bluuebunny/crossref_metadata_2025 huggingface dataset:
Helium Diffusion through Glass
Authors: Altemose V. O.
Published: April 2005

Helium permeation rates have been determined through 20 different glasses using a mass spectrometer to measure the gas flow rates directly. The temperature range investigated was 25°–500°C. Values of diffusion constants and solubilities have been computed for 10 of these glasses. The permeation rate has been related to glass composition. It is felt that a better correlation exists between log permeation rate and mole percent of glass network former (SiO2, B2O3, and P2O5) content than exists between log permeation and weight percent of network former as used by previous workers in this field.
Analysis of Photojunctions Formed by Diffusing Copper into Insulating Cadmium Sulfide Crystals
Authors: Bockemuehl Robert R. , Kauppila James E. , Eddy David S.
Published: April 2005

A study of the observed photovoltaic, photorectification, and field effect modulation properties of junctions formed by diffusing copper into photoconductive, dark-insulating CdS crystals shows that two potential barriers are produced, one at the surface, the other in the crystal bulk. A transition from a double space charge dipole to a single separated dipole occurs at a reverse bias of less than 1 v. A corresponding transition from a primary to a secondary photocurrent process results. Values for the drift mobility of holes ranging from 10−5–10−2 cm2/v-sec were derived from field effect measurements and found to be proportional to illumination intensity at the infrared quenching wavelengths.
Electroluminescence atp-nJunctions in Gallium Phosphide
Authors: Gershenzon M. , Mikulyak R. M.
Published: April 2005

Both diffused and alloyed junctions were prepared from single crystals of GaP cut from ingots grown near the melting point, as well as from crystals grown at lower temperatures. The diodes were characterized by their current-voltage relationship and their capacity at reverse bias. Anomalies in both the forward and the reverse currents, an excess capacity, and a hysteresis effect are attributed to the presence of deep centers in the depletion layer, particularly in the alloyed structures. A nearly compensated layer was found at the junction of the diffused diodes. The spectra, bias dependences, decay times, and efficiences of the electro-luminescence emitted at these junctions at both forward and reverse bias were studied and correlated with the diode models. At reverse bias, radiative intraband relaxation was due to carriers excited during avalanche breakdown (diffused diodes), by internal field emission (alloyed diodes), and from carriers thermally generated within the depletion layer (all diodes). At forward bias, only the diffused junctions exhibited light emission and this was of two types: (1) a band-to-band recombination with phonon cooperation, whose recombination kinetics depended on whether or not the process occurred within the depletion layer, and (2) recombination through a deep level which may be associated perhaps with a vacancy.
Propagation in Periodic Electron Beams
Authors: Mueller W. M.
Published: April 2005

A small-signal analysis of smooth electron beams with periodic variations in their dc parameters reveals the existence of infinite sets of space harmonics of the fast and slow space-charge waves. For a finite beam coupling between the space-charge waves and field waves exists at an infinite number of frequencies. The periodicity of a beam has a very small effect on the space-charge wave propagation constants. Velocity-jump, rippled-stream, and rippled-wall amplification are shown to result from coupling between fast and slow space-charge waves of adjacent harmonics. The periodicity of an electron beam will have negligible effect on most conventional traveling-wave devices. Although the frequency dependence of the amplitudes of the beam harmonics may introduce difficulties in some devices, this dependency may also be made use of in a variety of ways. Beam harmonics make millimeter-wave interactions possible in smooth circuits, but practical devices at these frequencies will probably be limited to those employing positional periodicity of the beam.
Piezoelectricity of Quartz for Finite Strain
Authors: Machlup S. , Christopher M. E.
Published: April 2005

In order to obtain an estimate of the maximum piezoelectric polarization possible for alpha quartz, the principal piezoelectric coefficient is calculated on the basis of a hard-sphere, rigid-ion model. The result, obtained by purely geometrical reasoning (including an ad hoc geometrical constraint), fits the measured value of e11 with an ``effective ionic charge'' of one-sixth the free ionic charge. Extension of the calculation to finite compressive strain yields a maximum polarization of 3.4 μcoul/cm2 at a 34% strain. (Compare with e11=16.7 μcoul/cm2 per unit strain.) For higher strains the polarization drops off rapidly, but the model becomes inconsistent for strains greater than 43%. A test for more general validity of the model, by obtaining directly the ratio of the two independent piezoelectric coefficients, e14/e11, yields seven times the measured ratio.
Some Theorems Concerning the Mutual Polarizabilities of Atoms and Bonds in Conjugated Molecules
Authors: Jaffé H. H.
Published: April 2005

Atom bond polarizabilities πr, st in alternant hydrocarbons (AH's) vanish identically. The calculation of πr, st in ions derived from AH's by addition or removal of one or more electrons (AHI's) is discussed, and the conditions under which they vanish are examined. Mutual atom polarizabilities πr, s and mutual bond polarizabilities πrs, tu in AHI's are related to the corresponding quantities in the parent AH's. The dependence of all the polarizabilities on Coulomb and resonance integrals is examined.
Spectroscopic Studies of Rotational Isomerism in Fluorinated Ethanes. II. 1,2-Dibromo-1,1,2,2-Tetrafluoroethane
Authors: Kagarise R. E. , Daasch L. W.
Published: April 2005

The Raman spectrum of liquid CF2Br–CF2Br has been investigated, and the observed frequency shifts (Δν cm—1), relative intensities and depolarization factors are presented. The infrared absorption spectrum of the liquid in the 2—34μ region, and of the solid and vapor in the 2—22μ region have also been studied.

On the basis of observations of the Raman spectrum of the liquid and the infrared spectrum of the vapor, liquid, and solid it is concluded that CF2Br–CF2Br exists as two isomeric species. Of these, the trans-form (C2H) is the more stable, while the gauche-(C2) is probably the higher energy form. The value of ΔH° for the reaction trans-(C2H) ← gauche-(C2) was found to be 925±50 calories/mole in the liquid and 945±50 calories/mole in the vapor state.
Calculation of Energy Levels for Internal Torsion and Over-All Rotation. I. CH3BF2 Type Molecules
Authors: Wilson E. Bright , Lin Chun Chia , Lide David R.
Published: April 2005

Methods are described for calculating the energy levels for the over-all rotation and internal torsion of molecules consisting of a rigid symmetrical top attached to a rigid asymmetrical framework in such a way that the symmetry axis of the top coincides with a principal axis of the molecule. Probable examples are nitromethane and CH3BF2. Matrix perturbation methods are employed to obtain finite rotational secular equations valid in each of the cases: low barrier, high barrier, low asymmetry. These secular equations are modifications of the ordinary Wang equation for the rigid asymmetric rotor and can usually be solved by the continued fraction method. The symmetry groups applicable to this problem are also discussed.
Experimental Determination of Rotational Temperatures and Concentrations of OH in Flames from Emission Spectra
Authors: Penner S. S. , Björnerud E. K.
Published: April 2005

In order to illustate the use of two-path experiments for correcting for self-absorption, experimental studies to determine the rotational ``temperatures'' and concentrations of OH in flames burning at atmospheric pressure have been carried out. For mixtures of H2, C2H2, and O2, as well as for C2H2–O2 flames diluted with A, ``anomalous'' rotational ``temperatures'' were observed under conditions in which strong self-absorption was clearly indicated by the intensity ratios for the double-path to the single-path experiments. Unequivocal quantitative estimates of rotational temperatures and of OH concentrations cannot be carried out, even on the assumption that the emitting system is isothermal and in equilibrium. However, by using the results of theoretical studies on two-path experiments carried out by one of us, it is possible to obtain reasonable upper limits for the temperatures and lower limits for the OH-concentrations, based on an assumed Doppler contour for the line-shape and utilizing Oldenberg's estimates for the f values of representative spectral lines. Our experimental studies lead to reasonable rotational temperatures at the tip of luminous cones for mixtures of H2, C2H2, and O2 and for C2H2–O2 flames diluted with up to 60 percent argon. These observations do not disprove the reality of rotational temperature anomalies in the inner cones of flames. Significant improvement of experimental procedure, and quantitative interpretation of results along the lines used by us, requires additional basic studies with emphasis on the measurement of spectral line-shape and absolute intensities.
Ultrasonic Dispersion in Methyl Alcohol Vapor
Authors: Ener Cavid , Busala A. , Hubbard J. C.
Published: April 2005

Ultrasonic velocities have been measured at temperatures of 32°C in the vapor of methyl alcohol, at pressures from 1.12 to 16 cm Hg, and at frequencies from 0.2 to 2.0 Mc sec—1. A systematic variation with pressure of several percent in the measured values of velocity at the lower frequencies is attributed in large part to dimerization of the vapor. Previously determined constants in state equations for methanol have not been found adequate to reconcile the values of velocity at the higher pressures, but empirical values not far from those found by Weltner and Pitzer are satisfactory. There remains evidence of a thermal dispersion of velocity, attributed to internal rotation with a relaxation frequency of 100 Mc sec—1 atmos—1, corresponding to a relaxation time of 2.27×10—9 sec.
Photoconductivity and Crystal Imperfections in Cadmium Sulfide Crystals. Part II. Determination of Characteristic Photoconductivity Quantities
Authors: Bube Richard H.
Published: April 2005

From measurements of photoconductivity on low conductivity ``pure'' cadmium sulfide single crystals, and on high conductivity cadmium sulfide crystals with chloride impurity, values for the following characteristic photoconductivity quantities have been obtained: (1) concentration of levels in the forbidden gap, (2) energy distribution of such levels, (3) attempt-to-escape frequency for electrons in traps, (4) capture cross section of traps, (5) capture cross section of recombination centers, (6) mobility for electron charge carriers, and (7) binding energy for the electron held in an orbit around the chloride ion in conducting crystals.
Hydrogen Overvoltage and Electrode Material. A Theoretical Analysis
Authors: Rüetschi Paul , Delahay Paul
Published: April 2005

It is shown on a theoretical basis that the overvoltage for hydrogen evolution on various metals and for otherwise identical conditions of electrolysis is essentially a linear function of the heat of adsorption of atomic hydrogen on the electrode. This relationship is deduced on the assumptions that the effect of the backward electrode reaction—the oxidation of hydrogen—can be neglected, and that the current is controlled by the discharge of hydrogen ions. This is the case for overvoltages larger than 0.1—0.15 volt. The relationship between overvoltage and heat of adsorption is tested for metals for which reliable overvoltage data are available, that is for Ag, Be, Cd, Cr, Cu, Fe, Ga, Hg, In, Ni, Pb, Tl. The argument is based on a kinetic equation for hydrogen overvoltage and on the use of potential energy curves for the initial and final states. These curves are determined from spectroscopic data. Heats of adsorption of atomic hydrogen are calculated by assuming the additivity of the M–M and H–H bond energies. Calculated heats of adsorption are listed for 25 metals. It is also shown that there is no correlation between hydrogen overvoltage for various metals and the electronic work function of these metals.
Some Complexities in the Reaction System : H2+I2=2HI
Authors: Benson Sidney W. , Srinivasan R.
Published: April 2005

Existing thermal and kinetic data are sufficient to show that in the reaction H2+I2=2HI, free radical processes may contribute significantly to the overall rate at temperatures above 600 K. This provides a reasonable explanation for some of the anomalies observed in this system and indicates that further kinetic study of the system is desirable.
Electrochemical Polarization in Isopropyl Ether
Authors: Rider John A.
Published: April 2005

Measurements have been made of the polarization effects in electrical conduction through isopropyl ether. This liquid was chosen because its conductivity is intermediate between that of dielectric liquids and water. Correlation of experimental results in this range with the Jaffé theory had not heretofore been checked. The present results provide a bridge across the gap which formerly existed in polarization measurements between conductivities of 10—6 ohm—1 cm—1 and 10—18 ohm—1 cm—1.

Observations were made of the time dependence of current following the application of various voltages to the electrodes of a cell containing the liquid.

Measurements in the present range broaden the pattern of agreement of the Jaffé theory with experiment. Such agreement now extends from semiconductors and aqueous solutions to dielectric liquids. In all cases good quantitative agreement is obtained provided part of the conductance is attributed to carriers of considerably lower mobility than the ordinary conductivity carriers.
Low-Temperature Absorption Spectra of Benzene, Toluene, and Para-Xylene in the Farther Ultraviolet Region
Authors: Potts W. J.
Published: April 2005

The absorption spectra of the 2100 A and 1850 A transitions of benzene, toluene, and para-xylene show sharp structure at low temperature. The sharp structure of the 1850 A transition shows that it is a π—π type transition, and not a dissociation band. Its correct assignment is 1A1g ← 1E1u, with analogous assignments in toluene and para-xylene. The 2100 A transitions of these molecules can be assigned to 1A1g ← 1B1u and its analogs, while the 2600 A transitions are assigned to 1A1g ← 1B2u. Evidence presented indicates that there is no 1A1g ← 1E2g transition in this region of the spectrum.
Single Ion Free Energies and Entropies of Aqueous Ions
Authors: Latimer Wendell M.
Published: April 2005

Single ion free energies of hydration were assigned by Latimer, Pitzer, and Slansky by choosing a set of ion radii which made both negative and positive ions fall on the theoretical Born curve in a plot of ΔF against 1/r′. The r′ values were the crystal ion radii plus 0.1 A for negative ions and plus 0.85 A for positive ions. It is now shown that this assignment of single ion free energies is consistent with the single ion entropies of hydration if S̄H+ is —2.1 (the Eastman value). The ΔS values are proportional to Z/r′ and the tentative suggestion is made that it is the temperature coefficient of r′ which leads to the Z/r′ function. It is proposed that the ΔF values be used to calculate a consistent set of radii of aqueous ions which will take into account coordination numbers and polarization.
The System Pyridine-Pyrrole and the Association of Pyrrole
Authors: Vinogradov Serge N. , Linnell Robert H.
Published: April 2005

Pyridine and pyrrole react together to form a 1:1 complex as shown by infrared, heat of reaction, viscosity, refractive index, and density data. The heat of formation of this complex is 3.8 kcal/mole. Pyrrole itself is associated, but, like the simple alcohols, cannot be represented by a simple equilibrium. The heat of dilution of pyrrole in CCl4 is 1.4 kcal/mole at infinite dilution.
The Normal Coordinates of N-Dimethylaminodiborane
Authors: Breene R. G.
Published: April 2005

The multiple origin method has been utilized for the selection of initial coordinates for the description of the normal vibrations of N-dimethylaminodiborane. Symmetry considerations were then used in order to obtain symmetry coordinates from these MOM coordinates, and, under the assumption of a diagonal potential function, these coordinates were assigned to vibrational frequencies which have been recently reported by Mann. The valence force constants for the methyl-N-methyl framework vibrations were then calculated and the results compared with similar constants obtained from the dimethylamine molecule.
Anomalous Dielectric Dispersion in Polar Macromolecular Solutions
Authors: Hammerle W. G. , Kirkwood J. G.
Published: April 2005

The Kirkwood and Fuoss theory of dielectric dispersion in polymer solutions is recalculated by including the Oseen hydrodynamic interactions in the polymer's diffusion tensor. The theoretical results agree with experiment where comparison is possible. The recalculation gives root-mean-square molecular dimensions consistent with values calculated from viscosity and light scattering.
Dielectric Properties of Methanol and Methanol-1-Propanol Solutions
Authors: Denney Donald J. , Cole Robert H.
Published: April 2005

Measurements of dispersion in the solutions show that at all concentrations the principal dispersion is a simple relaxation process, while the higher frequency behavior gives evidence of overlapping dispersions. As in other alcohols, the temperature dependences of relaxation times differ markedly from simple rate laws, especially for temperatures below 200°K. The significance of the results in relation to reorientation of hydroxyl and alkyl groups and intermolecular hydrogen bonds is discussed. Difficulties in measurements on solid methanol are described and their possible origins examined.
Thermodynamic Properties of Ideal Gaseous Methanol
Authors: Ivash E. V. , Li James C. M. , Pitzer Kenneth S.
Published: April 2005

New calculations are presented for the thermodynamic properties of methanol which are based upon the most recent spectroscopic data. The molecular constants related to the internal rotation are now well established. The vibrational assignment is discussed and additional arguments are presented for the correctness of the selections of Herzberg and Plyler. The method of statistical calculation is essentially that of Halford, but avoids an approximation. Complete thermodynamic functions are tabulated for the range 100 to 1000°K. Agreement with experimental thermodynamic data is satisfactory.
Absorption Spectra of Luminescent Thallous Chloride Solutions
Authors: Scott Allen B. , Hu Kuo—Hao
Published: April 2005

The absorption spectra of solutions of KCl, made luminescent by the addition of TlCl, have been analyzed with the assistance of dissociation constants for TlCl and TlCl2— obtained from solubility measurements. Absorptivities for each of the absorbing species have been found at several wavelengths. Spectra of solutions having a wide variety of KCl and TlCl concentrations were calculated from the absorptivities and dissociation constants; these agree quite well with the observed spectra except at high Cl— concentration, where the disagreement is ascribed to the formation of more highly coordinated complexes. Decrease of dielectric constant of the solvent shifts the absorption band in the direction to be expected from an increase in the stability of molecular TlCl and the complex ions.
Transformation of Adsorbed Water on Solid Surfaces and its Dielectric Losses and Conductivities
Authors: Kurosaki Shigehiko , Saitō Shōgo , Satō Genju
Published: April 2005

The adsorption isotherm of water vapor on nonalkali glass cloth was obtained at 25°C, and its dielectric power factor was measured also in the frequency range of 80 kc/sec∼11 mc/sec.

The power factor of glass cloth and surface dc conductivities of nonalkali glass, soda glass, fused silica, Teflon, and polymethylmethacrylate plates increased rapidly to maximum peaks, when they were exposed to water vapor, and then gradually decreased to certain constant values.

These phenomena may be interpreted as physical picture of phase changes in the adsorbed water phase from the amorphous state to the crystalline state, as well as the deposit films of evaporated metals on solid surfaces. But the surface conductivity of polycapramide increases as the moisture content increases with time, suggesting a rapid absorption of water molecules into the solid. An analysis of this process of phase change of adsorbed water is outlined.
Refined Procedure for Analysis of Electron Diffraction Data and Its Application to CCl4
Authors: Bartell L. S. , Brockway L. O. , Schwendeman R. H.
Published: April 2005

A refined procedure for obtaining the structure of free molecules from electron diffraction data is described which compensates for the interference arising from non-nuclear scattering. The procedure is applied to CCl4 using somewhat more extensive rotating sector data than has hitherto been published for this molecule. Estimates are made for the first time in electron diffraction results of the effect of anharmonicity of vibration on the measurement of internuclear distance and of the effect of the failure of the Born approximation on the measurement of amplitudes of vibration. A method of estimating the reliability of the results is described.
Flame Structure Studies. III. Gas Sampling in a Low-Pressure Propane-Air Flame
Authors: Friedman Raymond , Cyphers Joseph A.
Published: April 2005

A previous investigation of this series showed that the temperature in a very lean, low-pressure propaneair flame continues rising for more than a centimeter downstream from the zone of blue luminosity. This suggested a two-stage combustion process: (I) the hydrocarbon oxidizes rapidly and luminously to carbon monoxide; (II) the carbon monoxide oxidizes more slowly to carbon dioxide. The current gas-sampling study has provided support for this hypothesis. Both water-cooled and uncooled probes have been used to obtain gas samples from the region of the flame just beyond the luminous zone. Tests were made to insure that reaction-quenching in the probe was effective and that flame disturbance was minimized. Gas analyses were performed both mass-spectrometrically and by a vacuum-freezing technique. Most of the samples were taken from a flame burning at 46 mm Hg abs pressure, with a mass air-propane ratio of 30. Substantial proportions of CO, and about 15 as much H2, were found as much as a centimeter downstream from the luminous zone, with probes of much less than a millimeter diam. The CO concentration decayed exponentially with distance; a kinetic analysis yielded a decay constant of 231 reciprocal seconds. (The flame temperature was 1605°K.) The H2/CO ratio was considerably less than that corresponding to water-gas equilibrium in the flame. No traces of hydrocarbons were found beyond the luminous zone.
Phenomenological Relations of Electro-Osmosis in Paper Electrochromatography
Authors: Wood Scott E.
Published: April 2005

Phenomenological equations, based on the thermodynamics of irreversible processes have been developed for the electro-osmosis as observed in paper electrochromatography when the electrodes are placed directly on or in the paper.
Absorption Bands of N2O Near 4.5μ
Authors: Lakshmi K. , Shaw J. H.
Published: April 2005

The absorption bands of N2O near 4.5μ have been remeasured. In addition to the intense lines of the v3 and v3+v2—v2 bands, many new weak lines have also been observed and their frequencies determined. Although no band assignments could be made for these weaker lines, the molecular constants obtained from the other two bands agree well with the values reported by Thompson and Williams.
Liquid Metals. II. X-Ray Diffraction by Liquid Mercury and the Distance of Closest Atomic Approach
Authors: Lukesh Joseph S. , Howland William H. , Epstein Leo F. , Powers Marion D.
Published: April 2005

The distance of closest approach in mercury determined from vapor viscosity data, 3.25 A, differs considerably from the value found by x-ray and neutron diffraction studies on liquid Hg, 3.00 A. This x-ray value has been confirmed using a balanced filter-spectrometer technique and all the essential features of the intensity versus Bragg angle curve observed in previous studies have been verified except the low angle peak reported by Campbell and Hildebrand. The discrepancy between the two r0 values is attributed to the probable persistence of the asymmetrical structure known to exist in the solid into the liquid phase, and its subsequent vanishing in the vapor state.
Steady-State Burning of a Liquid Droplet. I. Monopropellant Flame
Authors: Lorell Jack , Wise Henry
Published: April 2005

The flame equations corresponding to the steady-state combustion of a liquid droplet are presented and adapted to the case of a monopropellant system with chemical reaction diffused throughout the gas phase. The theoretical analysis is applied to the case of a liquid hydrazine monopropellant flame.
Effects of Oxygen on PbS Films
Authors: Minden Henry T.
Published: April 2005

The effect of oxygen on the conductivity of vacuum evaporated PbS films has been experimentally investigated. When outgassed these films are n-type semiconductors. If they are exposed to oxygen at temperatures below about 200°C, the conductivity decreases with increasing pressure and then increases again. The thermoelectric power changes from negative to positive, but less than 10—3 moleO2/molePbS is sorbed by the film.

Above 200°C the conductivity merely decreases when oxygen is admitted, and the thermoelectric power becomes small. The film gradually absorbs all the oxygen in the vacuum system and evolves a good deal of SO2. When the reaction is complete, the conductivity returns to its initial value, and the thermoelectric power is once again negative. The film can repeatedly absorb large amounts of oxygen without there being any permanent change in electrical properties.

It is concluded that these films are composed of two layers. Next to the substrate there is a conducting layer that chemisorbs oxygen but does not react with it. The chemisorbed oxygen acceptors are responsible for the observed changes in conductivity. The upper layer of the film is nonconducting and reacts to completion with oxygen, possibly forming PbSO3:PbO, and evolving SO2.
π-Electronic Structure of the HCN Molecule
Authors: Iguchi Kaoru
Published: April 2005

The HCN molecule is treated as a system of four π electrons moving in a suitable potential field. Its lower excited states are calculated, using both the molecular orbital method with configuration interaction and the Heitler-London method including ionic-homopolar resonance.

Slater atomic orbitals with effective charges 2δ=3.18 for the C atom and 3.85 for the N atom are employed.

The calculated energy levels with the 1Σ+ ground state as zero are 3.53 ev (3Σ+), 5.60 ev (1Σ—), 7.71 ev (3Δ), etc. The effect of configuration interaction is remarkable, amounting to several electron volts, and ionic terms have almost the same weight as homopolar terms.
Infrared and Raman Spectra of Fluorinated Ethylenes. VI. Fluorotrichloroethylene
Authors: Nielsen J. Rud , Gullikson C. W. , Woollett A. H.
Published: April 2005

The infrared spectrum of gaseous CCl2:CClF has been observed from 2 to 22μ with NaCl and KBr prisms. The Raman spectrum of the liquid has been photographed with a three-prism glass spectrograph of linear dispersion 15 A/mm at 4358 A, and the depolarization ratios of the stronger Raman bands have been measured. All but one of the fundamental vibration frequencies have been assigned, and the spectra have been interpreted in detail.
Dispersion and Absorption of Sound in Imperfect Gases in General Chemical Equilibrium and Its Application to Chemical Kinetics
Authors: Tabuchi Daisaku
Published: April 2005

Previously, it was shown that there occur the dispersion and the absorption of sound owing to the chemical reaction in the gas in general chemical equilibrium such as aA+bB+···⇄qQ+rR+···. As the velocity and the absorption coefficient of sound are affected predominantly by the imperfection of the gas over other factors, the case of imperfect gases is considered. The velocity and the absorption coefficient are derived from the complex velocity of sound, and the characteristic of the dispersion and absorption curves are examined. The velocity and the absorption coefficient of sound are formulated in terms of the pressure, the density, the virial coefficients, the equilibrium constant, namely, the composition, the reaction heat at a constant volume, the molar heat at a constant volume, and the rate constant of the chemical reaction. By measuring the velocity and the absorption coefficient of sound, it is possible to calculate the rate constant of the chemical reaction and the reaction heat. As special cases, the formulas for the perfect gas and for a mixture of imperfect gases in which no chemical reactions occur, are derived. As an example of the calculation, the case of the dissociation equilibrium A⇄B+B was treated.
Equation of State of Gases by Shock Wave Measurements. I. Experimental Method and the Hugoniot of Argon
Authors: Christian Russell H. , Yarger Frederick L.
Published: April 2005

An experimental method is described for the simultaneous measurement of the velocity of a plane shock through a gas and the associated particle velocity. Shocks are generated by a plate driven by a high-explosive system. The velocities are recorded by a high-speed rotating-mirror smear camera with a precision of about ±½%. Data are presented defining the Hugoniot of argon between 200 and 1100 Los Alamos atmospheres. These data are compared with the theoretically predicted Hugoniot.
The System Ozone-Oxygen
Authors: Jenkins A. C. , DiPaolo F. S. , Birdsall C. M.
Published: April 2005

At temperatures below —180°C liquid ozone and liquid oxygen are not miscible in all proportions. Two liquid phases occur over a definite range in composition which depends upon the temperature. The solubility diagram at saturation pressures has been determined experimentally by measuring vapor pressure versus composition isotherms at —183.0°C, —185.7°C, and —195.6°C. The upper or oxygen-rich liquid phase has been analyzed at —181.9°C, —182.9°C, —186.0°C, and —195.6°C. The critical solution temperature is —179.9°C±0.5°C. A liquid-vapor equilibrium diagram at one atmosphere total pressure has also been determined experimentally.
Molecular Theory of Light Scattering
Authors: Fixman Marshall
Published: April 2005

The Einstein-Smoluchowski phenomenological theory of light scattering is shown to agree with the molecular theory of light scattering for a one component system of isotropic scattering molecules.
On the Fermi Resonance and Isotope Effect in the Infrared Spectrum of Carbon Tetrachloride
Authors: Tuomikoski P.
Published: April 2005

The influence of intermolecular (solvent) interactions on the Fermi resonance in a number of CCl4 infrared absorptions has been examined: it is discussed together with the incidence of isotopic frequencies.
On the Semiempirical Treatment of the Pi Electrons of Some Halogen Substituted Benzene
Authors: Knipe R. H.
Published: April 2005

The pi moments of some halogen-substituted benzenes have been estimated from measured moments and compared to the predictions of a semiempirical molecular orbital theory of the pi electrons. Using parameters suggested by a perturbation treatment of these molecules, the results of two previous semiempirical molecular orbital treatments considering different molecular properties are compared with each other and with the estimated pi moments. The agreement is in general found to be good.
Determination of the Velocity of Sound in Hydrazine-Water Mixtures by Means of the Debye-Sears Ultrasonic Light Diffraction Phenomenon
Authors: Kretschmar George G.
Published: April 2005

The velocity of sound has been determined at 4 megacycles for a large number of different concentrations of hydrazine in water from 8 to 99 weight percent of hydrazine. The velocities were determined from the diffraction of a monochromatic light beam which was projected through a glass-sided cell containing the liquid in which standing waves were set up by an oscillating quartz crystal. The light source was a sodium arc and the frequency of the ultrasonic wave train was determined with a precision frequency meter. The diffraction angles were measured on a Gaertner spectrometer, reading to one second of arc. The data can be represented by the equation V=1497.40+745.460H+382.353H2−556.3361H3,where V is the velocity of sound in the hydrazine-water mixture at 25°C and H is the fractional weight of hydrazine.
Activation Cross Sections of Y90 and Pr142
Authors: Smith R. R. , Reeder S. D.
Published: April 2005

The irradiation of Y89 and Pr141 under a sufficiently high thermal neutron flux produces small amounts of Y91 and Pr143 by secondary neutron capture. A measurement of the second-order activities, although completely unobservable at the end of the irradiation, may be made after the shorter lived first-order activities have disappeared. From relative measurements of the first- and second-order activities induced in Y89 and Pr141 values for the activation cross sections of Y90 and Pr142 have been established. For Pr142 a value of σact = 18±3 barns was found; for Y90 a value of 6.5 barns was established as an effective upper limit.
Gas Adsorption on Heterogeneous Surfaces
Authors: Hepler Loren G.
Published: April 2005

The mathematical treatment of the adsorption of gas on nonuniform surfaces has been investigated with respect to the proper limits for the integration of the isotherm equation. The physical significance of these limits is discussed. Equations that relate the distribution of energy sites over the surface and the heat of adsorption are derived.
Configuration of Polymer Molecules with Excluded Volume
Authors: Krigbaum W. R.
Published: April 2005

The displacement distribution for a polymer molecule with excluded volume is derived by rejecting the unacceptable configurations available to random-flight chains. The fraction of those configurations corresponding to a displacement length L which are acceptable is calculated through use of a model which considers the chain to be composed of a sequence of identical subchains. Interactions between the elements of a given subchain, and between these and elements of the various possible clusters of adjacent subchains, are summed to obtain the total interference for all elements of the chain. The average interference encountered by the elements of one subchain is calculated therefrom. The resulting displacement distribution is considerably sharper than the corresponding Gaussian distribution for positive values of the excluded volume, but somewhat more extended than the corresponding Gaussian for negative excluded volumes. When the present treatment is compared with that of Flory, the former predicts smaller values for the mean-square displacement length, 〈L2〉, at both the low and the high ends of the molecular weight scale, and a more marked dependence of 〈L2〉 upon the thermodynamic interactions as embodied in the factor (½—χ12). Comparison with experiment confirms these predictions, and indicates the present treatment to be a significant improvement over that proposed earlier by Flory.
Absolute Thermal Decomposition Rates of Solids. Part II. The Vacuum Sublimation Rate of Molecular Crystals
Authors: Schultz Robert D. , Dekker Albert O.
Published: April 2005

The linear rates of sublimation of rhombic benzene and rhombic sulfur have been calculated by use of absolute reaction rate theory in reasonable agreement with rates derived from published experimental data. Required mean torsional oscillation and translational oscillation frequencies for the molecules in the crystal lattice were obtained by an analysis of the available heat capacity and Raman spectral data. A detailed comparison of this treatment with Penner's treatment of the sublimation process is included.
Infrared Spectrum and Molecular Constants of CD4
Authors: Kaylor Hoyt M. , Nielsen Alvin H.
Published: April 2005

The infrared spectrum of CD4 has been examined from 900 cm—1 to 8500 cm—1. A total of twenty-eight bands were observed, including four originally measured by Nielsen and Nielsen under somewhat lower resolving power. Twenty-three bands were attributed to CD4, two to CD3H, two to CH4, and one was unassigned. With the aid of the band centers of the corresponding fundamentals in CH4, the following vibrational constants of CD4 were obtained: the normal frequencies ω̃1=2143.2, ω̃2=1109.4, ω̃3=2336.8, ω̃4 1026.8 cm−1; the harmonic potential energy constants k1=2.093×105, k2=2.841×105, k3=8.463×105, k4=2.790×105, k5=1.329×105 dynes/cm. From the rotational analysis of nine bands, the B values of the upper states for these modes of vibration were found as well as the following rotational constants: the vibration-rotation interaction constants α1=—0.017, α2=—0.015, α3=0.014, α4=0.017 cm—1; B0=2.591 cm—1; Be=2.614 cm—1; Ie=10.70×10—40 g-cm2; rC—D=1.095×10—8 cm; rD—D=1.788×10—8 cm; and the moduli of the internal angular momentum ζ3=0.145, ζ4=0.355.
Vibrational Intensities in Halogenated Methanes. I. Methylene Chloride
Authors: Straley Joseph W.
Published: April 2005

The absolute infrared absorption intensities of four fundamental bands in CH2Cl2 have been measured in the vapor state. The intensities that have been observed are A6 (CH stretching)=48.0×1010 cycles/sec at NTPA7 (CH rocking)=13.0×100 cycles/sec at NTPA8 (CCl stretching)=1420.0×1010 cycles/sec at NTPA9 (CCl rocking)=375.0×1010 cycles/sec at NTP.These data indicate that the bond moments and bond derivatives are μCH=+0.45×10−18 esuμCCl=−0.95×10−18esu∂μCH/∂rCH=+0.3×10−10 esu or −0.2×10−10 esu∂μCCl/∂rCCl=+3.7×10−10 esu.It was not possible to resolve the ambiguity in signs that lead to the alternate values of ∂μCH/∂rCH.
Ionization of Strong Electrolytes. IV. Nuclear Magnetic Resonance and Dissociation of Trifluoroacetic Acid
Authors: Hood G. C. , Redlich O. , Reilly C. A.
Published: April 2005

Proton and fluorine magnetic resonance of trifluoroacetic acid in water reflects the influence of electrolytic dissociation below a mole fraction 0.5 and of hydration above 0.5. The dissociation constant is estimated to be 1.8.
Heat Capacity of Erbium from 15 to 320°K
Authors: Skochdopole R. E. , Griffel Maurice , Spedding F. H.
Published: April 2005

The heat capacity of erbium has been measured over the range 15 to 320°K and the thermodynamic functions have been calculated. Three maxima have been observed which occur at 19.9°K, 53.5°K, and 84°K. The two at the lower temperatures show a dependence on the thermal history of the sample, and this dependence was investigated. A correlation of the various contributions to the entropy at room temperature has been made and extended to the other rare earth metals.
Study of Electrokinetic Effects Using Sinusoidal Pressure and Voltage
Authors: Cooke Claude E.
Published: April 2005

The electrokinetic effects streaming potential, streaming current, and electro-osmotic pressure were studied by applying and measuring sinusoidal variations of hydrodynamic pressure and electrical voltage. Phenomenological relations between the effects were investigated, and an improved experimental method for measuring the electrokinetic coefficients, hence the zeta potential, was used. Saxen's law was verified within 6% at frequencies of 20, 100, and 200 cycles per second. The systems studied were restricted to glass-water and glass-salt solutions. The advantages and disadvantages of using sinusoidally varying quantities for electrokinetic measurements are discussed.
Variational Theory of the Radial Distribution Function
Authors: Richardson John M.
Published: April 2005

A variational approach to the calculation of the radial distribution function is presented. The approximations consist in the neglect of fourth-order correlation in the entropy and the use of a constant third-order correlation chosen to satisfy the third-order normalization condition. The average interaction energy, containing only pair terms, does not involve correlations higher than second order. Finally, one obtains approximate expression for the excess Helmholtz free energy as a function of the radial distribution function (r.d.f.) and macroscopic parameters. This free energy, when minimized with respect to the r.d.f. at constant temperature and density, yields an integral equation for the r.d.f. This theory has a simpler structure and yields thermodynamic functions in a more direct way than earlier theories. The theory has not yet been adequately tested; however, the author speculates that it will give good results for short-range forces but poor results for long-range forces.
Pyrolysis of Acetone and the Heat of Formation of Acetyl Radicals
Authors: Szwarc M. , Taylor J. Watson
Published: April 2005

Pyrolysis of acetone in the presence of an excess of toluene has been studied. The rate of the decomposition has been followed by the rate of formation of CO, the following sequence of reactions being assumed: CH3·CO·CH3→CH3+CO·CH3  slowCH3·CO→CH3+CO  fastThe reactions seem to be first order and unimolecular, the rate constant of the first step being determined as k=2.4·1014 exp (—72 000/RT) sec—1. It is assumed that the observed activation energy may be identified with CH3·CO–CH3 bond dissociation energy and on this basis the heat of formation of acetyl radical is calculated at — 10.8 kcal/mole.

The last result is compared with the findings resulting from investigation of the pyrolyses of diacetyl and of benzyl methyl ketone.

The validity of the toluene carrier technique is reviewed.
Evaluation of Force Constants from Raman Effect Data. Part 1. Molecules and Radicals of the Type XY4
Authors: Venkateswarlu K. , Sundaram S.
Published: April 2005

The force constants of 8 radicals and 6 molecules of the type XY4 belonging to the Td symmetry have been calculated using Raman effect data by the Wilson's F-G matrix method. Applying Badger's and Gordy's empirical rules, the X-Y internuclear distances have been calculated and compared with the available observed data.
Quantitative Comparison of the Approximate Dielectric Polarization Theories with an Exact One at Low Densities
Authors: Buckingham A. D.
Published: April 2005

The total dielectric polarization of a polar gas is expanded in inverse powers of the molar volume and the first term representing deviations from ideal gas behavior evaluated for an assembly of point polarizable dipoles, using the method developed by Buckingham and Pople. The approximate dielectric polarization equations of Debye, Onsager, Kirkwood, and Harris and Alder are expanded similarly and the corresponding coefficients of the term proportional to the first power of the density compared with the exact one. There is no term proportional to the density in the equations of Debye and of Onsager; also, to this order Kirkwood's and Harris' and Alder's theories are equivalent, both somewhat underestimating the total polarization. The use of Onsager's relationship for the dipole moment of a molecule is shown to be inappropriate for an imperfect gas.
On the Energy Dependence of Inelastic Molecular Collision Probabilities
Authors: Widom B.
Published: April 2005

It is pointed out that because of the uncertainty principle, cross sections for inelastic molecular collisions vanish at the threshold, in sharp distinction to their classical behavior. The dependence of the inelastic collision probability on the energy is deduced and found to be of the form k2l+1(a0+a2k2+a4k4+···),where k and l are the wave number and the total angular momentum quantum number, respectively, which describe the incident wave in case of de-excitation or the emergent wave in case of excitation. It is shown that because of this property of inelastic collisions, the pre-exponential factor in the collision theory of bimolecular kinetics contains only non-negative integral powers of the temperature.
Experiments on the Carnauba Wax Electret
Authors: Gerson Robert , Rohrbaugh J. H.
Published: April 2005

The strength of the applied electric field, the thickness of the slab being electrified, the time of electrification and the low temperature holding time before removing the field were varied for carnauba wax electrets. After approximately one hour the discharge current varied inversely as a power of the time since turning off the forming field, the power being close to one. The magnitude of this current depended on both the forming field strength and on the thickness of the electret. A very large discharge was obtained when the wax was electrified and discharged while not completely solid.

Dielectric constant measurements were made at temperatures between 27°C and 86°C, frequencies between 50 cps and 13 kc, and with superposed dc field strengths in the wax of zero, 3700 and 8100 volts per cm. The application of dc field was found to raise the dielectric constant at the higher temperatures.

The case for permanent dipole orientation and that for ionic space charges as the cause of the stored charge of the electret is examined, and it is shown that there are objections to each mechanism. An alternate explanation is suggested.
Line Broadening and Dielectric Relaxation in Compressed Gases
Authors: Phillips C. S. E.
Published: April 2005

An attempt is made to investigate the transition from resonance to relaxation spectrum by high-pressure research in the microwave region. Equipment has been developed for studying the dielectric constant and loss of gases and liquids in the K-band region up to 1000 atmospheres at temperatures up to 300°C. Measurements on a nearly spherical molecule of strong dipole moment (CHClF2), on a linear molecule of weak dipole moment (N2O), and on mixtures of CHClF2 with nitrogen are reported and a preliminary discussion of the results is given.
Oxidation of Methane with Nitrogen Dioxide
Authors: Bromberg Marvin L. , Taylor H. Austin
Published: April 2005

The reaction of methane with nitrogen dioxide has been studied in a flow system at temperatures from 600°—900°C with contact times of about 10—2 sec and in a static system from 350°—400°C and a total pressure of 250 mm. Initial rates have been related empirically and a discussion of the possible reactions occurring is presented.
Infrared Spectra of SiO2 from 400 to 600 cm-1
Authors: Reitzel J.
Published: April 2005

The frequencies of the infrared bands occurring between 400 and 600 cm-1 in α quartz, α cristobalite, and vitreous silica have been determined by a reflection method. The observed infrared spectra are compared with published Raman data.
Specific Heat of Lamellar Crystals
Authors: Newell Gordon F.
Published: April 2005

The theoretical basis for expecting the specific heat of lamellar crystals to be proportional to T2, at least over a sizeable range of temperatures, is re-examined and criticized in a qualitative way starting from the Born-von Kármán model of lattice vibrations. Arguments are presented to indicate that such a behavior implies special properties of the molecular forces other than those to be expected simply because of the lamellar structure. Numerous possible hypotheses are considered along with their consequences. From this, it seems doubtful that there is any simple semiphenomenological law that will fit specific heat data for all lamellar crystals in a manner comparable to the Debye law for nearly isotropic materials.