bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of Energy Levels for Internal Torsion and Over-All Rotation. II. CH3CHO Type Molecules; Acetaldehyde Spectra
Authors: Kilb R. W. , Lin Chun Chia , Wilson E. B.
Published: January 2005

Methods are described for the calculation of energy levels for the over-all rotation and internal torsion of molecules with a plane of symmetry and one symmetric internal rotor. Typical examples are CH3CHO, CH3SiH2D, and CH3OH. Analysis of the microwave spectra of CH3CHO, CD3CDO, CD3CHO, CH2DCHO, CHD2CHO, C13H3CHO, CH3C13HO, C13H3C13HO, and CH3CHO18 yields V3=1162, 1151, 1143±30 cal, and V6<100 cal, respectively, for the first three isotopic species, where the barrier to internal rotation is V=V3(1—cos3α)/2+V6(1—cos6α)/2. The aldehyde oxygen was found to be opposite one of the methyl hydrogens in the equilibrium orientation of the methyl group. The measured moments of inertia of the nine isotopic species lead to a structure with the parameters

Methyl group: C–H=1.086 A C–D=1.088 H–C–H=108°16′ D–C–D=108°32′ C–C=1.501

Aldehyde: C–H=1.114 C=0=1.216 C–C–H=117°29′ C–C–O=123°55′

The Stark effect gave a dipole moment of 2.69 debyes.
Microwave Spectrum, Structure, and Internal Barrier of Methyl Silane
Authors: Kilb R. W. , Pierce Louis
Published: January 2005

The microwave spectrum of methyl silane has been reinvestigated. Seven symmetric top and ten asymmetric top isotopic species have been studied. These molecules, together with the six symmetric tops studied by Lide and Coles, yield a total of thirty-three rotational constants. A least-squares analysis of these constants gave the following structural parameters:     rSiC=1.8668±0.0005 A,    rCH=1.093±0.005 A,    rSiH=1.485±0.005 A,∠HCH=107∘40′±30′,∠HSiH=108∘15′±30′.Analysis of the spectra of the isotopic species CH2D–SiH2D and CH2D–SiHD2 shows conclusively that methyl silane in its equilibrium configuration has the methyl group staggered with respect to the silyl group.

Certain transitions in the asymmetric top isotopic species, e.g., CH3SiH2D, are split into doublets because of coupling of over-all and internal rotation. These splittings were used to determine the barrier to internal rotation. The form of the potential hindering internal rotation was taken to be V = ½V3(1 — cos3α)+½V6(1 — cos6α), giving the result V3 = 1700±100 cal, V6∼0–150 cal. This is in reasonable agreement with the result of Kivelson's analysis of the J = 0→1 torsional satellites of CH3–SiH3.
Space Group of Tellurium and Selenium
Authors: Asendorf Robert H.
Published: January 2005

A group theoretical analysis is given for the symmetry of the crystal structure and Brillouin zone of tellurium and selenium. This is of particular interest because of the presence in the crystal of a threefold screw axis. Character tables for the group of the wave vector are given for various points of the Brillouin zone. Both the single group and the spin double group are treated. Compatibility relations are given.
Potential Parameters for Krypton
Authors: Madan M. P.
Published: January 2005

Thermal diffusion in krypton has been used in conjunction with thermal conductivity to obtain the intermolecular force parameters of modified Buckingham Exp:6 potential energy function. Experimental data have been reduced and smoothed by using a method described in a previous paper. The accuracy of force parameters have been tested by calculating values of the coefficient of self-diffusion and viscosity at different temperatures and comparing the results with experimental data. Satisfactory agreement was found.
Use of Polar Coordinates for Molecular Wave Functions
Authors: Handler George S. , Arnold James R.
Published: January 2005

Since integrations in polar coordinates are extremely simple, and since the resulting expressions can be extensively tabulated in terms of known functions, it was felt that one might be able to find accurate wave functions for simple molecules using a variational procedure and offsetting the poor initial behavior with a large number of terms. The cases studied were H2, H3+ linear, and H3+ triangular. Convergence was found to be extremely poor, and it is estimated that of the order of fifty terms would be necessary to secure an acceptable result.
Nuclear Relaxation by the Hyperfine Interaction with the Ion Core Spins in Ferromagnetic and Antiferromagnetic Crystals
Authors: Mitchell A. H.
Published: January 2005

The hyperfine interaction of the nucleus with the ion core spins in magnetic crystals provides a relaxation mechanism for the nuclear spins since energy conservation can be obtained by a change in the spin wave energy. In nonconducting magnetic crystals this mechanism may be dominant in the relaxation of the nuclei of the magnetic ions. The relaxation time is calculated for such a nucleus in an antiferromagnetic crystal.
Dielectric Loss of and Defects in Clay Minerals
Authors: Van Keymeulen J. , Dekeyser W.
Published: January 2005

The dielectric behavior of different kaolinites has been examined at frequencies ranging from 100 cps to 20 Mcps and in function of the temperature (20°C—300°C). In the tanδ versus frequency curves from all the studied samples, maxima were observed. These maxima are due to a relaxation phenomenon which take place in the kaolinite lattice. An interpretation of the results is given.
Ionization and Dissociation of Perchlorylfluoride by Electron Impact
Authors: Dibeler Vernon H. , Reese Robert M. , Mann D. E.
Published: January 2005

Relative abundances and appearance potentials are reported for both positive and negative ions observed in the mass spectrum of perchlorylfluoride. Appearance potentials of the atom ions result in a value for ΔHf(ClO3F) of nearly zero within the experimental uncertainty. Bond dissociation energies and ionization potentials of the chloryl radicals are estimated from appearance potentials of the polyatomic ions. The energetics of probable ionization-dissociation processes are compared with observed data.
Vibrational Spectrum of Dimethylphosphine
Authors: Beachell Harold C. , Katlafsky Bernard
Published: January 2005

The infrared spectrum of gaseous dimethylphosphine and the Raman spectrum of the liquid have been obtained. Tentative assignments for the fundamental vibrational frequencies and an interpretation of the observed spectra are given.
Concentration Dependence of Diffusion Coefficient: Analysis of Skewed Diffusion Curve
Authors: Nishijima Yasunori , Oster Gerald
Published: January 2005

Skewed diffusion curves are analytically treated in terms of the Gram-Charlier expansion applied to the Boltzmann equation. The concentration dependence of the diffusion coefficients can be expressed in terms of moments of the diffusion curves.

When the diffusion coefficient is linearly dependent on concentration, the slope is expressed in terms of three parameters of the diffusion curve, namely: (1) the third moment, (2) the height at the initial boundary, and (3) the average diffusion coefficient.
Properties of the Interstitial Compounds of Graphite. IV. Properties of N-Type Compounds
Authors: Dzurus Marceline L. , Hennig Gerhart R.
Published: January 2005

A method has been developed for introducing known quantities of donor impurities into graphite. Some electrical properties of such N-type doped graphite have been measured at various temperatures. Most of the results are in qualitative agreement with theory, and complement previously published results on P-type compounds. It appears that intercrystalline barriers do not influence the electrical property changes during doping, but that the impurities aggregate to some extent and produce channels which differ in properties from the bulk material.
Crystalline Field Selection Rules: The Effect of Vibration-Electronic Interaction
Authors: Satten Robert A.
Published: January 2005

It is pointed out that the selection rules for stationary ions in crystalline electric fields are violated for many transitions in the neodymium bromate and ethylsulfate absorption spectra, making it impossible consistently to assign irreducible representations to crystalline levels. The appearance of spectral lines not obeying the usual crystalline field selection rules is assumed to be due to the interaction of the vibration of the rare earth ion or ion-water complex with its electronic motion about the nucleus. The theory of such an interaction is presented and selection rules derived for D3h, C3v, D3, C3, and C3h local symmetries about the equilibrium position. It is found that the vibration interaction can account for the type of violations seen and with intensities that are probably comparable to some allowed pure electronic transitions.

A satellite structure, which is a consequence of the vibration-electronic interaction, is predicted for all spectral lines except transitions between upper and lower J = ½ or J = 0 levels. Such a structure may be manifested experimentally as a high-temperature ``line width.'' Such satellites of pure electronic transitions should obey the same selection rules and have the same Zeeman effect as the ``parent'' pure electronic transition. The intensity of the individual satellite components of a line does not depend on the strength of the vibration-electronic interaction but only on the Boltzmann factors of their lower state and on the intensity of the parent line.
Structure of Tellurium Oxide Glass
Authors: Brady George W.
Published: January 2005

An x-ray analysis of tellurium oxide glass has been made. This glass is unusual in that it is made up of octahedra which exhibit a close order configuration such that four oxygens are found at a distance of 1.95 A and two others at 2.75 A. This configuration is similar to that found in the crystal. The way in which the octahedra link together is discussed and some observations on the ``edge-opening'' process are discussed. Possible presence of crystallites in the glass is indicated.
Intensities of Rotation Lines in Absorption Bands
Authors: Hanson H. , Nielsen H. H. , Shaffer W. H. , Waggoner J.
Published: January 2005

An alternate method of computing the influence of vibration-rotation interaction on the intensities of lines in the band spectra of molecules from that discussed by Herman and Wallis and by Herman and Rubin is presented. The method consists of transforming the Hamiltonian of the molecule by a contact transformation so that the wave functions remain those for a harmonic oscillator-rotator. The electric moment must then also be transformed by the same contact transformation before the matrix elements of the electric moment are computed. The method is applied to a diatomic molecule and gives the same results as those stated by Herman and Wallis.
Normal Coordinate Analysis of Halogenated Ethylenes. I. General Methods
Authors: Mann D. E. , Shimanouchi T. , Meal J. H. , Fano L.
Published: January 2005

Methods and detailed algebraic expressions are given for the normal-coordinate analysis of ethylenic molecules. In the following paper they are applied to the calculation of potential constants, normal modes, and vibrational frequencies for a series of perhalogenated ethylenes. A force field of the Urey-Bradley type is used for the planar vibrations, and a simple valence-type potential function is applied to the nonplanar motions. The force constants established for the molecules with Vh symmetry are to be used with only linear interpolation and no further adjustment to calculate the fundamental frequencies and modes of all the remaining, less symmetrical ethylenes. For the Vh molecules the vibrational secular equations are set up in the customary GF matrix fashion. The other ethylenes require a somewhat different form which is more readily adapted to calculation by an electronic digital computer. In order that the force constants determined for the Vh molecules be as good as possible a method is given for their adjustment by a least-squaring process.
Time Lag in Nucleation
Authors: Frisch H. L.
Published: January 2005

A definition for the time lag L in the Zeldovich modified Becker-Döring theory of nucleation is introduced which is in accord with the commonly used definition of L in diffusion theory. This L can be obtained exactly without solving for the transient concentration of embryos of the new phase. L is found to be the time required to set up the steady-state distribution of embryos from a given initial distribution by means of the steady-state flux of embryos. The numerical evaluation of L from various initial distributions, for at least vapor-liquid transition, exhibits the importance of the homophase fluctuations in the initial embryo distribution in allowing us to observe the transition within the experimental observation time. The implications of this result for the general theory of phase transitions and for ``memory'' effects in nucleation are discussed.
Infrared Studies of Hydrogen Bonding of Methanol by the Matrix Isolation Technique
Authors: Van Thiel Matthias , Becker Edwin D. , Pimentel George C.
Published: January 2005

The O–H stretching mode of hydrogen bonded methanol has been studied by the matrix isolation technique using solid nitrogen at 20°K as a matrix. The bands are narrow and permit assignment of absorptions at 3660, 3490, 3445, 3290, and 3250 cm—1 to the species, respectively, monomer, dimer, trimer, tetramer, and higher polymers. The results correlate with the room temperature concentration dependence of the H bonded O–H stretching mode of methanol in solution. The dependence of frequency upon polymer size suggests that methanol dimers and trimers have cyclic structures and higher polymers have open (chain) structures. In the cyclic structures, the strain associated with the bent H bond is assumed to account for the low-frequency shift of dimers and trimers compared to higher polymers.
Equations for a Lattice Gas. II. Multio-Cmponent Systems
Authors: Levine Howard B.
Published: January 2005

An expression is developed for P/kT for a multi-component lattice gas with an arbitrary lattice as a multiple power series in a set of kth nearest-neighbor interaction parameters, λa bk, where a and b index the components, with the coefficients functions of the activity set z. By straightforward differentiation, corresponding expressions are obtained for other thermodynamic variables, and also for the probability of finding a pair of particles of specified components on a pair of specified sites. A transformation is outlined which permits the substitution of the number density set ρ for the activity set as independent variables.
Nonresonant Absorption of Symmetric Top Molecules. Shape of the Nonresonant Spectra
Authors: Birnbaum George
Published: January 2005

The nonresonant or relaxation absorption spectrum was mapped out for the symmetric top molecules CH3F, CH3Cl, CH3Br, CH3I, CH3CN, CHF3, CClF3, and (CH3)3N. A cavity method was used to determine the absorption at several frequencies in the range 1200 to 24 000 Mc at pressures up to 2 atmos unless limited by the vapor pressure. Absorption due to the rotational lines was found to be important unless the frequency and pressure were kept sufficiently low. The results for CClF3 and (CH3)3N closely fit the Debye equation and lead to an accurate evaluation of the dipole moment, namely, 0.500×10-18 esu and 0.601×10-18 esu, respectively. The nonresonant spectra of the remaining molecules, which have larger dipole moments, deviate from the Debye shape in a manner that is characteristic of a distribution of line widths.
Study of the A1Π→X1Σ+ Bands of B11F with a Vacuum Echelle Spectrograph
Authors: Onaka Ryumyo
Published: January 2005

The A1Π→X1Σ+ bands of B11F which had been found by Chrétien and Miescher were now studied with the aid of a higher dispersion spectrograph and more accurate molecular constants were obtained, i.e., A1Π:Te=51 157.48 cm−1,ωe=1264.96 cm−1,ωexe=12.53 cm−1,ωeye=−0.242 cm−1,Be=(c)1.4205 cm−1,(d)1.4207 cm−1,αe=0.0165 cm−1,γe=−0.00057 cm−1,D=7×10−6 cm−1,re=1.3047A;X1Σ+:ωe=1402.13 cm−1,ωexe=11.84 cm−1,ωeye=+0.056 cm−1,Be=1.5107 cm−1,αe=0.0165 cm−1,γe=−0.00015 cm−1,D=7×10−6 cm−1,re=1.2652A. Λ-type doubling was observed in the A1Π state, and a brief discussion of the doubling is given in this report.
Burning of a Liquid Droplet. III. Conductive Heat Transfer within the Condensed Phase during Combustion
Authors: Wise Henry , Ablow C. M.
Published: January 2005

The problem of internal heating by conduction during the combustion of a spherical fuel droplet is examined.

The analysis indicates that the temperature pattern within such a system is governed by the dimensionless ratio of burning rate coefficient to thermal diffusivity of the liquid. During combustion the temperature in the center of the droplet may closely approach the surface temperature for liquid fuels commonly employed in propulsion. Such an increase in temperature may lead to thermal degradation and carbon formation observed during the combustion of certain organic compounds.
Vibrational Spectrum of 3,3,3-Trichloropropene-1
Authors: Shull E. R.
Published: January 2005

The Raman spectrum and qualitative depolarizations of the Raman bands of the liquid phase of 3,3,3-trichloropropene-1 and the infrared spectra of the liquid and gas phases have been obtained. A very low Raman frequency, Δν=99 cm—1, attributable to the torsional vibration of the CCl3 group about the C–C bond was observed and a number of the Raman bands were found to be highly depolarized. The observed frequencies consequently have been assigned on the basis of a planar structure (symmetry group C8).
Vibrational Spectrum and Structure of Metal-Cyanide Complexes in the Solid State. II. KAu(CN)2
Authors: Jones Llewellyn H.
Published: January 2005

The infrared spectra of solid KAu(CN)2 and the mono- and di-substituted C13 and N15 species have been observed. The seven fundamental vibrations of the linear, symmetrical Au(CN)2— ion have been assigned at 2160, 452, 2141, 427, 305, 368, and 100 cm—1.

From the observed frequencies of the normal and isotopic species, force constants were calculated for two possible structures: N–C–Au–C–N and C–N–Au–N–C. It is shown that the latter structure gives unreasonably large values for the CN stretching force constant and the CN, AuN interaction constant, and that therefore the cyanides are most likely bound to the gold through the carbon atoms.
Reaction of Diborane with Hg 6(3P1) Atoms
Authors: Hirata T. , Gunning H. E.
Published: January 2005

An investigation has been made of the decomposition of diborane, photosensitized by mercury-6(3P1) atoms under static conditions, at 29.30°C.

The quantum yields of pressure increase and product formation have been found to be independent of substrate pressure in the complete quenching region. For runs of one hour duration at an incident light intensity of 2.5×10—6 einstein/min, the quantum yields are 0.50±0.02 for hydrogen, 0.25±0.02 for tetraborane, 0.02±0.02 pentaborane and 0.070±0.002 for pressure increase. The mean quantum yields of hydrogen and tetraborane formation were found to decrease with increasing duration of exposure during the first half-hour of irradiation. Constant values were reached after 30–45 min of exposure. The ratio of the rates of hydrogen to tetraborane formation was found to maintain a value of two, independent of substrate pressure and duration of exposure, for runs exceeding five minutes in duration. Extensive decomposition was found to lead to solid products.

A mechanism is proposed involving the primary scission of the B–H bond which accounts qualitatively for the observed characteristics of the reaction. The resemblance between ethane and diborane with respect to their behavior toward Hg 6(3P1) atoms is pointed out.
Oxygen Sorption Phenomena on Cadmium Selenide Crystals
Authors: Bube Richard H.
Published: January 2005

A photostimulated, temperature-dependent, reversible sorption of oxygen on cadmium selenide crystals, pretreated to produce donor centers in the surface layers, has been investigated through its effect on the measured dark conductivity. Adsorbed oxygen acts as an acceptor to decrease the surface conductivity at room temperature by at least five orders of magnitude.
Scattering of High Velocity Neutral Particles. X. He–N2; A–N2. The N2–N2 Interaction
Authors: Amdur I. , Mason E. A. , Jordan J. E.
Published: January 2005

Total collision cross sections have been measured for helium atoms with energies between 500 and 2100 ev, and for argon atoms with the same energies, scattered in room temperature nitrogen. The results have been analyzed to obtain the average potential between a helium atom and a nitrogen molecule, 〈V(r)〉Av=1.19×10−10/r7.06 ergs,for r between 1.79 A and 2.29 A, and the average potential between an argon atom and a nitrogen molecule, 〈V(r)〉Av=1.21×10−9/r7.78 ergs,for r between 2.28 A and 2.83 A.

A procedure which takes into account the noncoincidence of the center of mass and the centers of force in the N2 molecule has been developed for expressing these average atom-molecule interactions as functions of the atom-atom potential between the beam particle and either of the nitrogen atoms. These interatomic potentials have been combined with potentials previously determined for He–He and A–A to obtain a hypothetical potential between two nitrogen atoms in different N2 molecules. The following average intermolecular potential for the N2–N2 system has been obtained by averaging such N–N interactions over all mutual orientations of the two N2 molecules: 〈V(r)〉Av=9.54×10−10/r7.27 ergs,for r between 2.43 A and 3.07 A. This N2–N2 potential is consistent with one valid at larger separation distances, which has been derived from measurements on gaseous viscosity at high temperatures.
l-Type Doubling in Three π—π Bands of HCN
Authors: Rank D. H. , Shearer J. N. , Guenther A. H. , Wiggins T. A.
Published: January 2005

l-type doubling constants have been determined for the 0112–0110, 0113–0110, and 0311–0110 bands of HCN. The results, in units of 10—3 cm—1, are: 011201130311q′7.717.5415.4q′′7.517.267.21The accuracy of the constants is ±5% for the 0113 and 0311 bands, and ±1% for the 0112 band. The q′—q″ values obtained for the 0113 and 0112 bands agree within experimental error with the prediction of our empirical equation which relates q to the vibrational quantum numbers.
Raman and Infrared Spectra of CCl3CN
Authors: Edgell Walter F. , Ultee Casper J.
Published: January 2005

The infrared and Raman spectra of CCl3CN have been obtained. The observed frequencies were assigned to the fundamental modes of vibration and their combinations. A normal coordinate treatment of the vibrations has been carried out, using a simple valency force field, supplemented with additional terms representing the interactions between the various nonbonded atoms in the molecule.
Spectra of the Alkali Halides. II. The Infrared Spectra of the Sodium and Potassium Halides, RbCl, and CsCl
Authors: Rice Stuart A. , Klemperer William
Published: January 2005

The infrared spectra of NaCl, NaBr, NaI, KCl, KBr, RbCl, CsCl in the gas phase have been measured in the region of the fundamental vibration frequency. The vibrational frequencies calculated from the observed spectra are: NaCl ωe=366 cm−1,NaBr ωe=302 cm−1,NaI   ωe=258 cm−1,KCl   ωe=281 cm−1,KBr  ωe=213 cm−1,RbCl ωe=228 cm−1,CsCl ωe=209 cm−1.This data, together with previous data on the lithium halides, permits extrapolations to be made to determine the vibrational frequencies of the following halides: KI    ωe=173 cm−1,RbBr ωe=166 cm−1,RbI   ωe=128 cm−1,CsBr ωe=139 cm−1,CsI   ωe=101 cm−1.The classical ionic model for the gaseous alkali halides is found to be in quantitative agreement with experiment. Some aspects of the problem of dimers in the gas phase are discussed.
Intermolecular Forces and the Activation Energy for Viscous Flow in Liquids
Authors: Higgins T. H. S. , Raw C. J. G.
Published: January 2005

The existing theoretical interpretation of the activation energy for viscous flow in terms of the intermolecular potential is discussed in the light of the Born-Green theory. This theory suggests the possibility of an absolute calculation of the activation energy. A simplified treatment affords results of the right order of magnitude.
Rates and Mechanisms of Protolysis of Methylammonium Ion in Aqueous Solution Studied by Proton Magnetic Resonance
Authors: Grunwald Ernest , Loewenstein A. , Meiboom S.
Published: January 2005

The application of the nuclear magnetic resonance technique to the study of fast protolysis reactions of methylammonium ion in water is described. It is shown that reaction rates can be measured quantitatively for half-times in the range, 0.002 to 0.2 sec. Reaction rates were measured as a function of the methylammonium ion concentration and of the hydrogen ion concentration. Detailed information on the reaction mechanism was obtained by correlating the rate constants obtained from the CH3, the NH3+ and the H2O lines of the NMR spectrum. In the pH range employed (between 3 and 5), the exchange rate is very nearly proportional to [CH3NH3+][CH3NH2], the second-order rate constant being 6×108 sec—1M—1 at 19°. Two separate reactions contribute to this rate constant: One of them, which accounts for about 40% of the total rate, is a direct proton transfer from CH3NH3+ to CH3NH2. The other involves also at least one molecule of water, CH3NH2 receiving a proton from the solvation shell of CH3NH3+ while simultaneously, or soon thereafter, a proton is transferred from CH3NH3+ to the solvation shell.
Infrared and Raman Spectra of Phosphorus Pentachloride
Authors: Wilmshurst J. K. , Bernstein H. J.
Published: January 2005

The infrared spectrum of PCl5 in the vapor state and as a solution in CS2 has been obtained. The Raman spectrum of a solution of PCl5 in benzene has been obtained photoelectrically together with depolarization ratios. A complete vibrational assignment has been made on the basis of D3h symmetry, and force constants have been calculated. Thermodynamic functions have been computed from the assigned fundamentals and used to interpret the equilibrium of the reaction PCl3(g)+Cl2(g)=PCl5(g) giving ΔE00=—20 525±160 cal mole—1.
Exchange of Ammonia between Metal-Ammine Cations and Solvent in Liquid Ammonia
Authors: Wiesendanger Hans U. D. , Jones Walter H. , Garner Clifford S.
Published: January 2005

The rates of exchange of NH3 between solvent liquid ammonia and ligand ammonia in five metal-ammine cations have been measured with N15 labeling. Reactants were separated by distilling off the solvent ammonia. Within the exchange times of 0.5, 3, and 11 minutes, respectively, exchange is complete for Ag(NH3)2+, Cu(NH3)4+2, and Ni(NH3)6+2 at concentrations of ca 0.01 f and in the dark at —33.5°C. Based on a single run, exchange with 0.013 f Cr(NH3)6+3 in the dark at 25.0°C exhibited a good McKay plot with a half-time of 1500 minutes, corresponding to a bimolecular rate constant k=1.3×10—6 l·mole—1·sec—1. Exchange with Co(NH3)6+3 was shown to be slow (half-times of the order of several hours at 0.002–0.005 f in the dark at 25.0°C), but reproducible results were not obtained. All complexes were studied as the nitrates. The observed slow exchange for Cr(NH3)6+3 and Co(NH3)6+3 is consistent with their classification as ``inert inner-orbital'' complexes.

Exchange of N15 between NO3— and solvent liquid ammonia, including exchange during the hot NaOH treatment used to distill off the ammonia, is less than 3% at 0.05 f NO3— and 25°C.
Magnetic Susceptibilities of Uranium (IV) Ions in Cubic Crystalline Fields
Authors: Hutchison Clyde A. , Candela George A.
Published: January 2005

The magnetic susceptibility arising from the electrons outside closed shells of U+4 in ditetramethyl-ammonium uranium hexachloride is found to be 19.31×10—4 cm3 mole—1 independent of temperature from room temperature down to the triple point of H2. This result is discussed in terms of a ground state configuration f2 perturbed by the crystalline field. The measurements of others on uranium dioxide are also considered.
Reactions of Alkoxy Radicals. I. Photolysis of Methyl Acetate
Authors: Wijnen M. H. J.
Published: January 2005

The photolysis of methyl acetate has been investigated in the vapor phase over the temperature range 29 to 217°C at varying light intensities and initial pressures. The main primary step is a split of the ester molecule into CH3CO and CH3O radicals.

The following reactions involving methoxy radicals have been established: CH3O+CH3→CH2O+CH4CH3O+CH3→CH3OCH3CH3O+CH3COOCH3→CH3OH+CH2COOCH3.As activation energies for reactions (A) and (C) were obtained EA≤1.5 kcal and EC≃4.5 kcal. No information could be obtained regarding the extent to which reaction (D) occurred. 2 CH3O→CH3OH+CH2O.An activation energy of 10 kcal was obtained for the abstraction of a hydrogen atom from methyl acetate by methyl radicals.
Transfer of Energy in Solid Plastic Solutions
Authors: Avivi P. , Weinreb A.
Published: January 2005

The mechanism of energy transfer from excited solvent molecules to the solute, in plastic phosphors is investigated. Energy transfer efficiencies in styrene and polystyrene solutions are compared. The question whether the phenomenon of energy transfer in plastic systems is the consequence of an intramolecular process in the polymer molecule, is discussed. It is shown that such a process is not an essential condition for high-energy transfer efficiency in plastic solutions. The experimental data furnish strong evidence that energy transfer is the result of intermolecular processes, similar to those occurring in liquid solutions.
Chemical Effects of Hot Atoms
Authors: Monchick Louis , Funabashi Koichi , Magee John L.
Published: January 2005

A model is presented for the study of the chemical effects which result from the passage of energetic atoms through liquid or gaseous media. The particular case of energetic Br atoms in CH3Br is treated in detail. The average rate of energy loss, the range, and the number of C–Br bonds broken in primary events have been calculated. The track structure and the nature of chemical effects are discussed.
Vibrational Spectra of Fluorinated Aromatics. XIII. Benzotrifluoride
Authors: Narasimham N. A. , Nielsen J. Rud , Theimer Rose
Published: January 2005

The infrared absorption spectrum of gaseous benzotrifluoride has been obtained with a 1-m cell and a Perkin-Elmer double-pass spectrometer equipped with NaCl and CsBr prisms. The Raman spectrum of liquid C6H5CF3 has been photographed with a 3-prism glass spectrograph of reciprocal linear dispersion 15 A/mm at 4358 A, and depolarization ratios have been measured for most of the Raman bands. Under the assumptions that the molecule has approximately the symmetry C2v and that phenyl and CF3 vibrations are weakly coupled, all but 3 of the vibrational fundamentals have been assigned and classified as follows: Species a1: 336, 770, 1004, 1028, 1072, 1180, 1457, 1614, 2995, 3022, and 3096 cm—1; Species b1: 199, 618, 902, 1127, 1237, 1362, 1457, 1614, 3022, and 3096 cm—1; Species b2: 139, 485, 695, 770, (800), and 923 cm—1; Species a2: 235, 844, and (ca 950) cm—1; CF3 vibrations: (ca 150), 321, 398, 596 (2 funds.), 657, 1152 (2 funds.), and 1328 cm—1. The spectra have been interpreted in detail.
Tunneling through High Periodic Barriers. II. Application to Nuclear Magnetic Resonance in Solids
Authors: Das T. P.
Published: January 2005

Analytic formulas derived in an earlier paper for the frequency of tunneling through high periodic barriers are here used to derive from nuclear magnetic resonance data in solids the heights of the potential barriers hindering the rotational motion of molecules. The rotations of CH3 groups, NH3+ groups, benzene, NH2 groups and water molecules of crystallization are considered. The use of the barrier heights in correcting for the effect of torsional vibrations of molecules on molecular dimensions obtained from nuclear magnetic resonance data is illustrated. A possible explanation of an isotropic part of the splitting of the proton resonance in Li2SO4·H2O, reported earlier by Pake, is presented. Comments are made on the relative magnitudes of the barrier heights in the different molecules considered.
Photolysis of Water Vapor
Authors: Chen Mei Chio , Taylor H. Austin
Published: January 2005

The photolysis of water vapor has been studied in a flow system at rates up to 5 mole hr—1 and at temperatures up to 540°K under the influence of hydrogen discharge radiation around 1650 A. The products H2, O2 and H2O2 varied in amounts and proportions depending on the geometry of the system. Rapid removal of the products of photolysis from the reaction zone to a liquid N2 trap favored H2O2 production. Resultantly the quantum yield also varied with the geometry of the system, values from 0.03 to 0.3 were obtained. He as a diluent caused a decrease in H2O2 production. Added H2 reduced H2O2 production tenfold, accounted for by its reaction with OH. A mechanism is discussed which is substantiated by a study of the dependence of the reaction rates on light intensity.
Some Overlap Integrals Involving d Orbitals. II
Authors: Roberts Joe L. , Jaffé H. H.
Published: January 2005

Overlap integrals between 3dσ orbitals, between 5dσ orbitals, and between 3dσ and 5dσ orbitals have been computed using an IBM 650 MDDPM. The program is briefly discussed. Analytic relations between dσ—dσ coxial and symbactic overlap integrals are derived.
Isoaffine Reactions
Authors: Hollingsworth C. A. , Potter Robert L.
Published: January 2005

Conditions for the possibility of isoaffine reactions are obtained in terms of the rank of a matrix involving the second-order derivatives of the thermodynamic potentials and in terms of the geometry of the Gibbs free energy surface. Conditions for isoaffine reactions in indifferent states are investigated, and it is shown that isoaffine paths exist for all reactions in the invariant and the monovariant systems at constant temperature and pressure.
Bose-Einstein Gas in a Gravitational Field
Authors: Gersch H. A.
Published: January 2005

Taking account of the quantization of the motion in the direction of the gravitational field alters the density of energy levels for the gas particles. The temperature derivative of the chemical potential is discontinuous at the transition temperature, and there results a jump discontinuity in the specific heat at constant volume.
FE Theory Including an Elastic σ Skeleton. I. Spectra and Bond Lengths in Long Polyenes
Authors: Labhart Heinrich
Published: January 2005

FE theory is refined by introducing the interaction between π electrons and an elastic σ skeleton. It is shown that even for very long polyenes a difference in single and double bond length of the same order of magnitude as in shorter polyenes is to be expected. Bond lengths in the ground and first excited state are calculated, which compare favorably with experimental data deduced by a Franck-Condon analysis of the intensities of vibrational peaks.
Operation of a Center-Fed Continuous-Flow Thermogravitational Column with Unequal Flow Rates in the Two Column Sections. Comparison of Theory and Experiment
Authors: Powers John E. , Wilke C. R.
Published: January 2005

Equations of Jones and Furry are shown to agree well with experimental data over a range of ratios of rectifying section flow to stripping section flow from 0.3 to 5. On the assumption of an effective feed location which yields maximum separation a tentative modification of the Jones-Furry equation is developed which appears preferable at smaller values of the flow rate.
Bulk Density of Separated Lithium Isotopes
Authors: Snyder D. D. , Montgomery D. J.
Published: January 2005

The bulk density of extruded specimens of natural lithium and of enriched isotopes (>99%) was measured by the flotation-equilibrium and by the hydrostatic-balance methods. Upon correction for the slight chemical and isotopic impurities and upon reduction to 20°C, the following results were obtained for the bulk density in g/cm3: lithium-6, 0.460±0.002; lithium-7, 0.537±0.003; lithium-natural, 0.531±0.001. The crystal densities, calculated from the lattice constants determined by x-ray diffraction, are respectively 0.462, 0.539, 0.533, in each case about half a percent higher than the bulk density.
Theory of the Effects of Exchange on the Nuclear Fine Structure in the Paramagnetic Resonance Spectra of Liquids
Authors: Kivelson Daniel
Published: January 2005

A theory of the influence of exchange forces in liquids upon the nuclear hyperfine structure in paramagnetic ``spin resonance'' spectra is presented. Formulas are derived for two limiting cases: for the exchange J much larger than the hyperfine separation A, and for A≪J. It is found that as J increases the hyperfine lines broaden (exchange broadening) and start to shift towards the ``unsplit'' Zeeman frequency. For J≈A, the hyperfine lines have coalesced into a single broad line and for J>A the line narrows (exchange narrowing) about the ``unsplit'' Zeeman frequency. These calculations are discussed in considerable detail. The effect upon the spectrum of electronic-electronic and electronic-nuclear dipolar interactions and the effect of the rapid molecular motions in liquids have also been considered, as well as their interactions with the exchange forces.
Dissociation of CO+ and CO++ Ions by Collision with Neutral Molecules
Authors: Melton C. E. , Wells G. F.
Published: January 2005

The dissociations of CO+ and CO++ ions by ion-molecule collision have been investigated with a mass spectrometer. CO+ dissociates into C+ and O, or C and O+, depending upon the energy of the parent ion. The predominant ion resulting from dissociation of CO++ is C+ suggesting a charge-exchange dissociation reaction. This is supported by the observation that neutral molecules having high ionization potentials such as He and Ne do not produce dissociation in CO++. Energy for the dissociation of CO++ is derived from the electronic energy of the molecular ion rather than from kinetic energy.
Reactions of Nitrogen Atoms. I. Oxygen and Oxides of Nitrogen
Authors: Kistiakowsky G. B. , Volpi G. G.
Published: January 2005

Several reactions of nitrogen atoms have been investigated in a low-pressure flow system, using the principle of a ``stirred reactor'' and a mass spectrometer for the determination of steady-state concentrations.

The elementary processes which have been definitely demonstrated to occur and their rate constants are as follows: N+NO=N2+Ok1≥4×1011 cc mole−1sec−1(1)N=O2=NO+Ok8=2×1012×exp(−6200/RT) cc mole−1sec−1(8)N+NO2=N2O+O10−2k1<k9<10k1(10)O+NO=NO2k3≥1013 cc mole−1sec−1(3)O+NO2=O2+NOk6≥1012 cc mole−1sec−1.(6)Unless indicated, the rate constants are at room temperature.

The rate constant of nitrogen atom reaction with nitrous oxide is less than 108 cc mole—1 sec—1 at 280°; that of oxygen atoms is less than 2×108 at room temperature, neither having been observed to occur.

Nitrogen atoms probably react with nitrogen dioxide also by a different mechanism than (10), yielding 2NO and/or N2+O2, at a rate which is competitive with (10). Nitrous oxide is probably formed also by another mechanism, which does not involve nitrogen atoms and may well be the reaction of vibrationally excited nitric oxide with nitrogen dioxide.

The accommodation coefficient of glass walls, treated with phosphoric acid, for the recombination of oxygen atoms, has been determined as 10—4 in one reactor and is larger than this in another.
Rate Constants at Low Concentrations. III. Atomic Oxygen Reactions in the Photolysis of Nitrogen Dioxide at 3660 A
Authors: Ford Hadley W. , Endow Noboru
Published: January 2005

Quantum yields have been obtained for the disappearance of nitrogen dioxide in photolysis at 3660 A and at concentrations below 4×10—7 mole per liter in nitrogen at one atmosphere pressure. The effects of small amounts of added nitric oxide and oxygen on the quantum yields were also observed. From these data and an assumed mechanism it was possible to calculate the rates of reaction of atomic oxygen with nitric oxide and nitrogen dioxide relative to the rate of reaction of atomic oxygen with molecular oxygen. These relative rates were converted to absolute rates using Benson and Axworthy's rate constant for the O+O2 reaction.
Crystallographic and Magnetochemical Studies on ABO3 Group Compounds of Lanthanon and Manganese Oxides
Authors: Vickery R. C. , Klann Ardys
Published: January 2005

Perovskite-structured compounds have been prepared containing manganese oxide with praseodymium, neodymium, and dysprosium oxides. X-ray crystallographic data have been obtained for these compounds, and unit cell edge values of 3.82, 3.80, and 3.70 A are found for PrMnO3, NdMnO3, and DyMnO3, respectively. Magnetic susceptibilities of these compounds have been measured down to liquid-air temperatures and gram susceptibilities found to range from 40–158% above those indicated by additive values for the component oxides, highest increments being found in praseodymium systems. Susceptibility curves follow the Curie-Weiss law without deviation, and Weiss constants of 115, 112, and 62 have been found for the praseodymium, neodymium, and dysprosium compounds, respectively.
Mechanical Resonance Dispersion in Crystalline Polymers at Audio-Frequencies
Authors: Fitzgerald Edwin R.
Published: January 2005

Measurements of the complex shear compliance (J*=J′—iJ″) of crystalline polymers (polytetrafluorethylene, linear polyethylene, and polyvinyl stearate) at closely spaced frequencies in the audio-frequency range have resulted in the discovery of multiple frequency dispersions of the resonance type. Values of the loss compliance (J″) are found to have sharply defined maxima in the range from 100 to 5000 cps; values of the storage compliance (J′) rise to a maximum and then drop to a minimum as a narrow (50 to 100 cps wide) dispersion region is traversed in the direction of increasing frequency. The results indicate the presence of a dispersion mechanism different from those leading to the usual relaxation dispersions observed in connection with the mechanical properties of polymers. The magnitudes of the mechanical loss maxima and the frequencies at which the effect is observed depend on the static stress history and state of the sample material as well as temperature. Similar results obtained for pure polycrystalline metals (lead, indium, and aluminum) lead to speculation that stress-induced motions of dislocations or other imperfections in the crystalline structure may be important in producing this type of dispersion. At present, however, there is no satisfactory explanation for these phenomena.
Intensity of the Symmetry-Forbidden Electronic Absorption Band of Formaldehyde
Authors: Pople J. A. , Sidman J. W.
Published: January 2005

The weak bands of formaldehyde extending from λ3500 A to λ2300 A are normally assigned to a 1A2←1A1, n→π transition (C2ν symmetry) which is forbidden by electronic selection rules. The present paper gives a quantitative theoretical discussion of the total intensity of these bands in each of the three directions of polarization. Using approximate wave functions for the various electronic states involved, the theory shows that the intensity of the perpendicular bands can be accounted for by vibrationally-induced mixing of excited electronic states. The calculated total intensity due to this mechanism is f=3×10—4. It is predicted that most of this intensity is produced by the out-of-plane bending vibration and is consequently polarized perpendicular to the C–O axis and in the molecular plane (B1 polarized). The contribution due to in-plane vibrations (CH2 wagging and antisymmetric C–H stretch), which would be polarized perpendicular to the molecular plane (B2 polarized), is predicted to be much weaker. This is in agreement with experiment.

The weak parallel bands that have been observed cannot be interpreted in terms of vibrational-electronic interaction. It is suggested that these derive their intensity by borrowing, induced by rotation around the C–O axis, from the strong 1A1←1A1, π→π transition. A quantitative theory of this effect gives f∼10—6 for the total oscillator strength of the parallel bands. Several predictions which might be tested experimentally are made on the basis of this hypothesis.
Drude-Model Calculation of Dispersion Forces. II. The Linear Lattice
Authors: Bade W. L. , Kirkwood John G.
Published: January 2005

The London-van der Waals cohesive energy of a linear lattice is calculated in the dipole-dipole approximation, including all orders of perturbation. This result is obtained by applying the Born-von Kármán method to the electronic motions, using a model which represents each molecule as an isotropic harmonic dipole-oscillator. The dispersion interaction energy of the lattice is expanded in powers of the parameter α/a3 (where α is the molecular polarizability and a the nearest neighbor distance), and is computed up to the eighth order. For values of α/a3 appropriate to actual molecular crystals, the main contribution to the energy comes from the second order. Among the higher order terms, the third order is always important, but for α/a3≥0.06, contributes less than one-half of the total correction to the second-order energy.
Role of Crystal Edges in Evaporation
Authors: Sears Gerald W.
Published: January 2005

Direct experimental evidence is presented to show that crystal edges may serve as a source of steps for evaporation. Thus even a perfect crystal can evaporate at low undersaturations.
Reinvestigation of the Molecular Structure of 1,3,5,7-Cyclooctatetraene by Electron Diffraction
Authors: Bastiansen O. , Hedberg Lise , Hedberg Kenneth
Published: January 2005

The molecular structure of 1,3,5,7-cyclooctatetraene has been studied by a sector-microphotometer technique using data extending to very much larger scattering angles than were obtained in earlier investigations. An application of the method of least squares to sector-microphotometer data in electron diffraction worked out by one of us (KH) has led in three refinement stages to unusually precise values for the parameters. The following are the more interesting parameter values with standard errors. It should be noted these results do not include a possible error of up to 0.2% in the scale of the molecule because of uncertainties in the electron wavelength, nor do they include the effect of correlations among the observations on the standard errors, which we estimate might increase the standard errors by as much as the factor 2½. Molecular symmetry D2d,C=C=1.334±0.001 A,C–C=1.462±0.001 A,C–H=1.090±0.005 A,∠C=C–C=126.46∘±0.23∘,∠C=C–H=118.3∘±5.9∘,aC=C(=〈δl2〉C=C/2)=(103±7)×10−5,aC–C=(147±10)×10−5,aC1···C3=(256±13)×10−5, aC1···C4=(530±100)×10−5, aC–H=(327±36)×10−5, aC2···H=(520±110)×10−5,aC3···H=(640±180)×10−5.
Investigations of the Detonation Properties of Condensed Explosives with Equations of State Based on Intermolecular Potentials. I. RDX with Fixed Product Composition
Authors: Fickett W. , Wood W. W. , Salsburg Z. W.
Published: January 2005

An attempt is made to determine an average pair potential of intermolecular force for the mixture of product gases of the condensed explosive RDX (cyclotrimethylenetrinitramine) from measurements of the detonation velocity. The principal approximations are that the products of detonation consist of CO, H2O, and N2 in equimolar proportions and that the equation of state for this mixture can be calculated from theories of the free-volume type with the use of an average intermolecular potential. It was found that the average intermolecular potential was fairly well determined at distances somewhat less than the crossover distance.

This result was almost independent of the choice of equation of state, although the calculated values of detonation temperature and pressure were not.
Electronic Energy of LiH and BeH
Authors: Miller James , Friedman R. H. , Hurst R. P. , Matsen F. A.
Published: January 2005

Valence bond calculations for LiH and BeH+ have been completed. All twenty structures which can be written for 1s, 2s, and 2pσ on the metal atom and 1s on hydrogen are considered. It was found that only six structures are of importance and that promotion of inner shell 1s electrons adds nothing to the description. The results for LiH agree well with those obtained by previous workers.