bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen Overvoltage and Atomic Hydrogen Electrodes
Authors: Van Rysselberghe Pierre
Published: January 2005

The fundamental thermodynamics and kinetics of hydrogen overvoltage are re-examined and improved. A precise definition of the transfer coefficient is given, the significance of the free energy of activation is discussed, and additional theoretical support is given for the interpretation of hydrogen overvoltage as being due to the establishment of reversible atomic hydrogen electrodes.
Theoretical Considerations Concerning Hammett's Equation. III. σ-Values for Pyridine and Other Aza-Substituted Hydrocarbons
Authors: Jaffé H. H.
Published: January 2005

Electron distributions in pyridine, pyrimidine, quinoline, isoquinoline, acridine, phenazine, and phenanthridine have been calculated by the LCAO MO method, and used to calculate Hammett's σ-values for the different positions in these compounds. The values are compared with the experimental values available for pyridine, quinoline, and isoquinoline, and satisfactory agreement is obtained. Formulas are given for the calculation of σ-values of similar compounds.
The Third Virial Coefficient in Polymer Solutions
Authors: Stockmayer Walter H. , Casassa Edward F.
Published: January 2005

With the aid of approximate models for the intermolecular potential energy, the third virial coefficient Γ3 in the virial expansion for the osmotic pressure of a dilute polymer solution has been determined as a function of the second coefficient and one additional parameter obtainable from intrinsic viscosity or light scattering measurements. The theory and experimental results agree in indicating that the ratio Γ3/Γ22 for most solutions is markedly less than the value of ⅝ given by the hard sphere molecular model proposed by others for the estimation of Γ3. The limitations are discussed under which light scattering may be used for evaluation of the virial coefficients.
Approximate Treatment of the Effect of Centrifugal Distortion on the Rotational Energy Levels of Asymmetric-Rotor Molecules
Authors: Kivelson Daniel , Wilson E. Bright
Published: January 2005

A first-order treatment yields the relation W=W0+A1W02+A2W0J(J+1)+A3J2(J+1)2+A4J(J+1)〈Pz2〉+A5〈Pz4〉+A6W0〈Pz2〉for the rotational energy W of a nonrigid asymmetric rotor. The A's are constants independent of the rotational quantum numbers (J, K−1, K+1) while W0 is the rigid-rotor energy. Pz is the operator for the component of angular momentum along the axis of quantization. Formulas are given for 〈Pz2〉 and 〈Pz4〉, based on continued fractions, as well as expansions useful for nearly symmetric cases. As a special case, the corrections are derived for transitions between the components of asymmetry doublets.
Calculation of Vibrational Relaxation Times in Gases
Authors: Schwartz R. N. , Slawsky Z. I. , Herzfeld K. F.
Published: January 2005

Vibrational relaxation times in gases are calculated with the method of Zener using an exponential repulsion in a one-dimensional model. The constants of the interaction potential are determined by fitting it to the data of Hirschfelder, et al. The great effect which some impurities have is accounted for either by their low mass and resultant high velocity or by ``near resonance'' transfers in which the vibrational quantum of the substratum is used partly to excite the vibration of the impurity, only the difference being transferred to translation. However, there are other impurities, the action of which cannot be explained in this manner. The theoretical values for the relaxation times are 10 to 30 times shorter than the experimental ones, which difference may be accounted for by the use of the one-dimensional model. Macroscopic equations governing the more complex relaxation processes in polyatomic gases and gas mixtures are developed.
The Compressibility of Krypton. I. An Equation of State for Krypton and the Weight of a Liter of Krypton
Authors: Beattie James A. , Brierley James S. , Barriault Roland J.
Published: January 2005

The compressibility of krypton containing 0.90 mole percent xenon has been measured from 0° to 300°C and over the density range 1 to 10 mole per liter. The constants of the Beattie-Bridgeman equation of state for the sample and for pure krypton were determined. The constants for pure krypton are R=0.08206, A0=2.4230, a=0.02865, B0=0.05261, b=0, c=14.89×104 in units of standard atmos, liter per mole, and °K(T°K=t°C+273.13). The equation for the sample studied reproduced the observed pressures with an average deviation of 0.16 percent. The weight of one liter of Kr at a pressure of one standard atmosphere is calculated from the molecular weight (83.7) and the above constants to be 3.745̄ g per liter at 0°C and 3.474 g per liter at 70°F.
The Compressibility of Gaseous Krypton. II. The Virial Coefficients and Potential Parameters of Krypton
Authors: Beattie James A. , Brierley James S. , Barriault Roland J.
Published: January 2005

The second and third virial coefficients of a sample of krypton containing 0.90 mole percent xenon have been determined from our compressibility measurements over the temperature range 0° to 300°C and to a density of 10 mole per liter. They are listed in Table II. The parameters of the Lennard-Jones (6, 12) potential for krypton are μ=2.044×10−58 erg-cm6, λ=0.438×10−102 erg-cm12, ε=238.4×10−16 erg, b0=58.40 cm3 per mole, θ=172.7°K, σ=3.591×10−8 cm, r0=4.030×10−8 cm. The representation of the second virial coefficient is quite satisfactory. The third virial coefficients diverge more than those of xenon from the theoretical values for a Lennard-Jones (6, 12) potential as tabulated by Bird, Spotz, and Hirschfelder. The observed second virial coefficients agree moderately well with the tabulated values of Buckingham and Corner for an inverse sixth and inverse eighth power attractive and an exponential repulsive potential when the tables are used in conjunction with the values of the arguments derived by Kane from data on the solid state of krypton and Born and Mayer's value of the exponent derived for neon.
Low Temperature Second Virial Coefficients for a Lennard-Jones Gas
Authors: Epstein Leo F.
Published: January 2005

For low temperatures, the second virial coefficient B(θ)=23πNr03G(θ)of a gas which follows a Lennard-Jones 6—s potential, Us(r)={ε/(s−6)}[6(r0/r)s−s(r0/r)6]where θ=ε/kT, can be represented by Gs(θ)∼−e+θ(3π/sθ)12 ∑ n=0βn(s)/θn.In two previous studies, formulas for βn(9) and βn(12) have been presented. In this paper, the relation for Gs(θ) is developed for the general case, using the method of steepest descents, and the first three coefficients β0(s), β1(s), and β2(s) are computed. The use of a Hooke's law potential and the quasi-ideal gas hypothesis yields the correct leading term in Gs(θ), but results in errors in β1(s) and β2(s).
The Dissociation of Ethyl Bromide and Iodide by Neutron Capture
Authors: Wexler Sol , Davies T. H.
Published: January 2005

A study has been made of recoil halogen species ejected from gaseous ethyl bromide and iodide after neutron capture. The results demonstrate that a fraction of the radio-halide fragments carry a positive charge. The fraction charged is 12 percent for the 4.4-hr Br80m, 25 percent for the 36-hr Br82, and 50 percent for the 25-min I128. The corresponding estimate for the 18-min Br80 is very approximately 18 percent. The positive charges are attributed to internal conversion processes in the stabilization of the compound nucleus formed by neutron capture. The fraction of positive recoil ions is interpreted as the minimum fraction of neutron capture processes which are followed by an internal conversion process. A comment is made upon the possible significance of the ions in the study of chemical reactions induced by radiative neutron capture.

A study of the 18-min Rb88 from β-decay of the 2.8-hr Kr88 was made using the procedures and equipment employed in the halogen experiments. The results show that all Rb88 atoms are positively charged as expected.
The Molecular Structure of Cyclobutane
Authors: Dunitz J. D. , Schomaker Verner
Published: January 2005

The cyclobutane molecule has been found by electron diffraction to have the following bond distances and bond angles: C–C, 1.568±0.02A; C–H, 1.098±0.04A; ∠HCH, 114±8°. On the average the ring is nonplanar, with dihedral angle 20° (+10°, −20°), but the equilibrium symmetry may be either D2d (puckered ring) or D4h (planar ring with low rigidity leading to large amplitude of out-of-plane bending). This point is discussed in connection with earlier spectroscopic work. The long bond distances found in four-membered rings are contrasted against the short distances in three-membered rings, and the strain energies, bond distances, and HCH angles of cycloalkanes are discussed in terms of modern valence concepts. It is suggested that the potential energy arising from a repulsion of the nonbonded carbon atoms may contribute significantly to the apparently anomalously high strain energy of cyclobutane. The repulsive force associated with such a potential is shown to account satisfactorily for the long C–C distances.
The Dissociation of Cyclopropane under Electron Impact
Authors: Field F. H.
Published: January 2005

The electron-impact-induced dissociations of cyclopropane are determined from the appearance of potentials of the several ions formed. In general, the dissociations involve a considerable amount of atomic rearrangement, and the evidence points to the opening of the carbon ring in the formation of the C3 ions. The energy required to convert cyclopropane to ethylene and methylene is found to 77 kcal/mole, from which it is estimated that the C–C bond dissociation energy in cyclopropane is at least 50 kcal/mole. The unexpectedly good agreement of the values of the heat of formation of an ion formed by electron impact from several different sources is noted, and a question is raised as to the role of activation energies in the electron-impact dissociations of polyatomic molecules.
A Note on the Vibrational Frequencies and the Entropy of Decaborane
Authors: Keller W. E. , Johnston H. L.
Published: January 2005

The infrared spectra of solid decaborane and of decaborane in a solution of carbon disulfide as well as the Raman spectrum of the solution have been recorded. A rough selection of fundamental frequencies is made; this, together with the molecular parameters from x-ray data, is used for calculating S298.160 of the gas, for which a value of 83.85 eu is obtained. This figure compares with that derived from thermodynamic measurements, namely, 87.36 eu.
The Franck-Condon Principle and Its Application to Crystals
Authors: Lax Melvin
Published: January 2005

The semiclassical Franck-Condon principle is shown to be related to the more rigorous (``exact'') quantum-mechanical perturbation formula in the following ways: (1) the Franck-Condon formula can be derived from the ``exact'' formula by using a mean value approximation or by neglecting certain commutators; (2) if the electric dipole moments are treated as approximately independent of position, the Franck-Condon and the ``exact'' absorption (or emission) spectrum have the same zeroth, first, and second moments, i.e., the same integrated spectrum, mean absorption frequency, and breadth; (3) the errors in higher moments than the second become relatively unimportant at high temperatures. If the electron-nuclear interaction is sufficiently strong the errors are unimportant even at absolute zero.

The use of a quasi-molecular description in a many particle problem is found to be possible only if the masses or stiffnesses are allowed to be temperature dependent.

A detailed analysis is made of the case in which the energy difference between the two electronic states is a linear function of the vibrational coordinates—and the latter are describable by normal modes. ``Exact'' formulas for the absorption and emission spectrum are obtained.
The Infrared and Raman Spectra of CF3OF
Authors: Lagemann R. T. , Jones E. A. , Woltz P. J. H.
Published: January 2005

The infrared spectrum has been obtained for gaseous CF3OF from 2 to 25μ. The Raman shifts have been measured for the liquid. Nine of the twelve fundamental vibration frequencies have been assigned and an interpretation made of the observed spectra on the basis that CF3OF belongs to point group Cs.
The Infrared Spectrum of SO2F2
Authors: Perkins W. D. , Wilson M. Kent
Published: January 2005

The infrared spectrum of sulfuryl fluoride has been investigated between 240 cm−1 and 4000 cm−1 with a prism spectrometer. Seven of the nine fundamentals have been observed and assigned to their appropriate symmetry species. Ten additional bands have been assigned as combinations or overtones. A partial force constant calculation has been made.
Physical Properties of Liquid Fluorine
Authors: Elverum Gerard W. , Doescher Russell N.
Published: January 2005

The viscosity, density, and surface tension of liquid fluorine and their dependence on temperature have been measured. The change in viscosity with temperature indicates that fluorine behaves as a normal liquid in the region studied. The results of the measurement of the density confirm a new much larger value for this property than previously accepted. Measurements of the surface tension given in this paper are in substantial agreement with values reported earlier in the literature if these early values are adjusted by means of the density determinations made by the authors.
The Influence of Temperature and State on Infrared Absorption Spectra: Methyl Iodide
Authors: Mador Irving L. , Quinn Ruth S.
Published: January 2005

The spectra of methyl iodide were determined in the range 2 to 15 microns for the vapor at 25°C, the liquid at 25° and −50°C, and the solid at −78°, −196°, and −269°C. Differences were observed in frequencies, intensities, and band shapes resulting from changes in state and temperature. There is band narrowing with reduction in temperature even in the solid. At the lowest temperatures, band splitting could be resolved in the degenerate bands as well as in the 1252 cm−1 nondegenerate fundamental. Several additional assignments are offered.
Ion Exchange Mechanism and Isotherms from Deep Bed Performance
Authors: Merriam C. Neale , Southworth Raymond W. , Thomas Henry C.
Published: January 2005

The rate laws for diffusion controlled chromatographic ion-exchange are discussed in connection with their application to deep beds of exchanger. Results of experiments with a carboxylic acid resin indicate that solid diffusion is the rate-determining step under the conditions of the experiments. An estimate is found for the value of the diffusion constant. The information is applied to the computation, from a chromatographic elution, of a cesium-sodium isotherm for the exchanger. This result is compared with a direct determination of the isotherm.
Raman and Infrared Spectral Data and Assignments for Dimethyldiacetylene
Authors: Ferigle Salvador M. , Cleveland Forrest F. , Meister Arnold G.
Published: January 2005

Raman displacements and quantitative depolarization factors, and wave numbers for the infrared bands in the KBr region have been obtained for dimethyldiacetylene in CCl4 and benzene solutions. Since the results of the present work are inconsistent with some of the previous assignments, these have been changed.

In particular, the line at 475 cm−1, which was previously considered an A1-type fundamental vibration, is now proved to be depolarized and is assigned as an Ē-type fundamental. Consistently with this change, the assignment of the 644 cm−1 line of diacetylene as a bending mode is considered. The previous assignments of both of these lines were the cause of the conflicting data existing in the literature between the bond length and the stretching potential constant of the central bond in the structure –C≡C–C≡C–.
The Thermodynamic Properties of Sodium Vapor
Authors: Benton A. , Inatomi T. H.
Published: January 2005

The free energy, enthalpy, entropy, and specific heat for both monatomic and diatomic sodium vapor have been calculated from spectroscopic data by the well-known methods of statistical mechanics. Also, the equilibrium constant Kp for the gaseous reaction Na+Na=Na2, as well as the entropies and enthalpies for the equilibrium mixture of these two species, were obtained. These calculations were made for the vapors as ideal gases at a pressure of 1 atmosphere, and for the temperature range 100°K to 2600°K. The results are presented in tables.
Substituted Methanes. IX. Raman and Infrared Spectra, Assignments, Potential Constants, and Calculated Thermodynamic Properties for CHClBr2 and CDClBr2
Authors: Pontarelli Donald A. , Meister Arnold G. , Cleveland Forrest F. , Voelz Fred L. , Bernstein Richard B. , Sherman Robert H.
Published: January 2005

Raman displacements, semiquantitative relative intensities, and quantitative depolarization factors for liquid chlorodibromomethane and deuterochlorodibromomethane, and infrared wave numbers and percent transmission curves for both the liquid and gaseous states in the region 400–4300 cm−1 were obtained and compared with previous data. A normal coordinate treatment (Wilson FG matrix method) was carried out, and a consistent set of potential constants for both molecules was determined, using a potential energy function containing all possible 2nd degree terms. Assignments were made for all observed bands. The heat content, free energy, entropy, and heat capacity at constant pressure were calculated for 12 temperatures from 100° to 1000°K.
The Measurement of Self-Diffusion in Solid Polymers
Authors: Bueche F. , Cashin W. M. , Debye P.
Published: January 2005

The self-diffusion constant of the macromolecules in plasticized polystyrene and pure poly-n-butyl acrylate has been measured over a wide variety of conditions by a radioactive tracer technique. Well-characterized polymer fractions were used throughout. Simultaneous measurements of the bulk viscosity were also made. From the data obtained one is able to show that within experimental error the product of the self-diffusion constant and the bulk viscosity is equal to a constant. This constant has been predicted by theory, and the agreement with the experimental value is good. Therefore, it appears possible to obtain diffusion constants directly from bulk viscosity data.
The Frictional Coefficient for Flexible Chain Molecules in Dilute Solution
Authors: Mandelkern Leo , Flory Paul J.
Published: January 2005

The frictional coefficient, f0, of a polymer molecule in dilute solution is assumed to vary directly as an average linear dimension of the chain. From this assumption equations are developed, as follows, which are analogous to those used successfully in the interpretation of intrinsic viscosity measurements; f0/η0 =KfM½α and Kf=P(〈r02〉/M)½ where α represents the factor by which the actual root-mean-square end-to-end distance exceeds the unperturbed distance (〈r02〉)½, M is the molecular weight, η0 the viscosity of the medium, and P should be a universal constant.

Data in the literature on the dependence on molecular weight of sedimentation constants and diffusion coefficients, extrapolated to infinite dilution confirm the conclusions drawn from these equations.
The Infrared Spectra of Naphthalene Crystals, Vapor, and Solutions
Authors: Pimentel George C. , McClellan A. L.
Published: January 2005

The infrared spectra of naphthalene in the gas phase, in solutions of carbon tetrachloride, carbon disulfide, and methyl cyclopentane, and as single crystals have been obtained in the region 3300–450 cm−1. The dichroism of three different single crystal planes, including the cleavage plane, has been studied using polarized infrared radiation. The frequencies were segregated into their respective symmetry classes on the basis of an assumed oriented gas model. Band contour data, together with a statistical comparison of the spectrum of the gas phase with the spectra of the condensed phases, establish the usefulness of this model.
The Velocity of Sound in Electrolytic Solutions
Authors: Barnartt Sidney
Published: January 2005

A relationship between the velocity of sound in electrolytes and concentration has been derived for extremely dilute solutions from the Debye-Hückel limiting law. The equation fits the observed data at higher concentrations when the theoretical coefficients are replaced by empirical constants.
The Prediction of Thermodynamic Properties of Nonideal Solutions from Turbidity Measurements
Authors: Babb A. L. , Drickamer H. G.
Published: January 2005

Turbidity measurements have been made on the systems CH3OH–i−C5H12CH3OH–n−C5H12CH3OH–n−C6H14near the critical solution temperature at seven atmospheres pressure and at a considerably higher pressure. The effect of pressure is to elevate the critical solution temperature and to decrease the minimum transmission. The wavelength dependence is consistent with the theory of Ornstein and Zernike. The change of fugacity with concentration is calculated as a function of temperature, pressure, and composition.
Effect of Various Gases on Potassium Ion Emission from Hot Platinum
Authors: Brady Edward L. , Zemany Paul D.
Published: January 2005

The effect of several gases on the emission of potassium ions from a hot platinum surface has been studied. It has been found that oxygen, carbon tetrachloride, bromine, and helium cause a marked decrease in the potassium emission; nitrogen has a smaller effect; and hydrogen causes an increase in the emission.
The Infrared Spectra of CF4 and GeF4
Authors: Woltz P. J. H. , Nielsen A. H.
Published: January 2005

The infrared spectrum of CF4 has been remeasured from 2–19μ and extended to about 33μ, and the infrared spectrum of GeF4 has been observed from 2–38μ.

Through the use of purer samples and more gas than in previous investigations, a large number of new overtones and combination bands were observed in CF4, and several bands were eliminated as impurities. Identifications of these bands are given. The infrared-inactive ν2 was observed, probably because of interaction with ν4, at 435 cm−1 in agreement with the Raman line at 437 cm−1.

In GeF4 the two active fundamentals ν3 and ν4 were observed at 800 cm−1 and 260 cm−1, respectively. Eight overtone and combination bands were discovered. From these the values of ν1 and ν2 were calculated to be 740 cm−1 and 200 cm−1, respectively. Compared with the fundamentals of GeCl4 and GeBr4, these frequencies seem reasonable. The most striking feature of the spectrum of GeF4 is the scarcity of bands as compared with both CF4 and SiF4.
The Potential Constants of Ethane
Authors: Hansen G. E. , Dennison D. M.
Published: January 2005

The infrared and Raman data of light and heavy ethane (C2H6 and C2D6) have been reexamined for the purpose of determining as accurately as possible the potential constants of the ethane molecule. In order to fill in some of the gaps in the spectroscopic data, additional high resolution measurements have been made on the infrared spectrum of heavy ethane which have given more precise values for the active fundamental frequencies and zeta-values. Resolution of the fine structure associated with the parallel band ν5* has given the value of the large moment of inertia of C2D6, thus completing the information required for the spectroscopic determination of the dimensions of ethane. The data yield, C–C distance=1.543A, C–H distance=1.102A, H–C–C angle=109°37′, and H–C–H angle=109°19′. The twenty-two distinct potential constants compatible with the D3d symmetry of ethane have been determined through their relationships to the normal frequencies and zeta-values of C2H6 and C2D6. The normal frequencies have been obtained by addition of anharmonic corrections to the spectroscopically observed fundamental frequencies. These corrections were estimated by means of the known anharmonic corrections for methane and the conditions imposed by the Teller product rule. The fundamental frequencies and zeta-values have been taken directly from the observed band centers and rotational spacings wherever possible. In the cases of resonance, the influence of the couplings were either calculated or estimated and the corresponding unperturbed values for the frequencies and zeta-values selected. The potential function is determined first in terms of a set of simple symmetry coordinates, and then reexpressed in terms of valence coordinates to permit comparison of the valence force constants of ethane and methane.
The Heat of Dissociation of Fluorine
Authors: Doescher Russell N.
Published: January 2005

Equilibrium pressure measurements of the dissociation of F2 have been completed with the use of (1) a nickel vessel coated stepwise by heating in contact with fluorine at temperatures up to 850°C and (2) a differentially applied manometer containing a fluorinated oil. This latter technique made it possible to carry out the measurements in the comparatively low temperature range 759° to 1115°K. The method consisted essentially in a direct comparison of the pressure variation with temperature of a quantity of fluorine with that of a quantity of nitrogen. Twenty-four determinations of the equilibrium constant were made, and in a plot of lnK as a function of 1/T, the points gave a straight line. The slope gave ΔH=37.7 kcal/mole as the mean heat of dissociation in the temperature range of the experiments for the reaction F2 (g)→2F (g). This ΔH value is in good agreement with values calculated from entropy quantities and values of lnK obtained from the line.
Lifetimes of Active Molecules. I
Authors: Marcus R. A.
Published: January 2005

The specific dissociation constants for various vibrationally excited molecules (methane, ethane, and propane) are inferred from an interpretation of experimental data on atomic cracking reactions and on the deuterization of free radicals. As was to be expected, these dissociation constants decrease with increasing number of degrees of freedom of the decomposing molecule.
Unimolecular Dissociations and Free Radical Recombination Reactions
Authors: Marcus R. A.
Published: January 2005

The steric and pressure effects associated with the recombination of free radicals both depend on the nature of the activated complex, and are therefore intimately related. From a consideration of the reverse process of unimolecular dissociation, some equations are derived for these properties using an extension of earlier transition state and quasi-unimolecular theories. The present formalism differs from previous formulations of the latter in a number of ways, particularly in the expression used for the density of quantum states of the high energy molecules. Subsequent applications of the theory tentatively suggest that essentially all vibrational degrees of freedom of these molecules can contribute their energy to the vibrationally excited molecules. Consequently, vibrational anharmonicity would appear to be an important factor in intramolecular energy transfer. The present paper is an extension of a previously developed theory for the recombination of methyl radicals and iodine atoms.
Proton Relaxation in Paramagnetic Solutions
Authors: Conger Robert L. , Selwood P. W.
Published: January 2005

Those paramagnetic ions, such as Fe+++, Mn++, and Gd+++, which are in S spectroscopic states; and those ions, such as Cr+++ and Cu++, which are effectively in S states through complete quenching of the orbital component, have been shown to produce reciprocal proton relaxation times proportional to the square of the magnetic moment. Those ions such as Co++, Nd+++, and Dy+++, with strong spin-orbital coupling, have been shown to be, in equivalent concentration, about ten times less effective.
Diffusion Coefficients of the Systems CO2–CO2 and CO2–N2O
Authors: Amdur I. , Irvine J. W. , Mason E. A. , Ross J.
Published: January 2005

The radioactive tracer, C14O2, has been used to measure diffusion coefficients for the systems CO2–CO2 and CO2–N2O in the temperature range −78° to 90°C. The apparatus, which is the Loschmidt type, uses saturation ionization currents as a measure of the extent of diffusion. The characteristics of this type of apparatus have been analyzed in detail to obtain working equations which permit use of experimental measurements at both small and large values of the time.

The present results, whose accuracy is estimated at 1.5 percent, agree with those obtained by other investigators using different experimental methods. Although the difference is small, 2.6±0.3 percent, the diffusion coefficient for the system CO2–N2O is consistently larger than that for CO2–CO2 over the entire temperature range.
The Reaction of Nitrous Acid with Hydroxylamine
Authors: Bothner-By A. , Friedman L.
Published: January 2005

Approximately equal quantities of N14N15O16 and N15N14O16 are produced by reaction of hydroxylamine hydrochloride and N15-enriched sodium nitrite in solution in O18-enriched water. The same reaction when carried out in a solution brought to a pH of 1 with gaseous HCl produces an excess of N14N15O16. In both experiments the concentration of N15N15O16 was accounted for on the basis of the reaction of nitrous acid with hydroxylamine to yield nitrous oxide molecules containing one nitrogen atom from each source. O18 exchange occurred to a greater extent in acid medium and the double tagged N2O so produced was mainly N14N15O18 rather than a mixture of the isomers N14N15O18+N15N14O18.

These observations lead to the following conclusions concerning the reaction mechanisms. In neutral solution most of the nitrous oxide produced is formed by dehydration of a symmetrical intermediate, probably hyponitrous acid. In acid medium a competitive dehydration of an unsymmetrical intermediate plays an important role. Mechanisms involving nitroxyl as an intermediate are untenable. Oxygen exchange is acid catalyzed and occurs exclusively with nitrous acid or with an unsymmetrical intermediate formed in the course of this reaction. Oxygen atoms from either nitrous acid or hydroxylamine appear in the product nitrous oxide.
Rotational Structure of the ν3 Raman Band of Methane
Authors: Stoicheff B. P. , Cumming C. , St. John G. E. , Welsh H. L.
Published: January 2005

A multiple reflection Raman tube and a high dispersion quartz spectrograph were used to investigate the fine structure of the ν3 band of gaseous methane. Sixty-eight maxima were measured, and evidence for all but one of the 15 theoretically predicted sub-branches was found. An evaluation of the rotational constants by combination relations for Raman and infrared frequencies gives three different B values for the upper vibrational state and surprisingly, three for the ground state. A more acceptable analysis, based on a single set of rotational constants for the ground state, B0=5.253 cm−1 and D0=1.9×10−4 cm−1, leads to B1 values for the various branches in the range 5.202 to 5.235 cm−1. The analysis gives ν0=3018.7 cm−1 and ζ1=0.056. The constants obtained for the ground state are also used in an analysis of the 2ν3 infrared band.
Emission and Absorption of Radiation by Spectral Lines with Doppler Contour
Authors: Penner S. S.
Published: January 2005

Equations are developed for observable intensities in emission and absorption for spectral lines with Doppler contour. It is shown that the theoretical relations which are usually employed in estimating effective temperatures of internal energy states (a) require slight modifications when proper allowance is made for the shape of spectral lines, and (b) are not valid unless the product of spectral absorption coefficient and optical density is sufficiently small. Illustrative calculations on several spectral lines belonging to the (0,0) band of the 2Σ→2Π band system of OH suggest that the conditions under which the basic relations hold are probably not satisfied for representative combustion flames.
A New Type of Disorder Affecting the Dielectric Properties of Long-Chain Esters
Authors: Crowe Robert W. , Hoffman John D. , Smyth Charles P.
Published: January 2005

The dielectric properties of a series of long-chain esters have been investigated in the solid state. Like other long-chain molecules containing 20 or more carbon atoms, most of the ester molecules showed evidence of hindered molecular rotation about their long axes in the crystal lattice. It was also found that higher dielectric constants resulted when the samples were rapidly frozen than when they were allowed to solidify gradually, the effect being more pronounced as the chain length was increased. In order to explain this behavior, it has been assumed that the esters may crystallize in an ordered lattice in which the dipoles are in a plane, or in a longitudinally disordered lattice in which some of the chains are reversed. In the latter case, the dipoles may or may not form two planes depending upon the position of the polar group in the chain. It has also been assumed that the degree of longitudinal disorder increases with increase in freezing rate. Once frozen in, however, it remains fixed until the sample is remelted.

The potential barrier hindering rotation has been assumed to be much higher in the ordered state than in the disordered state because separation of the dipoles should lower steric and dipole interaction in the latter. Since the rotational transition temperature is proportional to a potential energy difference V0 related to the barrier against rotation, the transition temperature should increase with increase in longitudinal order. In a completely ordered ester or a nearly symmetrical disordered ester, the barrier may be sufficiently high to raise the transition point to a temperature near or above that of fusion. The experiments agree with these assumptions.
Note on Configuration Probabilities
Authors: Siegert A. J. F.
Published: January 2005

The series obtained by Goldberger and Adams1 are derived by a simpler method and generalized to include systems of particles with Bose and Fermi statistics and spin, if spin dependent terms in the Hamiltonian are neglected.
The Infrared and Raman Spectra of F2CO, FClCO, and Cl2CO
Authors: Nielsen A. H. , Burke T. G. , Woltz P. J. H. , Jones E. A.
Published: January 2005

This paper combines earlier preliminary reports on F2CO, FClCO and Cl2CO into a complete report on the Raman and infrared spectra of these molecules. Details of measurement and handling of the samples are given. The fundamental frequencies observed in both Raman effect (liquid) and infrared (gas) and a large number of overtone and combination frequencies observed in the infrared have been identified and are collected in tables. The observed infrared band envelopes are described and compared with the band envelopes predicted on the basis of the molecular models. Resonance between ν2 and 2ν1 in F2CO and ν2 and ν1+ν4 in FClCO is discussed.
Spectroscopic Studies in the Near Ultraviolet of the Three Isomeric Dimethylbenzene Vapors. I. Absorption and Fluorescence Spectra of Para-Dimethylbenzene
Authors: Cooper C. D. , Sastri M. L. N.
Published: January 2005

The absorption spectrum of para-xylene between 2850 and 2350A was photographed using a 3-meter grating spectrograph, and the corresponding fluorescence spectrum between 3125 and 2720A was photographed with a Bausch and Lomb medium quartz spectrograph. The electronic transition involved is interpreted as 1A1g—1B3u with the 0, 0 band at 36733 cm−1. Progressions in the fluorescence spectrum involve the totally symmetric vibrations 829 and 1208 cm−1, while progressions of the corresponding frequencies 775 and 1185 cm−1 appear in the absorption spectrum. A weak portion of the spectrum is identified with a so-called forbidden transition involving the β1g-component of the 606εg+ benzene vibration. This β1g-vibration has a frequency of 648 cm−1 in the ground state and of 552 cm−1 in the upper state. The α1g-component of the εg+ benzene vibration in para-xylene has a lower state frequency of 458 cm−1 and the upper state value of 367 cm−1. The Tesla luminescence spectrum is interpreted in relation to the fluorescence and absorption spectra.
Visco-Elastic Effect in Solutions of Simple Particles
Authors: Fraenkel George K.
Published: January 2005

Calculations are performed on a simple model to show that dilute solutions of asymmetric particles possess a frequency dependent intrinsic viscosity and a rigidity. The model used is that of a solution containing elastic dumbbells, that is, particles consisting of two rigid bodies held together by elastic forces. Part of the rigidity would also arise from inelastic dumbbells and is caused by a force, usually neglected, as a result of Brownian motion. An additional rigidity is caused by the elastic nature of the dumbbells. At sufficiently low or high frequencies the results approximate a form similar to the ordinary dispersion formula for the dielectric constants of solutions and involve two relaxation times, one at low frequencies and one at high frequencies. The results for inelastic dumbbells are described by one relaxation time and follow the usual dispersion curve for all frequencies.
Determination of a Single Quadrupole for a Charge Distribution
Authors: Campbell Edwin S.
Published: January 2005

A method is given for the reduction to a single quadrupole of the second-order term in the Taylor series expansion of the potential defined by a charge distribution.
On the Lifetime of the Lower Triplet States of Benzene
Authors: Mizushima Masataka , Koide Shoichiro
Published: January 2005

Transition probabilities and selection rules are calculated for the lower triplet-singlet transitions of benzene. The relativistic spin-orbit coupling term combines the triplet state with an intermediate singlet state, and then dipole transition to the ground state occurs. The selection rules are deduced group-theoretically, and the transition probabilities are calculated using the LCAO one-electron approximation. The effect of vibration is discussed. The theoretical results obtained agree with Shull's and McClure's experimental results.
An Expansion Theorem of the Density Matrix
Authors: Kubo Ryogo
Published: January 2005

A general theorem is proved on the density matrix of quantum statistics. Let the density matrix be ρ{M}=exp[−β ∑ l=1MHl],where the operators Hl's are not always commutable. ρ{M} can be expanded in series of the form ρ{M}=(ΣM≧ ∑ i=1nmi, n≧0Σ{m1}M···{mn}M)ρ*{m1}···ρ*{mn}ρ̄{M−m1−···−mn},where {m1}M, ··· {mn}M are subsets of operators chosen from the set {M} and operators belonging to different subsets are commutable. The summation is over all the possible choices of the sets {m1}, ··· {mn}. ρ̄{k} is defined by ρ̄{k}=[Π{k}exp(−βHi)]s,where suffix s means the symmetrization by changing the order of the products. And ρ*{m} is defined by ρ*{m}=(Σ{k}m)(−)m−kρ{k}ρ̄{m−k},which is proved to be O(βm+1). Some possible applications are briefly discussed.
Orientation Effects in Solutions of Alcohols
Authors: Barker J.
Published: January 2005

An attempt is made to relate the free energy, heat, and entropy effects involved in the solution of alcohols in nonpolar solvents with the molecular interactions in the solutions. A simple model for the alcohol molecules is proposed, and the thermodynamic functions for a one-dimensional array, and in a simple case for a three-dimensional array, are determined by the methods of statistical mechanics. The results for the three-dimensional array are used to examine the assumption of ``repeatable step'' association with a definite equilibrium constant, and cast some doubt on the justification for this assumption. It is concluded that a more complete treatment of the three-dimensional array should provide a satisfactory basis for the complete description of the experimental facts.
Microwave Spectra of CHBr3 in the Region from 11 to 12.5 Centimeters
Authors: Kojima Shoji , Tsukada Kineo , Hagiwara Shigeo , Mizushima Masataka , Ito Takashi
Published: January 2005

The spectrum of rotational transition J=0→1 of bromoform has been estimated to lie in a 10-cm region. In this region, however, the spectroscopy has not yet been studied because of small absorption. Some of the present authors (S. K., K. T., and S. H.) had examined its detectability by the preliminary experiment with a cavity spectrometer. In the present paper more precise measurement using an absorption cell of 9 meters in length and its analysis by means of the theory proposed by some of the authors (M. M. and T. I.) are described. Thirty-two lines due to the hyperfine structure of the rotational transition were measured in the region from 2400 to 2660 mc/sec. The width of line was smaller than 2 mc/sec at 3 mmHg. The theory agreed well with the experiment. The value of the moment of inertia obtained here agrees with the result of electron diffraction, and this moment seems not to change appreciably by a low frequency deformation vibration. The quadrupole coupling constant of Br nucleus is nearly equal to that of CH3Br molecule.
Purification of Hydrocarbons for Use as Solvents in Far Ultraviolet Spectroscopy
Authors: Potts W. J.
Published: January 2005

The ultraviolet transmission of four hydrocarbons, n-heptane, isopentane, 3-methylpentane, and methylcyclohexane, are shown at various stages of purification. The particular advantages of each as a solvent in far ultraviolet spectroscopy is discussed with emphasis on the remarkable transmission of isopentane when purified.
Statistical Mechanics of Dilute Polymer Solutions. III. Ternary Mixtures of Two Polymers and a Solvent
Authors: Krigbaum W. R. , Flory P. J.
Published: January 2005

Expressions are derived for the osmotic pressure and turbidity of a dilute solution of two chemically dissimilar polymer species in a solvent. The relations obtained are contrasted with those derived through use of the free energy of mixing as given by the quasi-crystalline lattice model. Use of equations based on the lattice model to evaluate polymer-polymer interaction parameters from dilute solution data is shown to be valid only in special instances.
Gaseous Detonations. III. Dissociation Energies of Nitrogen and Carbon Monoxide
Authors: Kistiakowsky G. B. , Knight Herbert T. , Malin Murray E.
Published: January 2005

Detonation velocities have been measured in mixtures of cyanogen and oxygen at several pressures and in tubes of several diameters, with a reproducibility of the order of 0.1 percent. Thermodynamic calculations of detonation velocities were carried out for several assumed heats of dissociation of nitrogen and of carbon monoxide and for several experimental conditions. Methods are described for the extrapolation of experimental velocities to the limit of an infinite plane wave in ideal gases. The comparison of these extrapolations with thermodynamic calculations gives best agreement for DN2=9.76 ev and DCO=11.11 ev, the difference of experimental and calculated velocities averaging to 0.08 percent, with a standard deviation of 0.3 percent, which agrees with the predicted standard deviation. Several lower dissociation energies, which have been recommended on the basis of spectroscopic studies and of appearance potentials, give such poor agreement with these experimental data that they constitute very strong evidence in favor of the higher dissociation energies.
On the Reaction Field and Dielectric Constant of Polar Liquids
Authors: Frood D. G. , Dekker A. J.
Published: January 2005

It is shown that Onsager's formula for the dielectric constant of liquids, derived on the assumption of spherical molecules and a central mathematical dipole, still holds for extended dipoles of arbitrary position and direction as long as the molecules are spherical in shape.
The Chemical Effects of Ultrasonics
Authors: Griffing Virginia
Published: January 2005

A study of the effects of ultrasonics on the inversion of sucrose was made and negative results were obtained. In the light of these results one can make the following conclusions.

Chemical reactions attributed to ultrasonics can be classified according to three mechanisms. (1) Reactions due to cavitation never occur without the formation of bubbles. All of these reactions take place in the gas phase, are primarily thermal and are due to the heat developed during adiabatic compression. Thus, only reactants with an appreciable vapor pressure are affected. (2) Many reactions in the liquid phase are of secondary origin due to reactions with dissolved products of the primary reaction in the gas phase. Luminescense is also a secondary effect. (3) Some reactions are due to the uniform temperature elevation caused by absorption of acoustic energy of very high intensity in a short path length.
Specific Heat of Germanium between 20°K and 200°K
Authors: Estermann I. , Weertman J. R.
Published: January 2005

High precision measurements of the specific heat of germanium were carried out in the temperature region between 20°K and 200°K. Three samples of germanium were investigated: an extremely pure sample, one of intermediate purity (1018 impurity centers/cm3), and one with an addition of 0.006 atomic percent aluminum (2×1020 impurity centers/cm3). No anomaly such as reported by Cristescu and Simon was found in any of the samples. However, a small dependence of the specific heat on the concentration of impurity centers was observed.
Diffusion in the System C14O2–CO2 to 1000 Atmospheres Pressure
Authors: Timmerhaus K. D. , Drickamer H. G.
Published: January 2005

Diffusion coefficients are presented for the system C14O2–CO2 in the pressure range 100–1000 atmospheres, at temperatures 0°—25°—50°C. In the lower part of the range the results are consistent with those of Robb (see reference 2) and show little temperature coefficient for diffusion at constant density. At higher densities the temperature coefficient increases rapidly. The dense gas theory of Enskog is totally inapplicable, but the results are correlated in the form D=D0exp(−E/RT).The activation energy (E) at constant density and D0 are given as a function of density in a form useful for extrapolation.
The Growing of Single Crystals of Magnetite
Authors: Smiltens J.
Published: January 2005

Large, single crystals of magnetite, 1 cm in diameter and up to 4.3 cm long, of high purity and perfection have been grown from the melt. The density at 20° is 5.185, i.e., 99.58 percent of the x-ray density. The composition corresponds to stoichiometric Fe3O4 within analytical error. Phase diagram considerations, growing procedure, methods of chemical analysis, and composition data are discussed.
Infrared and Raman Spectra of Fluorinated Ethylenes. IV. 1,1-Difluoro-2-chloroethylene
Authors: Nielsen J. Rud , Liang C. Y. , Smith D. C.
Published: January 2005

The infrared absorption spectra of gaseous and liquid CF2:CHCl have been obtained in the regions 2–22μ and 2–38μ, respectively, with the aid of LiF, NaCl, KBr, and KRS-5 prisms. The Raman spectrum of the liquid phase has been photographed with a three-prism glass spectrograph of linear dispersion 15 A/mm at 4358A. Relative intensities and depolarization ratios have been measured for the stronger Raman bands. A complete assignment of fundamental vibration frequencies is given, the spectra are interpreted in detail, and thermodynamic functions are calculated for the temperature range 253–600°K.
Microwave Absorption and Molecular Structure in Liquids. IX. Measurement in Organic Halides at 10-Cm Wavelength
Authors: Branin F. H. , Smyth C. P.
Published: January 2005

The results of a systematic investigation of dielectric dispersion and absorption in the microwave region are discussed. Simple relations between the complex dielectric constant of an absorptive medium and the complex propagation constant of an electromagnetic wave within the medium are discussed in connection with a new interferometric method for measuring wavelength and absorption index directly within the medium. Results of measurements made at 10 cm wavelength by this method on twenty-five liquid organic halides are reported. The data of the present and previous measurements on these compounds are discussed in terms of distributions of relaxation times and, on the basis of absolute rate theory, the processes of dipole orientation and viscous flow in these liquids are compared.