bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of the Temperature and Pressure Coefficients of Conductivity and the Ultrasonic Effect in Dilute Electrolytes from Onsager's Theory
Authors: Barnartt Sidney
Published: January 2005

When ultrasonic waves are propagated through electrolytes, the periodic adiabatic compressions give rise to conductance changes which are a measure of the temperature and pressure coefficients of conductivity. It is shown that these coefficients can be calculated from Onsager's equation for symmetrical-valence electrolytes, if the coefficients at infinite dilution are known. Therefore, the magnitude of the ultrasonic effect can be computed. If the temperature coefficient at infinite dilution is known, then the pressure coefficient at infinite dilution may be obtained from a measurement of the ultrasonic effect at atmospheric pressure. The magnitude of the effect is derived for progressive and stationary plane waves in conductivity cells of uniform cross section. When the conductance of the electrolyte is determined with ac, the ultrasonic waves produce two side-band voltages of equal amplitude. For 10−4M KCl at 25°C in a favorable cell, the side-band voltages are computed to be approximately 53 microvolts per atmosphere acoustic pressure per volt applied.
On Polarization in Liquid Dielectrics
Authors: Jaffé George , LeMay Charlotte Z.
Published: January 2005

A theory of polarization originally developed for crystals is extended in such a way as to be applicable to dc measurements in liquid dielectrics. In Sec. II the general time dependent solution of the relevant differential equation is obtained by the method of eigenvalues. It leads to expressions for the ``charging current'' in Eq. (22) and the ``discharge current'' in Eq. (29), which are characteristic of liquids. In Sec. III the measurements and their results are described. They refer to solutions in hexane, and to pure hexane rendered conductive by radium radiation. Attempts to obtain photoconductivity were futile. In Sec. IV it is shown that the observations can be correlated by the theory of Sec. II provided the presence of two species of ions of different mobilities is assumed. A few cases of quantitative analysis are carried out. They lead to the determination of the mobility of the slower ions, and of the thickness of the polarization layers. In Sec. V some aspects of polarization in crystals are discussed in the light of the more recent development.
Note on the Nature of Conduction in Liquid Iron Oxide and Iron Silicates
Authors: Simnad M. T. , Derge G.
Published: January 2005

Current efficiency has been measured for the entire range of melts between iron oxide and the silica saturated slag. All compositions show some ionic conductivity, but the proportion of this type of conductance increases with the concentration of silica.
The Photochemical Decomposition of Benzene
Authors: Gibson G. E. , Blake Norman , Kalm Max
Published: January 2005

Under intense ultraviolet illumination with an A-H6 mercury arc, benzene solutions in rigid glass at liquid air temperatures are decomposed. If the solvent molecules contain hydrogen, hexatriene is formed (almost certainly identified by absorption spectrum and chemical behavior). In a solvent (perfluoro−2-methyl pentane) containing no hydrogen, the benzene decomposes to an entirely different product, not as yet certainly identified.
The Magnetic Susceptibility of Certain Organic Compounds. Part IV. The Constitution of Ortho, Meta, and Para Nitroanilines
Authors: Mikhail H.
Published: January 2005

Magnetic susceptibilities of o-, m-, and p-nitroanilines have been measured by the Gouy method. The experimental results showed that for a strong repelling group such as the amino group, the values for the op-derivatives are lower than the corresponding m-derivative. This was attributed to the fact that there is a tendency for the amino group to conjugate with the benzene nucleus in the case of o- and p-nitroanilines, accompanied by a lowering in their diamagnetic susceptibility values.
Equation of State Calculations by Fast Computing Machines
Authors: Metropolis Nicholas , Rosenbluth Arianna W. , Rosenbluth Marshall N. , Teller Augusta H. , Teller Edward
Published: January 2005

A general method, suitable for fast computing machines, for investigating such properties as equations of state for substances consisting of interacting individual molecules is described. The method consists of a modified Monte Carlo integration over configuration space. Results for the two-dimensional rigid-sphere system have been obtained on the Los Alamos MANIAC and are presented here. These results are compared to the free volume equation of state and to a four-term virial coefficient expansion.
Molecular Distribution Functions in a One-Dimensional Fluid
Authors: Salsburg Zevi W. , Zwanzig Robert W. , Kirkwood John G.
Published: January 2005

Exact expressions are derived for the molecular distribution functions in a one-dimensional fluid whose particles interact with a nearest neighbor pair potential. The pair distribution function for rigid spheres is found to be identical with Frenkel's result. The one-dimensional form of a new set of integral equations for the molecular distribution functions is examined. The superposition principle is found to be exact in a one-dimensional fluid with nearest neighbor interactions.
Thermodynamic Functions from Mayer's Theory of Ionic Solutions. I. Equations for Thermodynamic Functions
Authors: Poirier Jacques C.
Published: January 2005

For an ionic solute, Mayer has previously derived from statistical mechanics an analytical expression for a mean activity coefficient which, however, is not usually measured. From the partial molal free energy expression defining Mayer's activity coefficient, there are derived in this paper expressions for five usually measured thermodynamic functions. These are the change in partial molal volume with concentration; the change in apparent molal volume with concentration; the relative partial molal heat content; the relative apparent molal heat content; and the stoichiometric mean ionic molar activity coefficient. Formulas for these five functions involve the coefficients of thermal expansion and isothermal compressibility of the solution and solvent; the solvent dielectric constant and its pressure and temperature derivatives; and readily computable analytic expressions arising from the theory.
Electron Deficient Compounds. VII. The Structure of the Trimethylaluminum Dimer
Authors: Lewis Paul H. , Rundle R. E.
Published: January 2005

The trimethylaluminum dimer has a bridge structure with a skeletal symmetry of D2h within the accuracy of a structure determination by x-ray diffraction of single crystals. Bridge bonds, Al–C, equal 2.24A, vs Al–C bonds of 1.99A for the exterior, ``normal'' methyls. The bridge angle Al–C–Al=70°, the exterior angle C–Al–C=124°.

It is shown that a simple model provides the right order of magnitude for the heat of dimerization and indicates the relative importance of Al–C and Al–Al bonds. It is suggested that the sharp bridge angle required for good bridge bonding leads to metal-metal repulsions which should increase as the size of the metal increases. This probably plays a role in the instability and nature of polymers of the heavier trialkyl-metal compounds.
Space-Charge Layer and Distribution of Lattice Defects at the Surface of Ionic Crystals
Authors: Lehovec Kurt
Published: January 2005

It is shown that an electric potential exists between the surface and the bulk of ionic crystals. The potential is expressed in terms of the energies necessary for formation of lattice defects. The distribution of the potential and of lattice defects near the surface is calculated. The difference between the concentration of lattice defects near the surface and that in the bulk leads to a ``surface conduction.'' The magnitude of the potential, the thickness of the space-charge layer near the surface and the ``surface conduction'' are calculated for NaCl crystals using numerical values, calculated by Mott and Littleton [N. F. Mott and M. J. Littleton, Trans. Faraday Soc. 34, 485 (1938)] for the energies of formation of lattice defects. The effect of charged impurities in the crystals on the surface potential is discussed. The importance of the surface potential on diffusion, photoelectric effect, and photographic effect is mentioned.
On the Disorder in Crystalline 2,2-Dinitropropane at Room Temperature
Authors: Abrahams S. C.
Published: January 2005

2,2-dinitropropane forms face-centered, cubic crystals at room temperature, with a0=8.78±0.05A, and 4 molecules per unit cell. Molecular disorder is necessarily present in the cell, and several models are examined. Excellent agreement is obtained with a model in which the molecule possesses complete orientational disorder. Although the distinction between ``rotational'' disorder in time and in space is not possible, the following mechanism is suggested: while the disorder is complete at long range, there is a high degree of order at short range.
On Variational Principles for Irreversible Processes
Authors: Rosen Philip
Published: January 2005

A variational principle is formulated for diffusional processes such as heat and matter diffusion which is a modification of Onsager's principle of minimum dissipation. Also a variational principle is given for the flow of viscous incompressible fluids which has some analogy to Onsager's principle.
Theory of Centrifugal Distortion Constants of Polyatomic Rotor Molecules
Authors: Kivelson Daniel , Wilson E. Bright
Published: January 2005

The distortion constants ταβγδ are expressed in terms of inverse force constants and of the derivatives of the inertia tensor with respect to interatomic parameters. Harmonic potential functions are assumed. Relations that simplify the procedure for obtaining the required derivatives are obtained. Furthermore, rules are given that enable one to write down directly the derivatives with respect to certain common internal displacement coordinates. Group theoretical considerations are used to obtain some knowledge of the distortion constants.
On the Use of a Single Scale Factor in Atomic Wave Functions. I
Authors: Scherr Charles W.
Published: January 2005

Single scale factors are determined for converting 1s, 2s, and 2p self-consistent field orbitals of atoms in the first row of the periodic table into one another. Several simple relationships are found which allow predictions for fluorine and neon.
Resonance Energies of Benzene and Butadiene
Authors: Glockler George
Published: January 2005

The resonance energy of benzene based on an ethane-ethylene-like Kekulé structure is 74.86 kcal. The similar quantity for butadiene is 17.28 kcal. These quantities are independent of the value of the heat of sublimation of carbon. They are obtained from the heats of atomization of the appropriate molecules or from the heats of hydrogenation of the pertinent related compounds. Both methods yield the same results if properly applied.
Scattering Factors for Certain Polydisperse Systems
Authors: Goldstein Martin
Published: January 2005

Scattering functions for systems of polydisperse rods are calculated. The reciprocal scattering functions are found to have a greater downward curvature the greater the polydispersity. It is shown that this increased curvature is a property of polydisperse systems under very broad conditions.
Radial Distribution Functions and the Equation of State of Monatomic Fluids
Authors: Zwanzig Robert W. , Kirkwood John G. , Stripp Kenneth F. , Oppenheim Irwin
Published: January 2005

An approximation is obtained for the radial distribution function in a fluid whose molecules interact with the Lennard-Jones potential. Calculations of the equation of state, the internal energy, and the compressibility are presented and compared with experiment. At temperatures and volumes higher than the critical, agreement with experiment is satisfactory. A systematic method is developed of modifying the theoretical radial distribution function so that calculated thermodynamic quantities agree with their experimental values. In the liquid phase, slight modifications are needed to obtain agreement with experiment.
The Use of Free Electron Model Wave Functions in the Derivation and Representation of LCAO MO Wave Functions of Conjugated Molecules
Authors: Jaffé H. H.
Published: January 2005

A simple relation between free electron model and LCAO molecular orbital wave functions is derived for linear and cyclic conjugated molecules involving no branching of the π-electron system. On the basis of this relation LCAO MO wave functions and their energies can be calculated without solution of secular equations or extensive numerical computations, and simple analytic expressions for the wave functions and energies can be derived. The method assumes equal resonance and Coulomb integrals in the conjugated system but does not require neglect of overlap integrals. The types of molecules for which the method is most appropriate are discussed. For other molecules the LCAO MO WF's derived from FEM WF's may be improved by perturbation calculations. The relations are also shown to hold for molecules containing heteroatoms and branched π-electron systems if the FEM WF's are replaced by the FEM-like WF's derived. Finally, a simple method of graphic representation of LCAO WF's is proposed and illustrated.
Dielectric Constant Theory for Polar Liquids
Authors: Brown William Fuller
Published: January 2005

In Debye's theory of polar fluids, the electrostatic interaction of the molecules was taken into account by introducing the Lorentz local field formula. This formula is inaccurate, especially for liquids. More recent treatments are of two types. One, developed by Onsager, treats one molecule explicitly and replaces the others with a continuum. The other, developed by Kirkwood, uses the statistical mechanical theory of strongly interacting molecules. The second method is rigorous and can be used to derive the approximate results of the first; nevertheless, the first has remained popular because of its simplicity. The treatment presented here attempts to combine the rigor of Kirkwood's method with the simplicity of Onsager's. This is done by use of several useful theorems of classical electrostatics, which are overlooked when dielectrics are treated in the traditional textbook manner. The result is shown to be equivalent to Kirkwood's; but it is in a more flexible form, and it can, therefore, be used to derive approximations of a more general class.
The Effect of Pressure on Diffusion in Liquid Sulfur
Authors: Cova D. R. , Drickamer H. G.
Published: January 2005

Diffusion coefficients have been measured in liquid sulfur to 2500 atmospheres pressure for isotherms at 140°C, 150°C, 175°C, and 210°C. One isotherm was also obtained at 195°C for sulfur containing 0.75 percent iodine. The motion in the viscous region is characterized by very small activation volumes which indicates that the moving segment is very small. This shows why the drop in diffusion rate in the transition region is small compared with the increase in viscosity. The iodine reduces the ``effective temperature'' 10–15°C. Above 1200–1500 atmospheres only one form of liquid sulfur seems to exist.
The Detection of Atoms and Free Radicals in Flames by Mass Spectrometric Techniques
Authors: Foner S. N. , Hudson R. L.
Published: January 2005

A mass spectrometric method employing a molecular beam gas sampling system has been developed for the detection of atoms and radicals in chemical reactions. Background signals have been virtually eliminated by mechanically modulating the molecular beam and applying phase detection to the ion signal. The application of the method is illustrated by examples of low-pressure flames. In the hydrogen-oxygen flame H, O, and OH have been positively identified. The mass spectrum of a simple hydrocarbon flame, such as the methane-oxygen flame, is complicated by the presence of a large number of stable components generated in the flame. In the methane-oxygen flame the stable intermediates include C2H2, CO, CH2O or C2H6, CH4O, and C4H2. The methyl radical has been clearly identified in the methane-oxygen flame. A search for the HO2 radical in the hydrogen-oxygen flame was made without obtaining positive results. The HO2 detection problem is discussed in detail.
Thermal Expansion of Zirconium between 298°K and 1600°K
Authors: Skinner Gordon B. , Johnston Herrick L.
Published: January 2005

The average coefficients of thermal expansion of hexagonal zirconium between 298°K and 1143°K are 5.5×10−6 deg−1 along the a axis, 10.8×10−6 deg−1 along the c axis, and 7.2×10−6 deg−1 for a randomly oriented polycrystalline sample. The average value of the linear coefficient of expansion of cubic zirconium between 1143°K and 1600°K is 9.7×10−6 deg−1. At the transition there is a decrease in volume of 0.66 percent.
Adsorption on Proteins and Interactions between Protein Molecules in Solution
Authors: Hill Terrell L.
Published: January 2005

A theoretical approach to the problem of the interconnection between adsorption on proteins and interactions between protein molecules in solution is outlined. As an illustration, the second virial coefficient and related quantities are discussed. A more detailed account of this work will be published in the Annals of the New York Academy of Sciences.
On the Presence of Free Chlorine in Sodium Chloride Crystals Containing Color Centers and Color Center Precursors
Authors: Hacskaylo Michael , Otterson Dumas , Schwed Philip
Published: January 2005

Measurements have been carried out of the free chlorine content of NaCl crystals subjected to electrolysis before and after exposure to x-rays, as well as the free chlorine content of normal NaCl crystals after irradiation. It has been found that crystals which have not been irradiated contain no free chlorine, whereas those exposed to x-rays contain between 0.1 and 0.6 free chlorine atom per vacancy pair.
Empirical Considerations of Entropy. I. The Entropies of the Oxy-Anions and Related Species
Authors: Cobble James W.
Published: January 2005

The partial molal entropies for oxy-anions and related species have been correlated as a function of the charge, interatomic distance, and certain structural factors. An equation is given by which the entropy for unknown species can now be estimated fairly accurately. In the few cases where the method does not give good agreement, the data are open to suspicion as indicated by other independent observations. Some applications and extensions of the method are indicated for future study.
Empirical Considerations of Entropy. II. The Entropies of Inorganic Complex Ions
Authors: Cobble James W.
Published: January 2005

A method is proposed by which the partial molal entropies of aqueous complex ions can be correlated in a simple manner as a function of the ratio of their charge to interatomic distance. The agreement obtained between the observed values and those calculated by this method has been shown to be within the accuracy of the experimental data. It is also demonstrated that when the complexing agent is water alone (i.e., no complexing) the proposed equation reduces to an expression similar to that previously obtained by Powell and Latimer for simple monatomic ions.
Vibrational Spectra of Fluorinated Aromatics. IV. 1,2,4,5-Tetrafluorobenzene
Authors: Ferguson E. E. , Hudson R. L. , Nielsen J. Rud , Smith D. C.
Published: January 2005

The infrared absorption spectra of gaseous and liquid 1,2,4,5-tetrafluorobenzene have been obtained in the region 2–22μ with the aid of LiF, NaCl, and KBr 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 made and the spectra are interpreted in detail. The values of the nonplanar fundamental frequencies are checked by normal coordinate analysis.
Interactions of Randomly Disordered Molecules
Authors: Atoji Masao , Lipscomb William N.
Published: January 2005

Some generalizations of previous theoretical expressions for the mean potential energy of interaction between two randomly disordered molecules have been derived and have been generalized to interactions in a molecular lattice. Values of the heats of vaporization of some tetrahedral molecules and halogens have been calculated, with results in reasonable agreement with experimental values. Application of the theory to the heat of sublimation of a disordered solid, hexachloroethane, is also discussed.
Influence of Irradiation on Discharge Current in an Ozonizer
Authors: Deb S. , Saha A. K. , Ghosh M.
Published: January 2005

The paper outlines the principal characteristics of the effects of irradiation on the discharge current in an ozonizer. The ``electronic surface charge theory'' of the effect developed by Deb and Ghosh, on a suggestion of Mitra, is explained and is further extended by taking into account the role played by the negative ions formed in the discharge space. It is assumed that the effect of irradiation is to decrease the charges deposited on the surface and to increase those in the volume. The former reduces the discharge current due to the neutralization of the surface charges and the latter increases the main discharge current due to the applied voltage. The net effect is generally a decrease if conditions are favorable for the capture of the electrons in the volume by neutral gas molecules, leading to the formation of negative ions. In all other conditions the effect is generally an increase. It is shown that the theory, in its extended form, is able to account for the origin and the characteristics of both the positive and the negative effects. Numerical calculations of the various rate processes involved in the proposed mechanism are also made. It is shown that the relative magnitudes of these processes are such as to support strongly the ``electronic surface charge theory'' of the effect.
Hot Atom Recoils from C12(γ,n)C11
Authors: Rowland Frank S. , Libby W. F.
Published: January 2005

Simple carbon systems have been irradiated with the University of Chicago betatron, producing C11 atoms by the reaction C12(γ,n)C11. The distribution of the radioactive atoms between CO and CO2 for samples irradiated in the liquid phase was found to be 95–100 percent CO, and for samples irradiated in the solid phase about 50 percent of each oxide. A mechanism for these results is proposed.
The Existence of Multiply Charged Molecular Ions of HBr, HCl, and DCl
Authors: Johnston W. H. , Arnold J. R.
Published: January 2005

Experimental evidence is presented for the DCl+1, HCl+1, DCl+2, and HBr+2 molecular ions, using a modified Consolidated-Nier mass spectrometer. Although Cl+3, Br+3, and A+3 were observed, no evidence was obtained for H1,2Cl+Z, or HBr+Z above Z=2. This result contradicts the recent calculations of Magee and Gurnee2 that HBr+3 and HBr+4 would be stable toward dissociation. Finally a crude calculation is done assuming hydrogen 1s atomic orbitals which agrees amusingly with the experiments.
Rotational Line-Width Measurements on NO, HCl, and HBr
Authors: Weber D. , Penner S. S.
Published: January 2005

Quantitative measurements of apparent rotational line half-widths are described for NO, HCl, and HBr. Theoretical relations, which apply to vibration-rotation bands with spectral lines of uniform half-width and Lorentz contour, have been used to obtain apparent rotational half-widths from experimental data for CO and for NO.
Electron Impact Studies of the Vinyl Ion and Radical
Authors: Field F. H.
Published: January 2005

The appearance potentials of the vinyl ion as produced by electron impact from eight different compounds have been measured. The corresponding values of the heat of formation of the vinyl ion vary from 274 to 292 kcal/mole, with an average value of 281.5 kcal/mole. It is pointed out that no definitive explanation for the variation can be given.

The heat of formation of the vinyl radical is found to be 82.3 kcal/mole, which leads to a value of 122 kcal/mole for the first C–H bond dissociation energy in ethylene. The ionization potential of the vinyl radical is 200.5 kcal/mole=8.69 ev.
Heat Capacity and Thermal Diffusivity of Silver Bromide
Authors: Pochapsky T. E.
Published: January 2005

Rapid heat capacity measurements are reported for silver bromide at temperatures in the range from room temperature to 411°C. Thermal diffusivities and conductivities are derived for the same temperature range from an analysis of the cooling of a platinum wire embedded in the bromide. The results show that vacancy equilibrium is established in less than about 10−4 second above 350°C.
A Note on Work Functions and Chemical Potentials
Authors: Van Rysselberghe Pierre
Published: January 2005

It is shown that the work of extraction (equal to the product of work function by molar charge) cannot be considered as equal to the chemical potential. In particular the electron work function of a metal does not correspond to the chemical potential of the electron in the metal and cannot be used in attempts at obtaining absolute metal-solution potential differences. The exact relationships involving these quantities are derived and linked with Galvani and Volta potential differences.
The Vibrational Spectra and Structure of Nitrogen Tetrasulfide
Authors: Lippincott Ellis R. , Tobin Marvin C.
Published: January 2005

The infrared and Raman spectra of nitrogen tetrasulfide (N4S4) are presented along with the infrared spectrum of nitrogen hydrogen sulfide (N4S4H4). These data have been considered in terms of the several proposed structures for nitrogen tetrasulfide and have been found to be consistent with a cage structure of D2d symmetry. With the aid of a normal coordinate analysis of the nondegenerate symmetry species, a complete assignment of frequencies to their normal modes of vibration has been made for nitrogen tetrasulphide. A tentative assignment of frequencies is also given for nitrogen hydrogen sulfide.
Free-Electron Network Model for Conjugated Systems. I. Theory
Authors: Ruedenberg Klaus , Scherr Charles W.
Published: January 2005

The free-electron model for conjugated systems is consistently developed as the limiting case of a three-dimensional quantum-mechanical treatment of the π electrons in such systems. Joint conditions (for branching points) and boundary conditions (for free end points) are derived and the hermiticity of the Hamiltonian is shown. A matrix formulation of the theory is established which makes the application to large systems feasible, and at the same time leads to a close analogy with the LCAO model (LCAO MO treatment considering only nearest neighbor interactions). Quantities analogous to the quantities q (the charge in an atomic orbital) and p (the bond order) are defined, and special attention is given to alternant conjugated systems for which a population theorem, analogous to the one in LCAO theory, is valid.
Virial Expansion for Mixtures of Rigid Spheres
Authors: McLellan A. G. , Alder B. J.
Published: January 2005

The equation of state for a binary mixture of rigid spheres of arbitrary size ratio is developed up to the fourth virial coefficient. The superposition approximation is employed and thus the fourth virial coefficient is inexact; however, the second and third are evaluated precisely. The important thermodynamic functions are tabulated as well as the changes in these functions upon mixing at constant free volume. The fourth virial coefficient is evaluated exactly for the case where one of the components is a point sphere and the result is compared with the approximate one.
Photochemical Evidence Relative to the Excited States of Oxygen
Authors: Volman David H.
Published: January 2005

Recent results on the formation of ozone from oxygen photosensitized by mercury vapor at 2537 A show that the effects of foreign gases on deactivating the excited state of oxygen formed by energy transfer are He, A, N2, and CO2 in order of increasing efficiency. However the efficiencies of A and N2 are about the same. Consideration of the process of deactivation by collision indicate that the 3Σu+ state of O2 is not the excited state involved, and that the excited state is vibrationally excited O2 in the ground state, 3Σg−. Analogous arguments applied to the unsensitized reactions at 1849 A, where the effects of the added gases are in opposite order, show that after the absorption of light predissociation occurs from the 3Σu− state of O2.
Structure of Ozone from the Microwave Spectrum between 9000 and 45 000 Mc
Authors: Hughes Richard H.
Published: January 2005

Although there have been numerous investigations of the structure of ozone during the last thirty years, no studies yielded universally accepted structures until the recent infrared and microwave work. The microwave spectrum gives structural information which can be interpreted unambiguously and which is more accurate than that obtained by other methods. In this study the rotational spectra have been obtained for six isotopic ozone molecules between 9000 and 45 000 Mc. The spectra of four of them have been identified to the extent necessary to determine the spectral constants, from which moments of inertia have been calculated. By taking the moments of inertia for a molecule two at a time, structural parameters of the molecules have been calculated. Because of the inertia defect, the three different sets of parameters for each molecule have small discrepancies. There is remarkable consistency between the parameters for the different molecules. Although the resultant bond length of 1.278±0.002 A is consistent with the electron diffraction value of 1.26±0.02 A, the apex angle value of 116° 45′±30′ is inconsistent with the diffraction value of 127°±3°. The dipole moment of ozone has been determined to be 0.58±0.05 Debye unit from the Stark effects of two low J-transitions.
Vibrational Spectra of Organosilicon Compounds. I. Vinyltrichlorosilane
Authors: Shull E. R. , Thursack R. A. , Birdsall C. M.
Published: January 2005

The Raman spectrum, including qualitative depolarizations of liquid vinyltrichlorosilane, and the infrared spectra of liquid and gaseous vinyltrichlorosilane have been obtained. The spectroscopic data indicate that the vinyltrichlorosilane molecule has Cs symmetry. An assignment of the observed frequencies has been made on the basis of this symmetry.
Nuclear Magnetic Relaxation of Nonuniform Systems
Authors: Broersma S.
Published: January 2005

The relationship between the relaxation time measured for a heterogeneous system and the relaxation times and concentrations of the components is discussed. In general, the value of the ``average'' relaxation time observed is dependent upon the method of measurement. When the relaxation effects are completely averaged out within the time of measurement, the system behaves as a single phase while the relaxation time is determined by the time average (or mass average) of 1/T. If no averaging takes place at all the signal strength is determined by the sum of the magnetizations of the components, each with its own relaxation time.

In the transition case one should use the concept ``amount of relaxation during time t'', ∫0t dt′/T. Two examples of this transition have been examined experimentally. They are determined by the phenomena of diffusion and adsorption, both of which are able to delay the completion of the ``relaxation life cycle.'' The protons in hydrocarbons mixed with paramagnetic salt crystals, exhibit the properties of a two phase system; also dilute solutions of paramagnetic ions in water. In principle it is possible to obtain information about self-diffusion in liquids, hydration of ions, dispersivity of solid paramagnetic material.

Instrumental techniques used in the detection of the signal are described.
Raman Spectra of Hydrogen Peroxide in Condensed Phases. I. The Spectra of the Pure Liquid and Its Aqueous Solutions
Authors: Taylor Robert C. , Cross Paul C.
Published: January 2005

The Raman spectrum of liquid 99.5% H2O2 has been obtained at 30° and −40°C and compared with the spectrum of 90% D2O2 at −40°C. Three bands not previously reported were observed and their assignment, together with that of the remaining bands, is discussed.

Raman spectra were also obtained for aqueous solutions at 30° and −40°C over the complete concentration range. The interpretation is qualitatively in agreement with the results of other work which indicate that the addition of hydrogen peroxide to water results in more extensive hydrogen bonding and an increased degree of order in the solutions.
On the Coupling Between Electronic and Nuclear Motions in Molecules
Authors: Wu Ta-You , Bhatia A. B.
Published: January 2005

The energy due to the coupling between the electronic and the nuclear motion in a molecular system has been calculated for the normal state of the hydrogen molecular ion H2+ and the lowest 1Σ and 3Σ state of the hydrogen molecule H2. It is found that this coupling is represented by a repulsive potential which is of the same order of magnitude as the van der Waals interactions at distances where the latter is important. Thus in any theoretical calculation of the interaction between light neutral atoms, it is necessary to include this coupling between the electronic and the nuclear motions.
Free Radicals by Mass Spectrometry. VIII. The Ionization Potentials of Para-, Ortho-, and Meta-Xylyl Radicals
Authors: Farmer J. B. , Lossing F. P. , Marsden D. G. H. , McDowell C. A.
Published: January 2005

The vertical ionization potentials of the para-, ortho- and meta-xylyl radicals as measured by electron impact are found to be 7.46±0.03, 7.61±0.05, and 7.65±0.03 v, respectively. The thermal dissociation of the para- and ortho-xylyl radicals to form the quinodimethanes has been observed. The meta-xylyl radical was found to have a considerably greater thermal stability.
Velocity-Diameter and Wave Shape Measurements and the Determination of Reaction Rates in TNT
Authors: Cook Melvin A. , Horsley G. Smoot , Partridge W. S. , Ursenbach W. O.
Published: January 2005

Velocity (D) vs diameter (d) curves for low density TNT of various grain sizes were obtained over a range of diameters from the minimum propagation or critical diameter dc to above the smallest diameter dm* required for detonation at the theoretical maximum velocity D*. Also measurements of the shapes of the wave fronts were made at different diameters and particle sizes. The results were interpreted by means of the theories extant of the influence of reaction rates in detonation. The velocity-diameter curves were shown to have the shapes required by the ``nozzle theory'' but not those predicted by the ``curved front'' theory. The results were in accord with the Eyring surface burning theory in which the flame front is postulated to penetrate the individual grains at a radially constant velocity. Critical diameters were found to occur at the diameters at which D/D* was about 0.75. The steady state wave fronts were found to be essentially spherical with a radius of curvature Rm varying from 0.7 d near the critical diameter to about 1.9 d at d=20 cm for the coarsest product studied. Also Rm/d was found to increase with decreasing particle size at a given diameter in the D/D*<1.0 region and at a lower rate at and above dm*.
Studies of the Interaction between Atoms and Stable Molecules. VI. The Interaction of a Be Atom with an H2 Molecule
Authors: Griffing Virginia , Hoare J. P. , Vanderslice Joseph T.
Published: January 2005

A molecular orbital approach has been made to the reaction between a Be atom and an H2 molecule. Two reactions have been considered: (1) Be+H2→BeH2; (2) Be+½H2→BeH. Correlation diagrams have been constructed following the general rules developed in the previous papers of this series. LCAO-SCF calculations have confirmed the conclusions drawn from the correlation diagram of reaction (1). Theory and experiment have been found to be in qualitative agreement.
Long Wave Ultraviolet Spectrum of Formaldehyde
Authors: Cohen A. D. , Reid C.
Published: January 2005

The long wavelength spectrum of formaldehyde has been investigated in absorption and in emission, both in the gas phase and in the condensed phase. Difficulties in the assignment of certain lines in the spectrum have been satisfactorily resolved. The temperature coefficient of the α band shows that it is a hot band arising from a lower state involving the 1280 cm−1 asymmetric vibration.
Aspects of the Statistical Thermodynamics of Real Fluids
Authors: Reiss Howard , Frisch H. L. , Helfand E. , Lebowitz J. L.
Published: January 2005

By extending the ideas previously applied to the statistical mechanical theory of hard sphere fluids of Reiss, Frisch, and Lebowitz, an approximate expression has been determined for the work of creating a spherical cavity in a real fluid. In turn the knowledge of this entity permits an evaluation of properties such as the surface tension and the normal heats of vaporization of fluids and the Henry's law constants of fluid mixtures. The agreement between the calculated and experimental properties is satisfactory.
Ionization of Strong Electrolytes. VIII. Temperature Coefficient of Dissociation of Strong Acids by Proton Magnetic Resonance
Authors: Hood G. C. , Reilly C. A.
Published: January 2005

The proton magnetic resonance of nitric and perchloric acid solutions over the entire concentration range has been used for determining the dissociation constants at 0, 25, and 70°C. Excellent agreement with earlier data for nitric acid derived from Raman spectra was obtained.
Dimensions of Long-Chain Molecules with Restricted Internal Rotation and Variable Bond Length and Angle
Authors: Taylor William J.
Published: January 2005

Exact formulas are obtained for the mean square length and radius of an unbranched chain molecule of n equivalent bonds, with restricted internal rotation about each bond and variable bond length and angle. It is assumed only that each of the internal coordinates is distributed independently of the others. This model is not entirely realistic, but is justified for the bond stretching and bending motions because of the small effect they have on the chain dimensions, shown to be of the order of a few tenths of one percent at normal temperatures.
Potential Energy Constants, Rotational Distortion Constants, and Thermodynamic Properties of B11H3CO, B11D3CO, B10H3CO, and B10D3CO
Authors: Sundaram S. , Cleveland Forrest F.
Published: January 2005

Potential energy constants have been obtained for the BH3CO molecule by use of the Wilson FG matrix method. The derivatives of the moments of inertia tensor components, with respect to the symmetry coordinates, of an axially symmetric ZX3YW molecule of C3v symmetry have been evaluated. With these derivatives and the elements of the potential energy matrices, the rotational distortion constants for B11H3CO, B11D3CO, B10H3CO, and B10D3CO have been calculated. The calculated values are in good agreement with the values obtained in the microwave experiments by Gordy et al. The heat content, free energy, entropy, and heat capacity have been calculated for the four molecules for the ideal gaseous state at 1 atmos pressure, with a rigid-rotor harmonic-oscillator approximation.
Kinetics of the Hydrolysis of Acetyl Chloride
Authors: Cairns E. J. , Prausnitz J. M.
Published: January 2005

The hydrolysis of acetyl chloride in mixed solvent of acetone-water was investigated by means of an electrical conductance method. The temperature was varied over the range of −35°C to +10°C, and the solvent composition was varied over the range of 10 to 25% of water by volume. The reaction was found to be first order with respect to water and first order with respect to acetyl chloride over the range investigated. A strong dielectric constant influence was found, manifesting itself in an influence on the isodielectric entropy of activation. This effect was consistent with electrostatic theory and followed the dipole-dipole type of dielectric constant dependence. The dipole moment of the activated complex was estimated to be 16 debyes.
Spin Densities in Odd Alternant Hydrocarbon Radicals
Authors: Lefebvre Roland , Dearman Henry H. , McConnell Harden M.
Published: January 2005

The spin densities at the starred and unstarred carbon atoms of odd alternant hydrocarbon radicals have been calculated using the method of alternant molecular orbitals introduced by Löwdin. The spin densities at unstarred positions are shown to be negative in sign and to depend upon the electron correlation parameter θ. Observed spin densities on one carbon atom can be used to estimate θ and to calculate spin densities on other carbon atoms. Illustrative calculations for the cases of triphenylmethyl and perinaphthenyl are described.
Vibrational Spectra of OsF6 and PtF6
Authors: Weinstock Bernard , Claassen Howard H. , Malm John G.
Published: January 2005

Infrared absorption spectra of gaseous OsF6 and PtF6 from 6–50μ and the Raman spectrum of liquid OsF6 are reported. These are interpreted in terms of the octahedral point group Oh, and the six fundamental frequencies are determined. Their values and symmetry species are for OsF6 733 (a1g), 632 (eg), 720 (f1u), 268 (f1u), 252 (f2g), and 230 (f2u); for PtF6 655 (a1g), 601 (eg), 705 (f1u), 273 (f1u), 242 (f2g), and 211 (f2u). Thermodynamic functions, including electronic contributions, are calculated for the ideal gaseous state of both compounds.

A comparison of the details of the vibrational spectra of eleven hexafluorides reveals certain characteristic features for OsF6 and ReF6. Since only these two molecules have appropriately degenerate electronic ground states these differences are interpreted as evidence of a Jahn-Teller effect.
Elastic and Inelastic Scattering of Low-Velocity D+ and D2+ in Deuterium
Authors: Cramer W. H. , Marcus A. B.
Published: January 2005

Results are presented of the measurement in the energy range 4 to 400 ev of elastic and charge exchange cross sections for D+ and D2+ ions in D2. Ordinary ionization was not observed. Charge exchange was detected above 65 ev for D+ in D2 and over the entire range of energies for D2+ in D2. The present results are compared with measurements of collisions of hydrogen ions in H2.
Electron Spin Resonance Studies of Semiquinones and the C–F Bond
Authors: Anderson D. H. , Frank Peter J. , Gutowsky H. S.
Published: January 2005

The electron spin resonance spectrum has been observed for a solution of tetrafluoro p-benzosemiquinone and a value, aF=4.14±0.08 gauss, obtained for the fluorine hyperfine splitting. It is concluded that this splitting is caused by the σ—π configuration interaction proposed for protons attached to an aromatic free radical. The results show that the fluorine orbital in the C–F bond contains about 5% s character. The relationship between the hyperfine splitting constants and the contact contribution to the electron coupling of nuclear spins is commented upon. The electron spin density ρC at a carbon atom in an aromatic free radical is related to aF, for a fluorine bonded to the carbon, by the approximate relation aF≅−40ρC. Data are presented which can be explained by assuming the semiquinone free radicals produced by air oxidation of hydroquinones in alcoholic KOH dimerize or otherwise react in concentrated solution to give radicals with oxygen linkages, while dibenzosemiquinone radicals are produced from quinones under reducing conditions. An X-band spectrometer was used; a brief description is given of it and of an electronic sweep unit for the electromagnet.
Self-Diffusion in Liquid Argon
Authors: Cini-Castagnoli G. , Ricci F. P.
Published: January 2005

The self-diffusion coefficient of liquid argon has been measured by the capillary technique at 84.56±0.04 °K and at about 70 cm Hg. The average value of D(A37—A40) is (1.53±0.03) 10−5 cm2/sec.
Temperature Dependence of Raman Intensities
Authors: Chantry G. W.
Published: January 2005

The temperature dependence of the intensity of the Raman lines of a polyatomic molecule has been investigated. It is shown that, when account is taken of all possible ``hot'' band transitions as well as fundamental transitions, the temperature dependence of each band is the same as that found for the single band of a diatomic molecule. Degenerate vibrations are also considered and likewise shown to have the same temperature dependence.
Potential Energy Constants, Rotational Distortion Constants, and Thermodynamic Properties for NH3, ND3; PH3, PD3; AsH3, and AsD3
Authors: Sundaram S. , Suszek Frank , Cleveland Forrest F.
Published: January 2005

Normal coordinate analyses have been made for ammonia (NH3), phosphine (PH3), and arsine (AsH3) by the Wilson FG matrix method. Using the data on anharmonicities, and the corresponding completely deuterated molecules, the constants of the most general quadratic potential energy function have been obtained for all these molecules. Based on the technique of Kivelson and Wilson, the rotational distortion constants of all the 6 molecules have been determined and compared with the results obtained from previous rotational spectral data. The molar thermodynamic properties, heat content, free energy, entropy, and heat capacity also have been calculated for temperatures from 100 to 1000°K for the ideal gaseous state at 1 atmos pressure and for a rigid-rotor, harmonic-oscillator approximation.
Electron Spin Resonance of an Irradiated Single Crystal of Alanine: Second-Order Effects in Free Radical Resonances
Authors: Miyagawa Ichiro , Gordy Walter
Published: January 2005

The electron spin resonance of single crystals of l- and d-alanine has been observed at T=300°K and analyzed for different orientations of the crystal in the magnetic field and at several microwave frequencies ranging from 9 kMc/sec to 34 kMc/sec. The stable free radical produced by the irradiation is proved to be of the form CH3CHR, where R is a group which has no nuclei with detectable coupling. The hydrogens of the CH3 group of the radical are shown to have equivalent, isotropic coupling of 26 gauss each, essentially independent of the frequency of observation. This CH3 group coupling is interpreted as arising from s orbital spin density of the hydrogens, via hyperconjugation. The hydrogen of the CH group has both an isotropic, Fermi term, Af=20 gauss, arising from s orbital density on the hydrogen, and an anisotropic term Aμ=7 gauss arising from dipole-dipole interaction of the proton moment with the electron spin density, ρC, on the carbon. Although the signs of Af and Aμ could not be learned, they are shown to be of opposite sign. Hence the spin density is negative on either H or C. Principal values of the CH coupling are A1=7 gauss, A2=A3=27 gauss. The value of ρC is shown to be 0.80 approximately. For certain orientations of the crystal the CH coupling becomes equal to the CH3 coupling, and a quintet pattern is observed. Interesting second-order transitions are observed which for the [001] orientation become in the region of 24 kMc/sec as strong as the normal first-order transitions. A general theory is developed which accounts satisfactorily for these second-order effects which are probably of consequence in the electron spin resonance patterns of numerous other free radicals trapped within solids.
NMR Study of Bonding in Some Solid Boron Compounds
Authors: Silver A. H. , Bray P. J.
Published: January 2005

Nuclear magnetic resonance studies of B11 have been performed in powder samples of some metal borides, boron-nitrogen compounds, borofluorides and borohydrides, and borates. The B11 nuclear electrical quadrupole interactions have been measured and used in the Townes and Dailey approach to estimate the probable bonding electron configurations.