is dissociated is constant and at least 0.05. Values of surface coverage and the rate of formation of atomic hydrogen as a function of filament temperature and hydrogen pressure are derived from experimental data.
On the Effects of Intramolecular van der Waals Forces
Authors: Bartell L. S.
Published: January 2005

Evidence for the existence of strong nonbonded repulsions between atoms bonded to a given atom is cited. It is observed that bond angles in ethylene derivatives and related molecules can be correlated with a simple ``hard sphere'' model in which atomic positions are presumed to be governed by the sizes of spherical atoms packed around a given atom. Estimations of the magnitudes of the nonbonded interactions are presented. These indicate that the shortening of carbon-carbon single bonds in unsaturated hydrocarbons may be principally attributable to the relaxation of nonbonded repulsions across digonal or trigonal bonds as compared with tetrahedral bonds. It is suggested that intramolecular van der Waals forces may be even more important than effects of hybridization and conjugation or hyperconjugation in governing bond angles, bond distances, energies of isomerization and hydrogenation, and bending vibrations of molecules.
Electron Diffraction Study of Monomethyl- and Dimethylphosphine
Authors: Bartell L. S.
Published: January 2005

The structural parameters of gaseous monomethyl- and dimethylphosphine were determined by the sector-microphotometer method of electron diffraction. Center of gravity bond distances and standard errors for the two molecules were, respectively: rCP=1.858±0.003 A and 1.853±0.003 A; rCH=1.094±0.008 A and 1.097±0.007 A; rPH=1.423±0.007 A and 1.445±0.02 A. The angles P–C–H were 109.6±1° and 109.8±0.7°. In dimethylphosphine the angle C–P–C was 99.2±0.6°. The methyl groups were found to be in staggered conformations. The distances and root-mean-square amplitudes of vibration agreed well with the values determined in recent studies of phosphine and trimethylphosphine.
Proton Relaxation Times in Protein Complexes of Paramagnetic Ions
Authors: Wishnia Arnold
Published: January 2005

Proton longitudinal relaxation times in dilute solutions of Fe3+, iron conalbumin (FeCon), and ferrihemoglobin (Hb+), have been measured at 40 and 60 Mc. The static magnetic moment is 5.9 Bohr magnetons for all three species; the ratios of 1/NT1 for Fe3+, Fe Con, and Hb+ are 1:0.72:0.026. For the proteins the relevant correlation time τc in Solomon's expression for the dipolar contribution to T1 is the electron spin relaxation time τS of the paramagnetic ion, which for Fe Con is 3×10—11 sec. τS may contribute to τc in other complexes of Fe3+ and Cr3+. A simple model for Hb+ shows the heme Fe to be 4 A from the surface of the protein.
Chemically Induced Vibrational Excitation: Hydroxyl Radical Emission in the 1–3 Micron Region Produced by the H+O3 Atomic Flame
Authors: Garvin David , Broida H. P. , Kostkowski H. J.
Published: January 2005

A detailed investigation has been performed in the 1- to 3-μ wavelength region on the radiation emitted by the hydroxyl radical from a low-pressure flame of ozonized oxygen and atomized hydrogen. Wavelengths and photon intensities have been obtained for about 300 lines in the OH vibration-rotation bands V—V—ΔV where ΔV=3, V=9 to 5, and for ΔV=2, V=9 to 2. Relative photon band intensities have been determined from the overdetermined set of data by a method of successive approximations using an IBM 650 computer. Dipole moment parameters have been calculated using the above data and Morse oscillator transition probabilities.

Approximate rotational and vibrational Boltzmann distributions exist with an average rotational ``temperature'' of 560°K for the P branches, 460°K for the R and Q branches, and a vibrational ``temperature'' of 9250°K for the ΔV=2 and 3 bands. The absence of radiation from levels V>9 confirms the nonthermal character of the excitation and its dependence on the energetics of the reaction O3+H→OH+O2. Moreover, flux calculations based on the assumption that in this case collisional deactivation transition probabilities are proportional to the radiation probabilities show that there is an appreciable OH production in all levels V≤9 and the main flux of OH through any population level is via ΔV=1 transitions. Possible causes for the large changes in line intensity with pressure and smaller but significant changes with flows or concentrations are discussed.
Rotational Relaxation of Rough Spheres
Authors: Widom B.
Published: January 2005

A theory of rotational relaxation of spherical top molecules in an inert gas is given, under the assumption that the molecules and atoms collide as rough spheres. Some general aspects of relaxation theory are first discussed and a theorem is presented which, under some circumstances, allows the problem to be greatly simplified. The rotational relaxation problem is then solved both for two- and three-dimensional systems. If I is the moment of inertia of the rotating molecule, m the reduced mass of the atom-molecule system, and a the sum of the atomic and molecular radii, and if b=I/ma2, then the most important result of the three-dimensional theory is that Zeff=38(1+b)2/b, where Zeff is the number of collisions suffered by each molecule in a time equal to the relaxation time. This is the analog of a result previously derived by Wang Chang and Uhlenbeck for self-relaxation in the pure molecular gas. Values of Zeff are calculated for a variety of mixtures of spherical top molecules with inert gases.
Proton Magnetic Resonance Study of the Structure of Barium Chloride Dihydrate
Authors: Silvidi A. A. , McGrath J. W.
Published: January 2005

The proton magnetic resonance absorption spectrum of barium chloride dihydrate has been obtained experimentally at room temperature using a Pound-Watkins spectrometer. The results indicate that there are four pairs of p—p directions in the crystal. The p—p distance and direction angles of these four pairs are: 1.58 A, α0=90°, β0=58°, γ0=148°; 1.58 A, α0=90°, β0=58°, γ0=32°; 1.59A, α0=148°, β0=58°, γ0=90°; 1.57 A, α0=32°, β0=58°, γ0=90°. The experimental error for the p—p distance is ±0.02 A and for the direction angles it is ±4°. By using experimental data, x-ray analysis, and the concept of hydrogen bonding the positions of the hydrogen atoms were determined.
Infrared Detection of the Formyl Radical HCO
Authors: Ewing George E. , Thompson Warren E. , Pimentel George C.
Published: January 2005

The photolysis of HI, DI, HBr, and DBr suspended in solid CO at 20°K is described. The formyl radical, HCO or DCO, is produced, as shown by broad absorptions in the visible spectral region (6695, 6352, 6052, 5789, 5548, 5330, 5102 A) which correspond to absorptions of gaseous HCO. Infrared absorptions of HCO (at 1860 and 1091 cm—1) and of DCO (at 1860 and 856 cm—1) provide a basis for discussing the chemical bonding of this free radical, and for calculating its thermodynamic properties.

These experiments, the first infrared detection of a triatomic free radical by the matrix isolation method, depend upon reactivity of the matrix, possibly eliminating difficulties of the cage effect.
Electrical Properties of Organic Solids. I. Kinetics and Mechanism of Conductivity of Metal-Free Phthalocyanine
Authors: Tollin Gordon , Kearns David R. , Calvin Melvin
Published: January 2005

Techniques involving the use of high-intensity, short-duration light pulses have been applied to the study of the kinetics of photoconductivity in films of metal-free phthalocyanine. These experiments, in conjunction with measurements of steady-state photoconductivity, are consistent with the following scheme. The principal route for the formation of charge carriers is via the first excited singlet state, although the lowest triplet state can, to some extent, contribute to charge carrier production. The mobility of the carriers is low and is concentration-dependent, being lower at higher carrier concentration. The decay of the photocurrent is the result of a diffusion-limited bimolecular recombination, with a capture radius of approximately one molecular diameter. The experiments indicate that carriers produced thermally in the dark do not interact with light-produced carriers.
Electrical Properties of Organic Solids. II. Effects of Added Electron Acceptor on Metal-Free Phthalocyanine
Authors: Kearns David R. , Tollin Gordon , Calvin Melvin
Published: January 2005

The addition of ortho-chloranil to the surface of films of metal-free phthalocyanine has been found (a) to increase the dark conductivity of such films by as much as 107, (b) to increase the steady-state photoconductivity by as much as 105, and (c) to result in the formation of unpaired electrons whose concentration decreases reversibly as a result of illumination. These systems exhibit a light-induced polarization, the phthalocyanine layer becoming more positive with respect to the ortho-chloranil layer. Kinetic studies demonstrate that, upon illumination, a single process (time constant=60 sec) results in the increase in conductivity, the decrease in unpaired spins and the increase in polarization. The results are consistent with the following scheme. An electron transfer from phthalocyanine to ortho-chloranil occurs in the dark at room temperature producing holes in the phthalocyanine layer and ortho-chloranil negative ion radicals (high conductivity, ESR signal). Illumination results in the transfer of an electron from an excited phthalocyanine molecule to the ortho-chloranil negative ion producing further phthalocyanine holes and ortho-chloranil double negative ion (increase in conductivity, increase in polarization, decrease in ESR signal). By equating spin concentration with charge carrier concentration (phthalocyanine holes) it is possible to calculate a mobility of 10-4 cm2/v/sec for holes in the phthalocyanine layer. With this value, a quantum yield of unity is calculated for the production of charge carriers in doped phthalocyanine. The experiments indicate a quantum yield of less than 10-1 for undoped phthalocyanine. The over-all results of adding a strong electron acceptor to a film of phthalocyanine are thus to (a) produce charge carriers in the dark, (b) increase the quantum yield for production of charge carriers by light and (c) increase charge carrier lifetime.
Quantum-Mechanical Modified Boltzmann Equation for Degenerate Internal States
Authors: Snider Robert F.
Published: January 2005

A modified quantum-mechanical Boltzmann equation has been derived for the general case in which the molecules have degenerate internal states. This is an equation of the Boltzmann type for a quantity which is simultaneously a Wigner distribution function in molecular phase space, and a density matrix in internal state space. In particular, the nondiagonal terms of this density matrix have been included in the formalism, resulting in the collision term being modified from the usual Boltzmann expression. Thus the collisions are described in terms of combinations of the Lippmann-Schwinger scattering matrix rather than the collision cross section. For nondegenerate states the usual collision term is obtained again.
Forbidden Band Systems in Nitrogen. III. The Y 3Σu—←X 1Σg+ System in Absorption
Authors: Wilkinson P. G.
Published: January 2005

Four bands of the Y 3Σu—←X 1Σg+ system of nitrogen have been observed in absorption in a path of 3.4 meter-atmospheres at 1518 A (0–0), 1484 A (1–0), 1453 A (2–0) and 1423 A (3–0). These bands consist of an unresolved Q branch (QQ, QP, QR), and SR and 0P branches.

From a comparison of the experimental and calculated intensity distribution, it is shown that the upper state is 3Σu— rather than the alternative assignment of 3Δu.

It is further shown that the Y 3Σu— state is identical with the upper state of certain infrared bands recently found in the active nitrogen afterglow. Those bands are thereby identified as Y 3Σu—→B 3Πg. The upper state was designated ``Y'' by Kistiakowsky and Warneck.

The constants of Y 3Σu— as obtained here are: ωe=1517.69 cm—1; ωexe=12.22 cm—1; Be=1.472 cm—1; αe=0.0161 cm—1; T00=65850.6 cm—1; re=1.2788 A.

The transition Y 3Σu—←X 1Σg+ receives intensity from perturbations of Y 3Σu— by 1Σu+ and 1Πu states lying at higher energies.
Lattice Dynamics and Heat Capacity of Indium
Authors: Slutsky L. J. , Livingston Ann
Published: January 2005

The frequency distribution spectrum of the normal modes of vibration for a noncentral force model of indium has been approximated by a root-sampling technique. Interactions between an atom and its first and second-nearest neighbors were considered, the interatomic force constants being evaluated from the room-temperature elastic constants of indium. The calculated specific heat of indium from 4° to 80°K is in fairly good agreement with experiment.
Experimental Oscillator Strength of the Comet-Tail System of CO+
Authors: Bennett R. G. , Dalby E. W.
Published: January 2005

The radiative lifetimes (τv′) of the upper electronic state of the comet-tail bands of CO+ have been measured. There is an appreciable variation (about 50%) of τv′ with v′, the upper electronic state vibrational quantum number. By using an average τ = (2.6)10—6 sec, and an average frequency corresponding to 4200 A an oscillator strength f = (2.2±0.5)10—3 is calculated. The uncertainty arises largely because of the observed lifetime variation with v′.
Anomalous Faraday Dispersion of O2
Authors: Hougen Jon T.
Published: January 2005

The Verdet constant of O2, in contrast to that of other colorless molecules, is not approximately proportional to v2 in the visible, near ultraviolet, and near infrared spectral regions. It is shown below that the inability of early theoretical treatments to explain the observed frequency dependence can be overcome by including in the Hamiltonian for the problem the interaction of the spin magnetic moment of the O2 molecule with the magnetic field of the light wave being propagated through the sample cell. This corresponds to considering magnetic dipole transitions as well as electric dipole transitions in the absorption spectrum. An expression is obtained which fits the oxygen data to 1%.
Calculation of the Heat of Solution of Copper in Germanium from Diffusion Measurements
Authors: Tanenbaum M.
Published: January 2005

The diffusion of substitutional copper in germanium below 700°C has been explained by a dissociation mechanism proposed by Frank and Turnbull. It is shown that this mechanism provides a means for estimating the heat of solution of copper in germanium by measuring the activation energies for substitutional copper diffusion and for self-diffusion in germanium.
Collision of a Gas Atom with a Cold Surface
Authors: Zwanzig Robert W.
Published: January 2005

The collisional transfer of kinetic energy from a gas atom to a cold solid is investigated in a simple model. (The solid is one-dimensional; classical mechanics is used throughout; and simplified interactions are assumed.) In two limiting cases the combined equations of motion of the atom and the lattice are solved exactly. The efficiency of energy transfer obtained from these calculations is much higher than that which is predicted from Lennard-Jones' single phonon approximation.