bluuebunny/crossref_metadata_2025 huggingface dataset:
Light—Scattering and Color Centers in Sodium Cyanide
Authors: Isetti Giovanni , Neubert Theodore J.
Published: January 2005

Single crystals of sodium cyanide show no absorption in the region 10 000–3000 A, but there is a strong absorption which begins at ca 2350 A. In the intermediate region there is a prominent absorption at 2725 A in some crystals. The absorption at 2725 and that which begins at 2350 A are conceded to be due to impurities. For crystals measured (10 000–3200 A) at room temperature the optical density varies with the inverse fourth power of wavelength, thus indicating the presence of light-scattering centers small in extent compared to the wavelength of light. It is suggested that the scattering centers are small regions of rhombohedral phase embedded in the averaged face-centered cubic phase usually observed at room temperature. The possibility that the scattering centers are due to coagulated impurities, however, cannot be excluded. When NaCN is cooled to 0°C the CN— ions become aligned, the structure changes from cubic to orthorhombic and the light-scattering is very much enhanced. At 0°C the optical density varies, in some cases, with the inverse second power of the wavelength and indicates that the scattering centers are large compared with the wavelength of light. In this case the scattering centers are thought to be related to the mosaic block structure of the crystal. Upon x-irradiation, NaCN colors only with difficulty. Absorptions are observed at 5400, 4570, and 3600 A, together with a general increase in absorption at shorter wavelengths. The 4570 A band may be the F band. The coloration is very unstable, bleaching at 30° with a half-time of ca 27 min. At 0°C the coloration is more stable than would have been predicted on the basis of high temperature data, and it is, therefore, suggested that the instability is related to the occasional reorientation of CN— ions which must occur at T>15°C.
Zeeman Effect on the Quadrupole Spectrum of Iodic Acid
Authors: Livingston Ralph , Zeldes Henry
Published: January 2005

The pure quadrupole spectrum of I127 in iodic acid has been observed at several temperatures. At 22°C the z component of the quadrupole coupling is 1126.9 Mc and η, the asymmetry parameter is 0.4505. Zeeman studies on the low frequency transition (±1/2→±3/2) showed an intensity effect that depended on the orientation of the crystal in the rf coil. Extra Zeeman components were present that resulted from a proton interaction, and the study of these essentially located the hydrogen in the crystal lattice. Zeeman studies on the high frequency transition (±3/2→±5/2) showed four components for each type of iodine atom, the two not normally present unless η is large were weak. The splittings of the levels were uniquely assigned and the directions of the principal axes computed.
Thermoelectric Behavior of Solid Particulate Systems. Nickel Oxide
Authors: Parravano G. , Domenicali C. A.
Published: January 2005

Thermoelectric power measurements have been performed on powdered nickel oxide in the temperature range 60–220°C, under different gas atmospheres. These include: oxygen, hydrogen, carbon monoxide, carbon dioxide, nitrous oxide, helium, and water vapor, at different partial pressures. The extent and direction of the observed changes in thermoelectric power of the oxide following gas chemisorption have been related to the extent and nature of the electron transfer process taking place between the different gaseous molecules and the conducting surface. A theoretical analysis of the system is presented. The analysis shows how the ratio between the thickness of the space charge layer at the surface and the ``thickness'' of the thermal gradient affects the thermoelectric power change resulting from chemisorption. Since this ratio depends on the size and size distribution of the solid particles, this effect provides a further parameter which can be used to control and modify the electronic characteristics of semiconducting particulate systems.
Theoretical Investigations on the Light Scattering of Colloidal Spheres. I. The Specific Turbidity
Authors: Heller Wilfried , Pangonis William J.
Published: January 2005

Scattering cross sections, scattering coefficients and specific turbidities are calculated from the Mie equations for α = 0.2(0.2)7.0(1)15 and m = 1.05(0.05)1.30; and, in addition, for α = 22(2)32; 39(1)41 and m = 1.05, for α = 16(1)21 and m = 1.10, for α = 7.2(0.2)15.2 and m = 1.20. Thus, the calculations cover virtually all dispersed systems of ultramicroscopic or small microscopic nonabsorbing spherical particles dispersed in a liquid. The effect of α and m upon these functions is discussed and a few approximating equations are given and tested for the limit of α→∞. The most important features of the Mie theory are briefly discussed and compared with those of alternate approximating theories.
C13-Isotope Effect in the Photolysis of Ethyl Bromide
Authors: Friedman H. L. , Bernstein R. B. , Gunning H. E.
Published: January 2005

The photolysis of ethyl bromide in a tenfold excess of cyclopentane has been studied over the temperature range, 30 to 250°C.

Ethane is the principal volatile product of reaction. The quantum yield of ethane formation has been found to be unity at 30°C. An increase in apparent quantum yield to 1.5 at 250°C was observed. This increase is attributed to the greater absorption of the incident radiation at high temperatures.

The C12 enrichment in the ethane product was 1.0070±0.0008, and invariant in temperature. The isotope fractionation effect is explained on the basis of the higher absorption of C12–C12–Br over C12–C13–Br in the long wavelength region.
Kinetics of Reaction between Hydrogen and Nitrogen Dioxide
Authors: Rosser Willis A. , Wise Henry
Published: January 2005

The gas-phase reaction between hydrogen and nitrogen dioxide has been studied in the temperature range from 600 to 700°K. The stoichiometry of the reaction corresponds closely to H2+NO2=NO+H2O.The rate of disappearance of NO2 is given by −d(NO2)dt=1014(NO2)(H2)1.4e−46 000R/T(NO2)+(NO).The experimental observations are interpreted in terms of a chain mechanism involving hydrogen atoms and hydroxyl radicals as chain carriers.
Intermolecular Potentials for Unlike Interaction on Exp-Six Model
Authors: Srivastava K. P.
Published: January 2005

The potential parameters for the unlike pairs of molecules A–He, A–Xe and Ne–Xe have been determined for the ``exp-six'' model from the temperature dependence of thermal diffusion of these gas mixtures following the method developed earlier by Srivastava and Madan. Unlike the graphical method of Srivastava and Srivastava a purely computational method has been employed here for determining the parameters α12 and ε12. First coupled values of α12 and ε12 were determined by neglecting the temperature variation of the ``g'' factor and using Kihara's first approximation formula. Then the absolute value of the ``g'' factor was calculated at a fixed temperature for various values of α12 and that value of α12 selected which gave the experimental value of the thermal diffusion factor αT. Precise value of ε12 was determined by taking into account the temperature variation of ``g.'' The values of the potential parameters α12, ε12, and (rm)12 thus obtained were found to reproduce satisfactorily the experimental data on thermal diffusion except for very low temperatures where T* is less than 1.5 and the ``exp-six'' law probably does not hold.
Mechanism of Conduction in Li-Substituted Transition Metal Oxides
Authors: Heikes R. R. , Johnston W. D.
Published: January 2005

A study of the effect of Li substitution on the electrical properties of the oxides MnO, CoO, NiO, and CuO has been made. It has been found that (1) the activation energy for conduction increases abruptly near the antiferromagnetic Curie point; (2) as Li is added the activation energy and resistivity initially decrease rapidly and then level off in the neighborhood of 2% substituted Li; (3) this initial decrease becomes progressively greater in going from MnO to CuO in the sequence of the periodic table. A rather complete understanding of these materials can be had by treating the conduction process as a thermally activated diffusion of positive holes which are trapped by the local strain induced by their own polarization field. The magnitude of the activation energy will be related to the work done against elastic forces necessary to reduce the local strain at a positive hole to zero.
Raman Effect in Mixtures of Some Esters with Phenol and Alcohols: Hydrogen Bond Formation
Authors: Puranik P. G.
Published: January 2005

The variations in the frequencies of some of the Raman lines of methyl and ethyl benzoates and ethyl cinnamate, in phenol and methyl alcohol, have been recorded for different concentrations. In all the three cases the C=O frequencies at 1724, 1719, and 1711 cm-1 are lowered as a result of hydrogen bond formation. This reduction is always accompanied by an increase in the frequencies assigned to the C–O link, which is adjacent to the C=O link. Besides these, variations in other frequencies are reported and explained.
Infrared Spectra of the Alkali Halides. I. Lithium Halides
Authors: Klemperer William , Rice Stuart A.
Published: January 2005

The infrared spectra of LiI, LiBr, and LiCl in the gas phase have been measured in the region of the fundamental vibration frequency. The vibrational frequencies are calculated from the observed spectra to be LiI  ωe=501 cm−1LiBr ωe=576 cm−1LiCl ωe=662 cm−1.There is no evidence in the spectra for the existence of appreciable quantities of dimeric molecules, the estimated dimer concentration being thus restricted to less than 15%.

The apparatus used appears suitable for absorption measurements above 2000°C.
Frequency Dependence of Proton Spin Relaxation in Aqueous Solutions of Paramagnetic Ions
Authors: Nolle A. W. , Morgan L. O.
Published: January 2005

Magnetic resonance relaxation times T1 and T2 were measured for protons in aqueous solutions of Cr(H2O)6+++, Mn(H2O)x++, Co(H2O)x++, and Nd(H2O)x++ in the frequency range 2.7 to 28.7 Mc/sec. T1 was observed to decrease with decreasing frequency for the first two ions, but not the last two, while T2 was essentially constant for each ion. The abnormally large values of T1/T2 which have been previously reported appear as a result of the effect at high frequencies. Those observations are interpreted in terms of a theoretical model of the magnetic interaction between ion and proton in which a random thermal process is presumed to occur with a characteristic correlation time, τe, of 10—8 to 10—11 sec.
Rotation-Vibration Spectra of Methyl Amine and Its Deuterium Derivatives
Authors: Gray Allan P. , Lord R. C.
Published: January 2005

Methyl amine, methyl amine-d2, methyl-d3 amine and methyl-d3 amine-d2 of high chemical and isotopic purity have been synthesized and their infrared spectra studied at both prism and grating resolution. The rotation-vibration band centers of methyl amine have been measured with improved accuracy over previous investigations and with the aid of the spectra of the deuterium analogs a vibrational assignment differing in some important respects from those hitherto suggested has been made.

The grating spectra in some cases show irregularities in the rotational fine structure but none which can be associated with effects due to hindered internal rotation. Recent studies in the microwave region have shown that these effects should not be observed within the resolution limits of the grating spectrometers used in this work. However, the first overtone of the torsional frequency in methyl amine, methyl amine-d2 and methyl-d3 amine has been observed in a position consistent with calculations based on a barrier height of 690 cm-1.

The rotational structure of a number of unperturbed vibrational bands has been analyzed in terms of equations applicable to an approximate symmetric top and rotational constants have been obtained in good agreement with values calculated from parameters obtained from microwave investigations.
Theorem of Corresponding States for Polymers
Authors: Prigogine I. , Bellemans A. , Naar-Colin C.
Published: January 2005

A theorem of corresponding states for polymers (r-mers) is derived for condensed states (liquid and solid). This theorem permits to correlate the thermodynamic properties of an homologous series of r-mer molecules. It gives satisfactory results when applied to the n hydrocarbons series.
Short-Range Intermolecular Forces. II. H2–H2 and H2–H
Authors: Mason Edward A. , Hirschfelder Joseph O.
Published: January 2005

The energy of interaction between two hydrogen molecules and between a hydrogen atom and a hydrogen molecule are calculated using a new method1 for approximating the 3- and 4-center integrals. The results are in good agreement with previous calculations of Margenau and with existing experimental data. The multiple exchange and zeroeth order perturbation make our calculations somewhat complicated. Although good results were obtained by de Boer, who neglected these terms, the success of such a procedure depends on a fortuitous cancellation of errors. Following de Boer's procedure for the case of a hydrogen atom-hydrogen molecule interaction, we obtained very poor results.
Effects of Atomic Quadrupole Moments upon the Index of Refraction
Authors: Satten Robert A.
Published: January 2005

The effect of induced atomic quadrupole moments upon the refractive index is investigated using Maxwell's macroscopic field equations. For this purpose a new frequency-dependent parameter δ is introduced which is characteristic of a homogeneous isotropic dielectric and is proportional to what might be called the quadrupolarizability. In order to obtain a dispersion formula a quantum mechanical calculation is made of the induced electric and magnetic dipole and electric quadrupole moments. The results suggest the general form to use for the classical field quantities P, M, Q (electric and magnetic dipole and electric quadrupole moments per unit volume respectively) for the classical theory of crystal optics in a higher approximation.
Infrared Spectra of Ketene and Deuteroketenes
Authors: Arendale William F. , Fletcher William H.
Published: January 2005

The infrared spectrum of di-deuteroketene is reported along with a number of fundamentals which were observed for CHDCO. The spectrum of CH2CO has been re-examined and many new overtones have been assigned. A normal coordinate analysis tends to confirm the assignments through a successful calculation of the observed frequencies for CHDCO.
Dynamic Compression of Liquids from Measurements on Strong Shock Waves
Authors: Walsh John M. , Rice Melvin H.
Published: January 2005

High explosives were used to drive strong shock waves into various liquids, and a moving-image camera was employed to determine velocities associated with the shock waves. The measured velocities are transformed to pressure-compression points by applying the conservation relations. The pressures attained vary among the 15 liquids studied but are typically in the range 50 kilobars to 150 kilobars. For water, more extensive experimentation suffices to determine the Hugoniot curve from 30 kilobars to 450 kilobars. The highest pressure for each of the liquids extends the available data range from static experimentation several fold.

A shock-wave-reflection experimental method is described, the purpose of which is to measure the useful thermodynamic variable (ΔH/ΔV)P at high pressures. Results are given for water.

Qualitative experiments to study the transparency of shocked water, carbon tetrachloride, ethyl alcohol, and benzene are reported.
Partition Function for Internal Rotation in Methanol and Similar Molecular Models
Authors: Halford J. O.
Published: January 2005

Methanol falls outside the range of variables within which the internal rotator partition function and its required derivatives have been dependably calculated by the relatively simple methods of Pitzer and Gwinn. For such cases, Ivash, Li, and Pitzer have proposed a detailed, general formulation of potential extreme accuracy.

It is shown here that their partition function, obtained by integration over functions which are not unique for the model, can have two formally different values. Elimination of an ambiguity from their derivation leads back to an earlier and simpler method developed empirically by Halford, without, however, establishing this method for the general case.

A very simple derivation, which obviously gives answers of readily determined accuracy for a widely distributed set of special cases, is presented. It is shown that the Ivash-Li-Pitzer formulation gives accurate answers under specifiable conditions. It is also deduced that a considerable extension of the Pitzer-Gwinn Tables, at a high level of accuracy, sufficient to cover all likely cases of interest, is possible without serious increase in the detail of calculation.

Such an extension would solve the general case in a practical sense.
Potential Constants of Nitrous Acid
Authors: Palm Ann
Published: January 2005

A normal coordinate treatment was carried out using a general quadratic potential function. Possible sets of force constants were evaluated on the basis of previously observed vibrational bands. The most probable range for the potential constants was established by means of bond order criteria and distributions of potential and kinetic energies among the internal coordinates.
Dielectric Constant of Dipolar Solids
Authors: O'Dwyer J. J.
Published: January 2005

Conflicting formulas for the dielectric constant of a dipolar solid proposed by Frölich and Harris have been critically examined. However, if certain statistical mechanical averages are correctly interpreted, it is shown that Harris' formula reduces to a special case treated by Frölich.
Statistical Mechanics of Liquid-Vapor Equilibrium
Authors: Widom B.
Published: January 2005

The configuration integral of a pure fluid is approximated by considering configurations in which the N particles are distributed in two sub-volumes of the volume V, the potential energy per particle in each sub-volume being taken to be a function, u(vi), of the volume per particle in that region, and interaction between sub-volumes being ignored. When all possible distributions of particles between sub-volumes are considered, and when u(vi) has the form suggested by physical considerations, then the pressure as a function of v=V/N is found to be equal to π(v)=kT/v—u′(v) whenever π(v) is stable, but to be equal to the constant vapor pressure which satisfies the equal-areas criterion whenever π(v) is metastable or unstable. The functions π(v) themselves have the form of a set of isotherms of van der Waals type.
Thermodynamic Formulas for Two-Phase Systems
Authors: Li James C. M.
Published: January 2005

Bridgman's table of thermodynamic formulas or Shaw's table of Jacobians is extended to a two-phase system of one, two, and three components. The present method will include these tables as special cases and can be generalized to any system in a straightforward manner.
Crystal and Molecular Structures of Heterocyclic Compounds. III. α-Phenazine near 80°K
Authors: Hirshfeld F. L. , Schmidt G. M. J.
Published: January 2005

A partial three-dimensional analysis of the crystal structure of α-phenazine at the temperature of boiling nitrogen has yielded, after refinement by a weighted least-squares procedure, carbon and nitrogen coordinates accurate to 0.003 A as well as approximate hydrogen positions. Within the experimental error, the C–C bond lengths are identical with those in anthracene. This agrees with theoretical predictions, for direct molecular-orbital calculations, with allowance for overlap of adjacent atomic orbitals, indicate a maximum difference between corresponding C–C bond lengths in phenazine and anthracene of about 0.01 A, which is of the order of the error in the latter structure. The results imply that neither inductive effects due to chemical substitution nor crystal forces can have any great influence on bond lengths in an alternant hydrocarbon such as anthracene.

The C–H bond lengths average 1.00 A but are not to be compared with direct measurements of the internuclear distance such as are given by electron-diffraction or magnetic-resonance data.

Deviations from molecular symmetry mmm exceed the experimental error only in the direction normal to the mean molecular plane. These displacements from the plane are of the order of 0.01 A and appear to arise from an electrostatic attraction between overlapping atoms in adjacent parallel molecules. Electrostatic interaction, however, is probably not important in determining the type of crystal packing, for a survey of other aromatic structures indicates that the packing type is, in most instances, approximately independent of electrostatic forces.
Electronic Band Structure in Graphite
Authors: Yamazaki Masatoshi
Published: January 2005

The tight-binding approximation is applied to a study of graphite, using Slater atomic orbitals for the carbon atom with nuclear charge 2δ=3.18. The 16×16 determinantal secular equation for the energy is reduced by a group-theoretical treatment of the spatial symmetry at certain special values of the wave vector k. The calculated results are that valence and conduction π bands overlap very slightly to each other at the corner points of the first Brillouin zone—at the wave vector k=2π(½c,⅔a,0)—, σ- and π-valence bands are separated, the σ and π band width is about 16 ev, 1 ev, respectively, and the ionization energy (work function) is about 9 ev.
Interaction between Sulfur Dioxide and Polar Molecules. II. Systems Containing Ethanol, and Benzene or Hydroquinone
Authors: de Maine P. A. D.
Published: January 2005

The near ultraviolet absorption for sulfur dioxide in benzene-ethanol solvent is adequately explained as arising from the superimposed bands for the systems: EtOH+SO2[open phi] lim K1(complex)1;  Benzene+SO2[open phi] lim K2(complex)2,if it is assumed that in passing from nonpolar to polar solvents there is no change in K1, K2, and in the molar extinction coefficients of the two complexes and of the uncombined sulfur dioxide. Extinction coefficients and equilibrium constants for the benzene complex must be obtained from analysis of solutions with high benzene concentration. It was found that the thermodynamic constants of both complexes, calculated from data for the mixed system, are identical with values obtained for the separate systems with carbon tetrachloride.

A similar analysis of the absorption spectra of hydroquinone-sulfur dioxide-ethanol solutions gives a value of 14.0±1.0 kcal per mole for the heat of formation of the hydroquinone-sulfur dioxide complex in ethanol. The heat of decomposition of the solid hydroquinone-sulfur dioxide clathrate compound was found, by Wynne-Jones and Anderson, to be 14.2±0.1 kcal. These results demonstrate the importance of lattices in polar solvents.
Raman Spectrum of Triethylborane
Authors: Blau Edmund J. , Mulligan Barry W.
Published: January 2005

Frequency shifts and polarization data are reported for the Raman spectrum of liquid triethylborane, B(C2H5)3. By comparison with the spectra of trimethylborane and ethane, tentative assignments are made for most of the observed bands.
Infrared Dispersion of Hydrogen Bromide
Authors: Schurin Bertram , Rollefson R.
Published: January 2005

The index of refraction of hydrogen bromide has been measured between 1 and 10 microns. The data have been interpreted to provide values of the electric moment (μ) and the variation of the electric moment with internuclear distance (dμ/dr). The reported values are μ=(0.82±0.04)×10—18 e.s.μ and dμ/dr=(0.48±0.04)×10—10 e.s.μ.
Zeeman Effect on the Quadrupole Spectra of Sodium, Potassium, and Barium Chlorates
Authors: Zeldes Henry , Livingston Ralph
Published: January 2005

All features of the Zeeman pattern of NaClO3 that were examined can be deduced from the crystal symmetry and knowledge of the orientation of the crystal axes in the magnetic field. The crystal axes could be located with respect to the magnet goniometer to within 0.05° by observation of the Zeeman pattern. The line width was found to be 1.2 kc between flexes. A method was devised for orienting KClO3 and Ba(ClO3)2·H2O crystals by attaching a NaClO3 crystal and observing its Zeeman pattern. In KClO3, the field gradient tensor asymmetry parameter η was found to be about 0.006 and the z-principal axis was located and compared with features of the structure. The line, one of the sharpest yet observed, measured 0.29 kc between flexes. In Ba(ClO3)2·H2O, the upper limit for η was found to be 0.05. The z-principal axes were located and compared with features of the crystal structure. The line width was found to be about 3 kc.
Vibrational Spectra of Normal and B10-Labeled Methyl Borate
Authors: Servoss R. R. , Clark H. M.
Published: January 2005

Infrared spectra have been obtained for normal and isotopically labeled methyl borate, B(OCH3)3 and B10(OCH3)3, in the liquid and vapor phases over the NaCl and KBr spectral regions. Raman spectra have been obtained for normal and B10-labeled methyl borate in the liquid phase. The assignment of fundamental frequencies given is consistent with the C3h point group. Normal vibrations for planar molecules of the MX3 type are correlated graphically.
Iodine Complexes in Inert Solvents. II. Complexes of Iodine with Some Aromatic Ethers and Biphenyl in Carbon Tetrachloride
Authors: de Maine P. A. D.
Published: January 2005

Characteristic constants and absorption spectra are given for anisole, p-dimethoxy-benzene, o- and p-methoxy-biphenyl, and biphenyl complexes with iodine, as determined in carbon tetrachloride solution near room temperature. Three absorption maxima are found for the anisole-iodine complex: at 4900 A, 3450 A, and 2950 A. The band near 4900 A is attributed to a modified iodine transition, while the two ultraviolet bands are attributed to the formation of two isomeric charge-transfer complexes. The two non-degenerate anisole donor orbitals, with different ionization potentials, are supposed to correspond to the degenerate pair of benzene e1g molecular orbitals. The ultraviolet absorption spectra found for the other iodine complexes are interpreted similarly.

A method for estimating the two equilibrium constants and the two extinction curves for such complexes, having isomeric forms, is suggested.
Iodine Complexes in Inert Solvents. III. Iodine Complexes with Methanol, Ethanol, or Diethyl Ether in Carbon Tetrachloride
Authors: de Maine P. A. D.
Published: January 2005

Thermodynamic and spectroscopic constants, obtained by a spectrophotometric method, are reported for complexes of methanol, ethanol, and diethyl ether with iodine in carbon tetrachloride. It is shown that the heats of formation of the complexes are nearly identical with values obtained by a nonspectroscopic method.

From the spectroscopic and nonspectroscopic data for solutions of methanol, ethanol, and diethyl ether with iodine or with iodine and carbon tetrachloride, it is concluded that the activity coefficients for the iodine and the alcohols are independent of their concentrations and that in these cases the alcohols do not solvate the complexes even at concentrations of nearly one hundred percent alcohol.

Exact molar extinction coefficients for iodine in n-heptane and in carbon tetrachloride are given in Table I, and related data in Fig. 2.

There is a detailed discussion of errors due to the neglect of temperature effects, underlying bands, and volume changes on mixing the solvents. Evidence in support of ``Liquid Lattice Penetration Complex'' theory, in which it is assumed that the stabilizing forces arise from ``donor-acceptor'' interaction, is also discussed.

It is found that Andrews and Keefer's linear relations between ΔF and ΔH or ΔS, for the aromatic complexes of iodine, do not hold for all iodine complexes.
Remarks on the Theory of Absorption Spectra of Symmetrical Cyanine Dyes and Polyenes
Authors: Olszewski S.
Published: January 2005

The AS FEMO method was applied in order to calculate the absorption maxima in the spectrum of symmetrical cyanine dyes and polyenes. An improvement of the theoretical λmax values for cyanines can be obtained by introducing the ``resonance'' barrier in the FE model. The height of this barrier is determined by the stabilization energies of the cyanine nuclei.
Thermodynamics of the Zr-ZrO2 System : The Dissociation Energies of ZrO and ZrO2
Authors: Chupka W. A. , Berkowitz J. , Inghram Mark G.
Published: January 2005

A mass spectrometric analysis of vapors effusing from a Knudsen cell containing either solid ZrO2 or a mixture of Zr and ZrO2 powders has been employed to determine the vapor pressures, and hence the heats of sublimation of these species. Combined with published thermodynamic data, these results yield 7.8±0.2 ev and 14.5±0.2 ev for the dissociation energies of ZrO and ZrO2, respectively. Previous work is shown to be in error due to the volatility of TaO.
Integrated Rate Equations for Isotopic Exchange in Simple Reversible Reactions
Authors: Alberty Robert A. , Miller Wilmer G.
Published: January 2005

The integrated rate equations are given for various mechanisms by which three substances may be interconverted by first-order reactions. These equations are of special interest in the interpretation of isotopic exchange in the presence of an over-all chemical reaction. When certain rate constants in the mechanism are equal or have the same ratio as the ratio of concentrations of isotopic species in the reaction medium, considerable simplification of the integrated rate equation occurs.
Infrared Spectrum of N15O2 and Force Constants of NO2
Authors: Weston Ralph E.
Published: January 2005

The infrared spectrum of N15O2 has been investigated and the following frequencies were determined: ν1(a1)=1312±3 cm−1,  ν2(a1)=739.7±0.5 cm−1,  ν3(b1)=1578±2 cm−1.From these and the frequencies for N14O2, the following force constants were obtained: fd=10.4±0.5, fα/d2=1.29±0.08, fdd=1.45±0.50, fdα/d=0.098±0.180 (all in millidynes/A).
Phase Transition Temperature of Polonium
Authors: Goode J. M.
Published: January 2005

The phase transition temperatures of polonium have been measured using x-ray diffraction. Transition of α to β polonium occurs at 54°C±1.5°C and the β to α transition occurs at 18°C±1.5°C. The special sample mount used is described.
Elastic and Inelastic Scattering of Low-Velocity He+ Ions in Helium
Authors: Cramer W. H. , Simons J. H.
Published: January 2005

Cross sections have been measured for both elastic and inelastic collisions of He+ ions in the energy range from 4 to 400 ev with helium atoms in the gas phase. Charge exchange was the only inelastic process observed except at the highest energies, where very small cross sections for ionization were obtained. Cross sections for charge exchange decreased slowly with increasing ion energy. The potential functions determined from the elastic scattering data are V=−34.5r−6.88 for r>1.7Aand V=−5.15r−2.90 for r<1.7A.Assuming an equilibrium distance of 1.1A the interaction energy for the formation of the molecular ion He2+ is calculated to be 3.9 ev.
Dissociation Energies of Cu2, Ag2, and Au2
Authors: Schissel Paul
Published: January 2005

A combination of a Knudsen cell and mass spectrometric analysis of the effusing vapor has been used to study the gaseous species in equilibrium with Cu(l), Ag(l), and Au(l). From the observed ratios of monomer to dimer the following dissociation energies have been calculated D00(Cu2)=2.21±0.11 ev,D00(Ag2)=1.78±0.10 ev,D00(Au2)=2.30±0.12 ev.Upper limits for the abundances of the trimers and tetramers are given. Combining the vapor pressure ratios with accepted values for the heats of sublimation of the monomers, the following heats of sublimation for the dimers at 0°K are obtained. L(Cu2)=110±4 kcal,L(Ag2)= 95±4 kcal,L(Au2)=118±5 kcal.
Negative Ion Formation in Hydrogen Chloride by Electron Impact
Authors: Fox R. E.
Published: January 2005

The energy dependence for the formation of Cl— from HCl vapor by dissociative attachment of electrons is studied with a mass spectrometer. Within experimental error the low-energy onset for the capture process occurs at the same energy as that for the maximum capture cross section which is determined to be at 0.66 ev. The ion pair formation process, HCl+e→H++Cl—, is found to have a linear onset at 14.5 ev. The maximum yield of negative ions by this process is found to be only a few percent of that from the low-energy capture process. The energy distribution of the electron beam and the calibration of the energy scale is obtained by comparison with SF6—. It is observed that when a low-energy electron capture process is possible, spurious effects may be obtained at higher electron energies due to low-energy secondary electrons ejected from electrode surfaces by the primary beam.
A Geometric Visualization of Normal-Coordinate Transformations. Application to the Calculation of Bond-Moment Parameters and Force Constants
Authors: Person Willis B. , Crawford Bryce
Published: January 2005

Two methods are given for factoring the normal-coordinate transformation into transformations easier to visualize geometrically. The relations thus obtained have been used in a simple one-dimensional representation of the force constants and bond-moment parameters for CF4 and C2F6. By this means one can easily investigate the existence of force fields which will bring the bond-moment parameters for CF4 and the A2u class of C2F6 into agreement. A further application to the problem of choosing the best force constants for a pair of isotopic molecules is shown for the B3u class of ethylene.
Fluorescence Efficiencies of Organic Compounds
Authors: Furst Milton , Kallmann Hartmut , Brown Felix H.
Published: January 2005

The relative fluorescence efficiencies of a large number of organic compounds of different structures were measured in solution under high-energy and ultraviolet excitations. P/R values of the more efficient solutes under high-energy excitation are given. Where possible at room temperature the fluorescence under high energy was also determined for the compound in solid form. A considerable parallelism is found between the relative fluorescence efficiencies in solution under both modes of excitation. Oxygen effects were measured and found to be greater on the solvent than on the solute, but do not greatly influence the relative efficiencies. Changes in fluorescence produced by substituents which do not considerably alter the absorption spectrum are discussed.
Microwave Spectrum, Dipole Moment, and Structure of Difluorosilane
Authors: Laurie Victor W.
Published: January 2005

The microwave spectra of several isotopic species of difluorosilane, SiH2F2, have been investigated in the region from 12 000 to 38 000 mc. Rotational constants have been determined and the following structural parameters calculated for SiH2F2: rSiH=1.471±0.007 A, rSiF=1.5767±0.001 A, ∠HSiH=112°1′±30′, ∠FSiF=107°56′±6′. An independent determination of the structure of SiD2F2 was also carried out with the following results: rSiD=1.469±0.010 A, rSiF=1.5764±0.001 A, ∠DSiD=113°11′±45′, ∠FSiF=107°57′±10′. Rotational constants for the vibrationally excited state ν4 have been determined for both SiH2F2 and SiD2F2, and certain structural parameters determined. The variation of effective structure upon isotopic substitution is discussed.

Measurements on the Stark effect of the ground vibrational state of SiH2F2 give a value of 1.54±0.02D for the dipole moment. Values for the excited state v4=1 and for SiD2F2 were also measured and agree within the experimental error with the SiH2F2 ground-state value.
Small-Angle X-Ray Scattering from the Low Carbon Paraffins
Authors: Buttrey John W.
Published: January 2005

The small angle x-ray scattering patterns from the four lowest carbon normal paraffins: methane, ethane, propane, and butane have been determined near the critical temperature using a single crystal spectrometer. Monochromatization was obtained with a rocksalt crystal reflecting the Kα lines of copper, and detection was with a Geiger counter.

The data have been analyzed to show a qualitative confirmation of the well-known Zernike-Prins relation between the x-ray intensity scattered at small angles and the isothermal compressibility. A study of a ``particle size'' corresponding to the size of regions of statistical density fluctuation near the critical temperature fails to show a detectable difference in the size of these regions for different thermodynamic conditions of the same hydrocarbon or for different hydrocarbons at roughly equivalent conditions, but indicates an increase in the number of such regions as the transition between liquid and vapor is approached from either the vapor or the liquid.
Vibrational Spectra of Polyethylenes and Related Substances
Authors: Nielsen J. Rud , Woollett A. H.
Published: January 2005

Fairly complete Raman spectra have been obtained of polyethylenes of different crystallinities (Marlex 50, hydrogenated Marlex 50, Marlex 20, and DYNH), Venezuela wax, n-C28H58, n-C36H74, and stearic acid. The infrared spectrum of Marlex 50 has been investigated with a Perkin-Elmer Model 112 spectrometer equipped with LiF, NaCl and CsBr prisms. On the basis of the unit cell and the space group, Vh16, determined by x-ray analysis, the 8 Raman-active unit cell fundamentals of crystalline polyethylene have been assigned as follows: Skeletal deformations 1061 (ag+b1g) and 1131 (b2g+b3g); CH2 rocking 1168 (b1g+ag); CH2 twisting 1295 (b3g+b2g); CH2 wagging 1415 (b2g+b3g); CH2 deformation 1440 (ag+b1g); sym. CH stretching 2848 (ag+b1g); asym. CH stretching 2883 cm—1 (b1g+a1g). In terms of these and 4 of the infrared-active fundamentals assigned by previous workers, it has been possible to assign all but 3 or 4 of the 60 observed infrared bands of Marlex 50. A few bands are ascribed to end groups or to amorphous polyethylene. The infrared-active CH2 wagging and twisting fundamentals (both of species au+b1u) are extremely weak and apparently masked by the corresponding bands of the amorphous phase.
Pure Rotational Absorption Spectra of the Methyl Halides in the Spectral Region 100–600 ų
Authors: Palik E. D. , Rao K. Narahari
Published: January 2005

Rotational absorption lines of the methyl halides CH3Cl, CH3Br, CH3I, CH3F, and CD3F have been measured for the first time in the region 80 to 15 cm—1 (125 to 660 μ). The results obtained are discussed with the aid of the molecular constants of these molecules derived from microwave data.
Distribution of Electrons in the Water Molecule
Authors: Banyard K. E. , March N. H.
Published: January 2005

The electron distribution in H2O is examined using the wave functions of Ellison and Shull (ES) and the density averaged over all orientations about the O nucleus is computed. This is compared with that calculated from the simple central field wave functions used previously by the authors in the interpretation of x-ray scattering results, and there is good agreement between these densities. In addition to the s term in the expansion of the ES density in spherical harmonics, the p term is also exhibited explicitly; it is this which determines the dipole moment of the molecule.

In the second part of the paper a general method is developed for the calculation of the x-ray scattering by a gas of nonspherical molecules. Using this formulation together with the ES density for H2O it is shown that the p term has only a very small effect on the scattering factor. The results using the ES density are in good agreement with those obtained previously and with experiment.
Scattering of Low-Energy H— Ions in Helium, Neon, and Argon
Authors: Bailey T. L. , May C. J. , Muschlitz E. E.
Published: January 2005

Elastic and inelastic cross sections have been measured for the scattering of H— ions in helium, neon, and argon gases, at incident ion energies in the range 5 ev to 350 ev. One term interaction potentials of the form V=—K/rn were calculated from the low-energy elastic cross sections. These potentials were: for H— and He, V=—2.90/r3.01 ev for r=1.30 A to 1.90 A; for H— and Ne, V=—4.17/r2.80 ev for r=1.00 A to 1.78 A; and for H— and A, V=—7.82/r3.40 ev for r=1.23 A to 2.12 A. The observed inelastic cross sections are interpreted as cross sections for electron detachment from H—; they show a similar behavior with ion energy W in the three cases, appearing at W between 0 and 5 ev, rising rapidly to W=40 ev, and then rising very slowly to W=350 ev. Evidence was found for positive ion formation in H— collisions with Ne and A atoms at ion energies above 100 ev.
Theory of Multi-Component Fluid Mixtures. I. Statistical Order-Disorder Analysis in Multi-Component Fluid Mixtures
Authors: Salsburg Zevi W. , Wojtowicz Peter J. , Kirkwood John G.
Published: January 2005

Recent theories of solutions (Prigogine and co-workers; Scott) have been developed without specific reference to a molecular model by the use of a corresponding states procedure which relates the properties of the solution to the properties of one of the pure components. These considerations have been based exclusively upon intuitive postulates which have been formulated by analogy from previous ``cell'' theories of solutions.

The basis for a corresponding states treatment is examined in a rigorous manner by the use of statistical mechanics. A general method is given for reducing the multi-component configurational partition function to a form peculiar to a system of one component. Two types of approximations to the rigorous theory that are amenable to numerical calculations are developed on a strictly mathematical basis, and are used to estimate the magnitudes of the correction terms to a corresponding states analysis.
Perpendicular Bands of Allene
Authors: Rao K. Narahari , Nielsen A. H. , Fletcher W. H.
Published: January 2005

An analysis of the experimental data concerning the four type E fundamental vibration-rotation bands of allene resulted in the following molecular constants for allene: A=5.04 cm−1  or  IA=5.55×10−40 g cm2rC−−H=1.069A  and angle HCH=γ=116.9°.
Microwave Spectrum of Ethyl Bromide
Authors: Wagner Roselin S. , Dailey B. P. , Solimene N.
Published: January 2005

The microwave spectrum of ethyl bromide has been investigated and accurate values for the rotational constants B and C and the asymmetry parameter b have been obtained. For C2H5Br79 B=3804.5 Mc, C=3522.5 Mc, b= —0.00487949 and for C2H5Br81 B=3781.5 Mc, C=3503.0 Mc, and b= —0.00522977. The following model reproduces these constants to within 2 Mc: C–C 1.5495 A, C–H 1.110 A, C–Br 1.9400 A ≰ C –C–H 110°00′, ≰C–C–Br 110°30′. Analysis of the quadrupole hyperfine structure indicates that eqQ along the C–Br bond axis is 537.5 Mc for C2H5Br79 and 450.9 Mc for C2H5Br81. Two transitions have not been able to be fitted by first-order or second-order nondegenerate quadrupole theory. The torsional frequency is estimated to be 202 cm—1 and the barrier height is 2.80 kcal/mole.
Investigations on Cuprous Selenide and Copper Tellurides
Authors: Lorenz Gert , Wagner Carl
Published: January 2005

The activity of copper in cuprous selenide and various phases of the system copper-tellurium as a function of the metal-to-nonmetal ratio has been determined with the help of coulometric titrations. At 400°C the homogeneity range of cuprous selenide extends from a Cu/Se ratio of 1.9975±0.001 to a value lower than 1.86. Homogeneous phases of the system Cu–Te have been found between Cu/Te ratios equal to about 2 to 1.92, 1.43 to 1.39, and 1.32 to 1.30.
Coexistence Curve of the Triethylamine-Water System
Authors: Kohler F. , Rice O. K.
Published: January 2005

The coexistence curve of the system triethylamine-water has been determined near its lower critical point. The observed critical temperature Tc is 18.33°C. There is evidence of a small horizontal portion of the coexistence curve, which extends from 0.559 to 0.657 volume fraction water, or from 0.907 to 0.936 mole fraction water, though the evidence is not absolutely certain. On the other hand, our results exclude the possibility of an anomalous phase transition in the concentration interval from 0.35 to 0.90 mole fraction water where, according to a report by J. E. Mayer, such an anomalous transition may occur. Outside the small horizontal portion the coexistence curve shows the same cubic behavior [(T–Tc)⅓, or better (T–Tc+0.007)⅓, proportional to the difference of the volume fractions of the phases in equilibrium] as do coexistence curves of systems with upper critical points, but is much flatter, the proportionality factor having a smaller absolute value.
Kinetic Theory of Nonspherical Molecules. II
Authors: Curtiss C. F. , Muckenfuss Charles
Published: January 2005

In the kinetic theory of rigid nonspherical molecules, discussed previously, the transport coefficients were expressed in terms of certain multi-dimensional integrals, the brace expressions. In the present discussion these integrals are considered in detail. The integrations over the linear and angular velocities are carried out explicitly and the problem is further reduced to an integral of geometrical parameters over the surfaces of two bodies. The resulting expressions for the transport coefficients apply to any rigid nonspherical convex body in which the center of mass is a center of symmetry. As an example, the final integrations are carried out explicitly for the spherocylindrical model. The shear viscosity, the bulk viscosity, and the thermal conductivity, for this model are presented as functions of two parameters characteristic of the shape and mass distribution of the molecule.
Medium Effects in the Nuclear Magnetic Resonance Spectra of Liquids. III. Aromatics
Authors: Bothner-By Aksel A. , Glick Richard E.
Published: January 2005

The simple relationship between proton resonance line position and sample volume susceptibility applicable to mixtures of simple aliphatic compounds does not hold for mixtures containing an aromatic compound as a component. The departure from regular behavior has been measured in a number of cases, and a possible model explaining the observations is proposed.
Infrared Line and Band Strengths and Dipole Moment Function in HCl and DCl
Authors: Benedict William S. , Herman Robert , Moore Gordon E. , Silverman Shirleigh
Published: January 2005

Strengths of the individual isotopic lines have been measured in the 2–0, 3–0, 2–1, and 3–2 bands of HCl35 and HCl37 and in the 1–0, 2–0, and 3–0 bands of DCl35 and DCl37. The relative line strengths for the 1–0 band of DCl are shown to agree with that expected theoretically including the effect of the interaction of vibration and rotation, but the line strengths in the 2–0 bands agree about equally well with the rigid rotor and with the theoretical expressions including the vibration-rotation interaction. Experimental band strengths and vibrational matrix elements are derived from the measured line strengths for each band. These data are combined with previous results on the HCl 1–0 band to obtain power series expansions for the electric dipole moment function of the hydrogen chloride molecule. It is found that the effective charge is of the same sign as the permanent moment and that the second derivative of the dipole moment with respect to internuclear distance at re is probably of opposite sign. In general, for the same number of terms in the dipole moment expansion it is found that Morse vibrational wave functions give considerably better agreement between observed and calculated matrix elements than do anharmonic oscillator functions retaining terms in the potential energy through the fourth power in the internuclear separation.