bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature-Dependent Bismuth-Cesium Photosurfaces
Authors: Zollweg R. J. , Taylor C. R.
Published: April 2005

The yield of bismuth-cesium photosurfaces is sometimes strongly temperature dependent. We have investigated this effect and found it to be dependent upon the presence of oxygen and upon the size of the aggregates making up the photosurface. The photoelectron energy spectra are also examined. It is concluded that the temperature dependence probably arises from a change in escape depth with temperature because of phonon collisions, but that the principal photoelectron energy loss may occur at oxygen impurity sites.
Nonohmic Behavior in Near-Stoichiometric Rutile (TiO2)
Authors: Greener E. H. , Whitmore D. H.
Published: April 2005

Experimental observations of the isothermal current-voltage relationships in rutile (TiO2) over the temperature range 632°–908°C have shown that currents in excess of ohmic currents can be drawn through small, single crystals of near-stoichiometric composition. These currents have been identified as space-charge-limited currents analogous to those observed in the case of a vacuum diode. An increase in the ambient specimen temperature had the effect of displacing the potential for transition from ohmic to non-ohmic behavior to greater values so that, at 908°C, near-stoichiometric rutile exhibited only ohmic currents even at the largest fields employed.
Growth of Single-Crystal Calcium Fluoride with Rare-Earth Impurities
Authors: Guggenheim H.
Published: April 2005

The preparation of large single crystals of CaF2 by the zone melting and the pulling techniques is reported. Many crystals were doped with rare-earth elements. The ingots showed high optical perfection; they could be used in optical maser studies. The annealing of such crystals is discussed.
Perfection of the Lattice of Dislocation-Free Silicon, Studied by the Lattice-Constant and Density Method
Authors: Straumanis M. E. , Borgeaud P. , James W. J.
Published: April 2005

The lattice-constant and density method revealed that a high-purity silicon crystal free of dislocations has a perfect lattice without an excess of vacant sites or interstitials (n′=8.00004) within the limits of error, in agreement with the results obtained with the decoration method. The lattice constant of vacuum heated silicon powder of semiconductor purity was 5.43070±0.00004 A; that of the nonheat-treated powder was 5.43081 A at 25°C. The constants determined from crystal chips by the rotating crystal method were lower: between 5.43028–5.43048 A at 25°C. As the constants of each series of measurements could be reproduced very well (s=±0.00004 A), the lower values suggested the presence of some unknown systematic errors, the magnitude of which is outside the scope of errors due to absorption. The thermal expansion coefficients of all samples between 10°–60°C were (2.6±0.4)×10−6/°C. The average density of etched crystal chips was 2.3289±0.0001 g/cm3. The lower density of the nonetched chips indicated the presence of microcracks, removable by etching, within the distorted surface layers. There was no significant difference in density of bars sawed, or of chips broken from the crystal and etched.
Texture Transition in High-Purity Silver and Its Correlation with Stacking Fault Frequency
Authors: Hu Hsun , Cline R. S. , Goodman S. R.
Published: April 2005

The rolling texture of high-purity silver is found to change gradually from the common silver type to the copper type as the temperature of deformation increases. The transition is completed in the temperature range 150°–200°C. There is a general correlation between the texture transition and the change in stacking fault frequency as a function of rolling temperature. On the basis of such a correlation, the texture transition produced by varying the temperature of deformation, or by alloy additions, can be consistently interpreted in terms of a change in the stacking fault energy, a change in the dislocation density, or both.
The Ionic Character of Diatomic Molecules
Authors: Dailey B. P. , Townes C. H.
Published: April 2005

A relation between the electronegativity difference of two bonded atoms and the ionic character of the bond is obtained for singly bonded diatomic molecules in the gaseous state. The relation is based primarily on the wide variety of nuclear quadrupole coupling constants recently measured by microwave techniques. However, dipole moments of diatomic molecules are also used and discussed. Both quadrupole coupling constants and dipole moments indicate strongly that bonds involving electronegativity differences greater than 2 are almost completely ionic. Certain effects of hybridization, overlap, and polarization on considerations of ionicity are discussed.
Structure and Barrier Height of Methyl Mercaptan from Microwave Data
Authors: Solimene N. , Dailey B. P.
Published: April 2005

The 000—101 rotational transitions of several isotopic species of methyl mercaptan have been observed. This has permitted a complete determination of the structural parameters of this molecule. The torsional energy levels of C12H3S32H and C12D3S32H have been approximately determined by relative intensity measurements. A sinusoidal barrier height has been determined which gives torsional energy levels in agreement with the observed ones.
Photoconductivity and Crystal Imperfections in Cadmium Sulfide Crystals. Part I. Effect of Impurities
Authors: Bube Richard H. , Thomsen S. Milton
Published: April 2005

The conductivity and photosensitivity of cadmium sulfide crystals can be controlled by the incorporation of suitable impurities. The conductivity and photosensitivity are increased by the incorporation of a halide or a trivalent cation, and decreased by the incorporation of copper or silver. A possible mechanism by which such impurities may produce the observed effects on the photoconductivity is presented.
Irradiation of Ferrous Ammonium Sulfate Solutions: Energy Absorption and Ionization Calculations for Cobalt-60 and Betatron Radiation
Authors: Cormack D. V. , Hummel R. W. , Johns H. E. , Spinks J. W. T.
Published: April 2005

G values for the irradiation of ferrous ammonium sulfate by cobalt-60 and betatron radiation have been recalculated taking into account wall effects which were neglected in the original paper.
Shape of the Coexistence Curve near the Critical Temperature
Authors: Rice O. K.
Published: April 2005

It is shown that diffusion in the gravitational field in binary liquid systems is so slow that the effect of gravity may be completely neglected in studies of the coexistence curve. The data arising from the direct measurement of the coexistence curve of the cyclohexane-aniline system have been correlated with those from measurements of the densities of coexisting phases. A graph has been constructed which confirms the earlier conclusion that the coexistence curve is flatter at the top than can be accounted for by a cubic relation between temperature and density. Finally, a discussion is given of the liquid-vapor equilibrium in a one-component system. It is pointed out that the range of densities over which the meniscus has been reported to disappear within the tube in earlier work is so small that measurements of the coexistence curve need to be made with a temperature control of the order of 0.0001°. Only the recent work of Lorentzen on carbon dioxide meets this requirement. His data appear to be favorable to the idea that there is a short flat portion on the top of the coexistence curve, but are still not quite adequate to settle the question.
Relation between Isotherms and Coexistence Curve in the Critical Region
Authors: Rice O. K.
Published: April 2005

A general relation has been given relating the slope of the isotherms along the liquid-vapor coexistence curve to the shape of the latter, and has been applied to the case where the coexistence curve is rounded on the top and to the case where it has a flat horizontal portion. If the coexistence curve has the form T—Tc = — a|ρc—ρ|n (where T = temperature, ρ=density, subscript c indicates a value at the critical point, and a and n are constants) it can be shown that the critical isotherm is given by P−Pc=a(∂2P/∂T∂ρ)c(ρ−ρc)|ρ−ρc|n,provided (∂2P/∂T∂ρ)c is finite. This equation should hold over the region where ∂2P/∂T∂ρ is approximately constant. If there is a flat, horizontal portion at the top of the isotherm a similar equation will be approximately true under the same conditions beyond the flat portion. The actual shape of experimental isotherms in the critical region is considered. ∂2P/∂T∂ρ is approximately constant only over a limited range of densities, and beyond this range the slopes of the isotherms become greater than indicated by the equation; however, general orders of magnitude are as expected. It is not possible to decide definitely from the data considered whether the critical isotherm has a horizontal region over a finite range of densities. Finally, a discussion is given of the discontinuities of thermodynamic quantities, particularly Cv, as one passes from the one-phase to the two-phase region. It is shown that Cv must be much larger in the two-phase than in the one-phase region.
Overlaps of Trial Functions for the Hydrogen Molecule. II. Covalent and Ionic Character of H2
Authors: Braunstein Jerry , Simpson William T.
Published: April 2005

The mutual overlaps of some of the trial functions for the hydrogen molecule are presented and their relation to the covalent and ionic character of the bond are discussed. Difficulties involved in the definition of covalent and ionic as orthogonal components of wave functions are pointed out and contour maps indicating the shapes of some of the functions discussed are given.
Vibrational Intensities. IV. Bond Moments in C2F6
Authors: Williams Dale G. , Person Willis B. , Crawford Bryce
Published: April 2005

The intensities of four of the infrared-active fundamentals of C2F6 have been determined and interpreted in terms of the bond-moment hypothesis. The bond-moment parameters are overdetermined so that an internal check is provided. This check, supplemented by comparison with data on related molecules, shows that the bond-moment picture is a useful approximation but that it is not quantitatively reliable.
Properties of the Hydrogen Bond. The Role of Lone Pair Electrons
Authors: Schneider W. G.
Published: April 2005

The properties of the hydrogen bond are discussed in relation to the equivalent orbital representation of lone pair electrons. The dependence of the energy of the hydrogen bond on the nature of the hybridized lone pair orbital is pointed out. On the basis of point charge models for the water and hydrogen fluoride molecules, and on the basis of a consideration of known hydrogen-bonded structures, evidence is presented to show that the directional properties of the hydrogen bond are determined largely by the directional properties of the lone pair orbital, and that the strongest bonds result when the hydrogen bond direction is collinear with the lone pair orbital direction.
An Explicit Derivation for the s Vectors in the Normal Coordinate Treatment of Molecular Vibrations
Authors: Malhiot Robert J. , Ferigle Salvador M.
Published: April 2005

The equations Σn sni=0 and Σn rn0×sni=0, together with the gradient properties are used to derive the s vectors for the four principal types of internal motion of a polyatomic molecule.
Forces between Unlike Molecules and the Properties of Gaseous Mixtures
Authors: Mason Edward A.
Published: April 2005

The intermolecular potentials for a number of pairs of unlike molecules have been calculated from the known potentials for pairs of like molecules, by means of semi-empirical combination rules. The intermolecular potential used was of the exp-six form, [open phi](r)=ε/(1−6/α)[(6/α)eα(1−r/rm)−(rm/r)6]. The validity of the combination rules were tested by calculating a number of properties of binary gas mixtures for comparison with experimental values. The resulting agreement was quite reasonable, and it was concluded that the combination rules can be used with some confidence.
Thermoelectric Behavior of Nickel Oxide
Authors: Parravano G.
Published: April 2005

Measurements have been made on the thermoelectric power of several nickel oxide samples containing foreign ions. Using an energy model recently proposed for nickel oxide, the effect of the nature and concentration of additions on the Fermi level, hole concentration, and mobility is derived and discussed. For most of the samples hole concentration can be related to chemical composition. A case of change in valence of the addition induced upon introduction into the matrix is found. The use of the thermoelectric effect to determine impurity in nickel oxide is discussed. The energy scheme of nickel oxide which emerges from this work and that of Morin is emphasized as a drastic departure from the classical model of an electrical semiconductor.
Dielectric Properties of Liquid Butyl Alcohols
Authors: Dannhauser Walter , Cole Robert H.
Published: April 2005

Measurements of static dielectric constant were made for all except t-butyl alcohol from the boiling points to —140°C; dispersion and loss were measured below 0°C in the range 20 cy/sec to 2 Mc/sec. Multiple dispersions were found as in other alcohols. The temperature dependences of static values are examined in terms of finite extent of chainwise molecular coordination by hydrogen bonding, and the rate laws of the dispersions are discussed.
Pi-Electron Forces between Conjugated Double Bond Molecules
Authors: Haugh Eugene F. , Hirschfelder Joseph O.
Published: April 2005

The long-range forces between large conjugated double bond molecules are highly directional and anomalously strong. This is the result of pi electrons moving freely from one end of the conjugated double bond system to the other, making the molecule behave like an extended oscillator. All three types of dispersion forces: σσ, σπ, and ππ are calculated for ethylene, acetylene, and the higher polyenes. In addition the ππ interaction energy is calculated for benzene. The free electron molecular orbitals are used for the π electrons and products of these orbitals are approximated by ``transition monopoles.'' Our treatment of the σ electrons and the use of the transition monopoles were suggested by London. The resulting energies are easy to calculate and easy to interpret. The ππ energy is proportional to the square of the energy of interaction of two real transition dipoles (real in the sense of the monopoles being separated by a finite distance). Previously, Coulson and Davies calculated the ππ interaction energy using LCAO orbitals and evaluating all integrals accurately; however, because of the complicated nature of their calculations it was not possible for them to obtain a simple understanding of the variation of the energy with the orientations of the molecules. The values we obtain for the ππ energy agree with those of Coulson and Davies except for a scale factor, our results being uniformly 35 smaller. Such a scale factor corresponds to an adjustable parameter in either the Coulson and Davies treatment or ours. The σπ interaction energy has never previously been considered. For long polyenes, for which a simplified treatment is given, the ππ energy is larger than the σπ which is larger than that of the σσ. In the appendix, the free-electron model is used to calculate the pi-electron contribution to the polarizability and excellent agreement is obtained with the LCAO calculations of Davies.
Band Widths in the Spectra of Manganous and Other Transition-Metal Complexes
Authors: Orgel L. E.
Published: April 2005

The spectrum of the hydrated manganous ion is interpreted in detail and the factors influencing the widths of the bands are deduced. The band widths in other transition-metal spectra are shown to be explicable in the same way.
Prediction of Madelung Constants
Authors: Templeton David H.
Published: April 2005

Madelung constants of both simple and complex salts can be reduced to a common scale by taking the nearest-neighbor distance as the unit distance and then dividing by half the sum of the squares of the charges of all the atoms in the stoichiometric unit. These ``reduced Madelung constants,'' α, can be predicted within a few percent by the relation α=1.89—1/m, where m is the harmonic mean coordination number. Madelung constants have been calculated for LaOCl, YOF, ReO3, and several perovskite structures for comparison with the predictions.
Some Applications in Physics of the P Function
Authors: Masters Joseph I.
Published: April 2005

The mathematical background and typical applications in physics are presented for a recently tabulated function. Because of its properties, the P function should prove to be a useful aid in the solution of certain problems in applied mathematics involving surface integrations in cylindrical coordinates. A tabulation of the function in its normalized form is appended. Particular attention is paid to the application of the P function to multiple scattering problems involving circular symmetry.
dc Resistivity in the Nickel and Nickel Zinc Ferrite System
Authors: Van Uitert L. G.
Published: April 2005

The dependence of the resistivities of nickel and nickel zinc ferrites prepared from high purity reagents upon composition and firing temperature has been studied.

It has been determined that iron deficient nickel zinc ferrites are of much higher resistivity than iron deficient nickel or zinc ferrites.

The iron deficient ferrites prepared, which were fired in oxygen below 1300°C and have Ni:Zn ratios greater than 3:7, show a positive thermoelectric voltage. Other compositions or materials fired above 1300°C have a negative thermoelectric voltage.

The effect of excess iron upon resistivity is dependent upon the presence or absence of zinc at temperatures below 1300°C.
High-Temperature Equation of State by a Perturbation Method. II. Polar Gases
Authors: Zwanzig Robert W.
Published: April 2005

The perturbation theory described in a previous article is applied to the calculation of the equation of state at high temperature of a polar gas. The electrostatic dipolar potential is considered to be a perturbation on the nonpolar Lennard-Jones potential. The dipole contribution to the equation of state is expressed in terms of properties of the unperturbed system. These properties are obtained from experimental data on argon and xenon. Numerical tables of the reduced equation of state of the polar gas, over a wide temperature and density range, are presented. The theory is tested on water vapor and on methyl fluoride. Theoretical predictions of the pressure agree with experimental data over a wide density range (up to 0.25 g/cc for water) to within several percent.
New Form of Molecular Potential Function for Use in Molecular Vibrational Analysis
Authors: Slowinski Emil J.
Published: April 2005

A molecular potential function which takes simple and direct account of intramolecular strains is proposed. The parameters in the function are the conventional bond-stretching and angle-bending force constants and the strain-free magnitudes of the bond lengths and bond angles.

The function is applied to the analysis of the vibrations of XY2 molecules with C2v symmetry. Calculations based on the zero-order frequencies of H2O and D2O indicate that a three-parameter function is adequate for these molecules. All molecules studied with the function show a moderate attraction between the end atoms of the molecules, resulting in a decrease in the size of the bond angle from the strain-free value. For compounds of the oxygen family with hydrogen the bond angle at zero strain appears to have a constant value equal to 120°.
Theory of the Faradaic Admittance. III. Application of Diffusion Theory to Current-Interrupter Studies
Authors: Scott William T.
Published: April 2005

The problem of predicting and interpreting the potential vs time curves obtained in current-interrupter studies of electrochemical reactions is considered with reference to those cases in which diffusion in one or both phases plays a major role. Fick's laws of diffusion are solved in such a way as to provide a complete set of equations governing the current and potential across the interface and the concentrations of the active substances at the interface. These solutions are given for a plane, finite or effectively infinite, unstirred or boundary layer in which diffusion takes place, and for initially uniform or arbitrary gradients. Application is made to the case of a simple uncomplicated reaction and to the hydrogen discharge case, and the mathematical complexity of the latter is made evident. Some efforts are made to discuss the solution of the potential-time equation, and a procedure is given in the simpler case for evaluating the parameters of the process from experimental data. A mathematical appendix gives the application of the Laplace transform method to the solving of Fick's laws under transient conditions and to related aspects of the problem.
Heat Capacity of Zinc Fluoride from 11 to 300°K. Thermodynamic Functions of Zinc Fluoride. Entropy and Heat Capacity Associated with the Antiferromagnetic Ordering of Manganous Fluoride, Ferrous Fluoride, Cobaltous Fluoride, and Nickelous Fluoride
Authors: Stout J. W. , Catalano Edward
Published: April 2005

The heat capacity of ZnF2 has been measured calorimetrically between 11 and 300°K. In addition to the direct experimental data, values of heat capacity, entropy, enthalpy, and free energy are tabulated at selected temperatures. The values of entropy, and enthalpy at 298.16°K are S0=17.61±0.03 cal deg—1 mole—1 and H0–H00=2827±5 cal mole—1. The heat capacity of ZnF2 has been used, with a corresponding states argument, to estimate the lattice contributions to the entropy and heat capacity of the isomorphous fluorides MnF2, FeF2, CoF2, and NiF2 which exhibit heat capacity maxima associated with antiferromagnetic ordering at 66.5, 78.35, 37.70, and 73.22°K, respectively. The values of electronic entropy at the maximum in heat capacity are: MnF2, 0.85R ln6; FeF2, 0.87R ln5; CoF2, 0.80R ln2; NiF2, 0.71R ln3. The electronic entropies and heat capacities are compared with molecular field and spin wave theories of antiferromagnetism. At very low temperatures the electronic heat capacity on NiF2 is varying approximately as T32; whereas that of the other antiferromagnetic fluorides depends much more strongly on temperature. This behavior of the electronic heat capacity of NiF2 is believed to be associated with the small ferromagnetic moment found in magnetic anisotropy measurements on this salt.
Thermodynamics of a Fluid Substance in the Electrostatic Field
Authors: Frank Henry S.
Published: April 2005

An ``apparatus'' is described in which, in a thought experiment, the whole of a sample of fluid may be subjected to a uniform electrostatic field under controlled conditions. The work done in such a process can be written into fundamental thermodynamic equations so as to enable the field strength E to be a variable of state in a way which is essentially symmetrical with the way in which P and T are variables of state. This enables a variety of differential coefficients to be obtained, some of which appear to be new. A discussion is given of the relationship between ``electrostriction pressure'' (as derived in electrostatics) and thermodynamic pressure. Application of the formalism to systems of more than one component is illustrated by discussion of the change in composition produced by charging the plates of a small condenser immersed in a large volume of binary fluid mixture. The customary representation of the ``energy density'' in a field as equal to E2K/8π is discussed, and found to be limited in formal validity when the field is nonuniform, when the charging process takes place under conditions which do not hold the volume constant, or when dielectric saturation is taken into account.
Microwave Spectrum and Molecular Structure of Methylchloroacetylene
Authors: Costain C. C.
Published: April 2005

The J = 6←5 rotational transitions have been observed for 10 isotopic species of CH3CCCl, including four of the fully deuterated molecule. The values for DJ were calculated from the force constants of the molecule, and are tabulated with the resulting values for B0. The structural parameters giving the best fit to the 10 moments of inertia IB are: r0(C–Cl) = 1.6371 A, r0(C≡C) = 1.2069 A, r0(C–C) = 1.4584 A, r0(C–H) = 1.117 A, ≰HCC = 110° 46′, r0(C–D) = 1.114 A, and ≰DCC = 110° 30′. The quadrupole coupling constant eqQ was determined as —79.6 Mc/sec for Cl35 and —62.6 Mc/sec for Cl37. For CH3CCCl35, CH3CCCl37, CD3CCCl35, and CD3CCCl37 experimental values of DJK and HJKK were determined from the K structure. To fit the observed fine structure it was necessary to include the third-order term HJKK in the expression for the rotational energy.
Equation of State of Gases by Shock Wave Measurements. II. The Dissociation Energy of Nitrogen
Authors: Christian R. H. , Duff R. E. , Yarger F. L.
Published: April 2005

The results of equation of state measurements made behind strong shock waves in nitrogen are consistent only with the higher of the two spectroscopically acceptable values of the dissociation energy of nitrogen, 9.764 ev.
Absorption Spectrum and Quantum States of the Praseodymium Ion. I. Single Crystals of Praseodymium Chloride
Authors: Sayre Edward V. , Sancier Kenneth M. , Freed Simon
Published: April 2005

The structure of the polarization spectra exhibited by single crystals of anhydrous praseodymium chloride permitted the assignment of quantum states of the praseodymium ion because of the fact that the symmetry of the crystal fields had previously been determined by x-rays. The crystals which were diluted with isomorphic, colorless lanthanum chloride, were grown from melts.

Observations of transitions over the range from 2200 A to 18 000 A at the temperatures of liquid nitrogen and liquid helium led to the identification of seven upper states as well as the substates into which they were split by the crystal fields. The four lowest substates of the ground state also were characterized. The F triplet was found inverted.

All the transitions were forced electric dipole in nature.
Absorption Spectrum and Quantum States of the Praseodymium Ion. II. Anhydrous Praseodymium Fluoride in Films
Authors: Sayre Edward V. , Freed Simon
Published: April 2005

The absorption spectra of anhydrous praseodymium fluoride were examined to confirm term designations derived from the spectra of anhydrous praseodymium chloride. In the fluoride, praseodymium ion is at the center of a micro-field of C2V symmetry and in the chloride it is in a field of C3h symmetry. There was complete consistency in the interpretations of the spectra of the two compounds.

A new phenomenon appeared in the spectrum of the fluoride, however. The selection rules prohibiting some of the possible transitions of an ion in a field of C2V symmetry valid at the temperature of liquid nitrogen were lifted at the temperature of liquid helium, where in fact all possible transitions occurred. There is evidence against any gross crystallographic transformation.

It is surmised that the positions of energy minimum for the ions lie slightly off the symmetric positions possibly due to higher order interactions such as occurs in the case of barium titanate.
Spectrum of Carbon Monoxide-Oxygen Explosion. I. The Visible Spectrum
Authors: Knipe R. H. , Gordon Alvin S.
Published: April 2005

The effect of composition on the spectrum of the explosion of pure, dry CO and oxygen has been studied. In addition to the expected continuum with a superposed banded emission, a banded absorption has been observed. The absorber is probably the a(3Πr) state of CO. The possibility that this excited state of CO is important in the production of the continuum is discussed.
Resolution of ν11(E) of Allene at 28μ
Authors: Rao K. Narahari , Palik E. D.
Published: April 2005

The perpendicular band of allene at 28μ(ν11) has been resolved for the first time. The average separation between successive Q branches, which represents essentially 2[Aν′(1—ζν)—Bν′]ν=11 is found to be 1.2±0.2 cm—1.
Infrared and Raman Spectra of Dicyanoacetylene. II
Authors: Miller Foil A. , Hannan Roy B. , Cousins Lauren R.
Published: April 2005

The infrared spectrum of dicyanoacetylene has been extended downward to 320 K, and one more combination tone located. Fifteen Raman frequencies have now been observed in place of the four reported earlier, allowing the vibrational assignments to be revised and extended. All but one of the fundamentals have now been observed directly, and that one (107 K) is well established from combination tones. The totally symmetric fundamentals have been reassigned to 2290, 2119, and 692 K.
Nature of the Hydrogen Bond. II. The Effect of Hydrogen Bonding and Other Solute-Solvent Interactions upon the Shape and Intensity of the Infrared OH Band of Phenol
Authors: Tsubomura Hiroshi
Published: April 2005

The hydrogen-bonded OH bands of phenol are studied in ternary systems, each of which is composed of phenol, a proton acceptor, and a solvent. The acceptors used are ethyl ether, ethyl acetate, acetonitrile, and hexamethylene tetramine. It is confirmed that the frequency, shape, and molecular extinction coefficient of the band are not changed by the concentration of the acceptor, as far as the latter is smaller than ca 2 mole/liter. The spectra are slightly modified by further increase of the concentration of the acceptor. These modifications are in all cases far smaller than the modification due to the hydrogen bonding, and the peak intensities remain nearly constant. The equilibrium constants for the formation of the hydrogen bond are determined for all acceptors and the heat of formation is determined for the case of hexamethylene tetramine. It is found that the decrease of frequencies of the hydrogen-bonded OH bands is not strictly parallel to the increase of equilibrium constants.
Mass Spectrometric Study of Barium Oxide Vapor
Authors: Inghram Mark G. , Chupka William A. , Porter Richard F.
Published: April 2005

Ions formed by electron bombardment of the vapor in thermodynamic equilibrium with BaO solid have been studied mass spectrometrically. The BaO solid was heated in a Knudsen cell and a sample of the effusing vapor entered the ion source of a mass spectrometer. At cell temperatures between 1500°K and 1800°K, ion currents of Ba+, BaO+, Ba2O+, Ba2O2+, and Ba2O3+ were observed. The variations of ion intensities with temperature were measured and appearance potential curves were obtained. Possible mechanisms of ion formation were considered, and evidence for the existence of gaseous molecular species of BaO, Ba2O, Ba2O2, and Ba2O3 was obtained. The major molecular species, effusing from the Knudsen cell, was BaO. A thermodynamic treatment of ion currents yields the following heats of reaction BaO(s)=BaO(g);           ΔH0∘=104±4 kcal/moleBaO(g)=Ba(g)+O(g);      ΔH0∘=130±5 kcal/moleBa2O2(g)=2BaO(g);        ΔH1700∘=89±11 kcalBa2O(g)=Ba(g)+BaO(g);  ΔH1700∘=93±17 kcal.
Thermodynamic Properties of Krypton Adsorbed on Titanium Dioxide (Rutile)
Authors: Pace E. L. , Dennis Kent S. , Berg W. T.
Published: April 2005

The zero point entropy of krypton adsorbed on titanium dioxide (rutile) has been determined at a coverage of 0.57 of the monolayer capacity from calorimetric measurements of the heat capacity, differential heat of adsorption, and from adsorption isotherms. The value is 0.4 cal deg—1mole—1 with an experimental uncertainty of the order of ±0.8 cal deg—1mole—1. Within this high uncertainty, the result is in essential agreement with the results of Morrison and co-workers for argon adsorbed on rutile and Aston and co-workers with neon adsorbed on rutile.
Near Infrared Spectrum of Liquid Diborane
Authors: Beachell Harold C. , Levy Eugene J.
Published: April 2005

The infrared spectrum of liquid diborane has been obtained between 4500—10 500 cm—1. A complete assignment for the observed overtone and combination bands is presented.
Use of Interpolation Theory in the Analysis of Gas Adsorption Isotherms. II. Estimation of Certain Parameters
Authors: Honig J. M. , Rosenbloom P. C.
Published: April 2005

In an extension of the interpolation theory described elsewhere, upper and lower bounds have been placed on a number of physical quantities of interest in adsorption theory.
Dielectric Dispersion of Rochelle Salt in the Microwave Region
Authors: Akao Humio , Sasaki Taizo
Published: April 2005

The dielectric dispersion of rochelle salt was measured at 3000∼20 000 Mc/sec using a new method. In this method ε′ and ε″ is obtained by measuring the half-power point and the shift of resonant frequency of a rectangular TE01 mode cavity.

These results show that the relaxation frequency of rochelle salt exists in the decimeter wave region.
Motions of Molecules in Condensed Systems. IX. Infrared Absorption Anisotropy and Induced Molecular Motion in a Single Crystal of Benzene
Authors: Zwerdling Solomon , Halford Ralph S.
Published: April 2005

Infrared absorption spectra were observed with radiation polarized linearly along each of the two extinction axes contained in a thin cross section from a single crystal of benzene grown especially for this purpose. The spectra indicate consistently that the cross section was the 010 plane, that they record separately the absorptions polarized along the a-axis and the c-axis, respectively. The anisotropies of the induced absorptions exhibited by five fundamental molecular vibrations (ones that appear only in spectra for condensed phases) are all quite similar and may even be identical. It thus appears that the induced motions, super-imposed upon the several intrinsic ones by the perturbing intermolecular interactions, have a property of similarity independent of the differing natures of the intrinsic motions that are being perturbed.
Theory of Internal Over-All Rotational Interactions. II. Hamiltonian for the Nonrigid Internal Rotor
Authors: Kivelson Daniel
Published: April 2005

An approximate Hamiltonian for a nonrigid internal rotor has been derived. The potential energy has been expanded in a Taylor's series in the displacement coordinates and in a Fourier series in the angle of internal rotation Θ. The Hamiltonian was transformed by a contact transformation, and a second-order Hamiltonian in which vibrations and rotations have been separated has been obtained. The Hamiltonian consists of terms which constitute the usual rigid internal rotational problem, of centrifugal distortion terms involving both over-all and internal angular momentum, and of terms that arise because of the repulsive nature of the barrier. These repulsive terms enter as a single term, 2JFv(m|1 — cos3Θ|m), in the expression for the rotational transitions of symmetric rotors, where J is the total angular momentum quantum number and m is the pseudo-quantum number for internal rotation. The repulsive constant, Fv, is given by the relation Fv=−Σ12[Bxx(i)+Byy(i)]ai(1),where Bxx(i)+Byy(i) is the derivative of the rigid rotor rotational constant with respect to the ith symmetry coordinate, and ai(1) is one-half the displacement of the equilibrium position of the ith internal coordinate in going from Θ=0 to Θ=π/3.

The dependence of the barrier height upon the vibrational motion has also been studied.
Theory of Internal Over-All Rotational Interactions. III. Nonrigid Asymmetric Rotors
Authors: Kivelson Daniel
Published: April 2005

The theory of the interactions of hindered internal rotation with over-all rotations is extended to include nonrigid asymmetric rotors. The interdependence of hindered internal rotation and vibrations and their effect upon the vibrational energy levels is considered. The theory is developed analogously to the theory developed for symmetric rotors in a previous paper. An approximate over-all internal rotational wave function of the form 1/(2π)½ exp[i(PzIz2/Iz —τ)]φr is discussed, where φr is the wave function that diagonalizes the rigid rotor Hamiltonian and τ is an integer.

While the general energy relation involves too many parameters to compute or to fit empirically, certain special cases are discussed. In particular for the 000→101 transition of the CH3NO2 type of molecule one has ν(000→101)=(101|〈H〉R|101)[1+F1(m|1−cos3θ|m)+G2(m|Π2|m)]+2G3(m|Π2|m)+2F2(m|1−cos3θ|m), where (101|〈H〉R|101) is the rigid rotor energy for the 101 level, Θ is the angle of internal rotation, II is the internal angular momentum, m indicates a given internal rotational level, and the F's and G's are constants which can be evaluated from a knowledge of the vibrational characteristics of the molecule and of the forces that constitute the hindering barrier to internal rotation.
Scattering of High Velocity Neutral Particles. VI. Krypton-Krypton
Authors: Amdur I. , Mason E. A.
Published: April 2005

Total collision cross sections have been measured for krypton atoms with energies between 700 and 2100 ev, scattered in room temperature krypton, to obtain potential energy information for the interaction of two krypton atoms. The potential function may be represented by V(r)=2.55×10−10/r5.42 ergsfor r between 2.42 A and 3.14 A.

The present potential appears to be consistent with potentials, valid at larger separation distances, which have been derived from measurements of gaseous compressibility, transport, and crystal properties, within the limits of uncertainty of these larger distances potentials.
Bonding in the Zinc Family Metals
Authors: Wallace W. E.
Published: April 2005

Attention is directed to the very large departures of the structures of the zinc family (IIb) metals from those produced by the close packing of spheres. This seems to indicate that cohesion in these metals differs considerably from the normal nondirectional metallic bonding. It is proposed that there is a system of covalent bonds in the basal plane resulting from bonding orbitals which are hybrids of one of the d and two of the p atomic orbitals. These absorb some of the s electrons and leave only 1.33 electrons/atom in the s band. Support for the proposed bonding scheme is provided by showing that with it one can account for many otherwise puzzling properties of the IIb metals and their alloys. The properties which are discussed in terms of the proposed scheme are (1) the abnormally large axial ratios in zinc and cadmium, (2) the effect of temperature on the axial ratios of these metals and the alloys of magnesium and cadmium, (3) the effect of alloying on the axial ratio, (4) the dependence of the axial ratio on the degree of order in MgCd3, (5) the great abundance of Schottky defects in certain magnesium-cadmium alloys, (6) the asymmetry of the heats of alloying of magnesium and cadmium, (7) the structure of solid mercury, (8) electrical conductivities of the solids, (9) the positive Hall coefficient for zinc and cadmium, (10) the poor solvent power of these metals as solids, and (11) certain unusual features of the electrical conductivities of the liquid metals and the dilute amalgams.
Note on Theories of Time-Varying Space-Charge Polarization
Authors: Macdonald J. Ross
Published: April 2005

The nonlinearity of the differential equations governing space-charge buildup or decay cause the principle of superposition to be inapplicable. Thus, charging and discharging curves should differ and depend strongly on applied voltage when space-charge formation is appreciable. Two approximate theories of space-charge formation and decay are compared, and it is found that one of their main differences is that one has been partly linearized while the other has not. Finally, it is mentioned that of the several theories of the ac response of materials with space charge, only one has not been linearized; hence, it is the only one applicable for applied voltages above about kT/e.
Statistical Computation of Mean Dimensions of Macromolecules. III
Authors: Wall F. T. , Hiller L. A. , Atchison W. F.
Published: April 2005

Random walks subject to the excluded volume effect have been generated by means of a high-speed electronic digital computer for a number of different three-dimensional lattices and for one four-dimensional lattice. In contrast to results obtained for two-dimensional lattices discussed in an earlier article, the present results are compatible with the view that the ratio, 〈rn2〉Av/n, where 〈rn2〉Av is the mean square length of permissible walks of n steps, converges as n→ ∞ for three-dimensional and four-dimensional lattices. This conclusion is obtained through an analysis of an appropriate difference equation employing the methods developed earlier.

Convergence to a limiting value of the critical ratio mentioned above appears relatively rapid for the four-dimensional lattice investigated. Possible convergence for the three-dimensional lattices that have been investigated to date appears to be very slow. Thus, it appears that the limiting behavior will not be approached experimentally for values of n within the usual range of the degrees of polymerization of real polymer molecules.
Adsorption Studies on Clay Minerals. V. Montmorillonite-Cesium-Strontium at Several Temperatures
Authors: Gaines George L. , Thomas Henry C.
Published: April 2005

Ion-exchange equilibria for the pair cesium-strontium between aqueous chloride solutions and a montmorillonite clay have been studied in the temperature range 5°—75°. Data from chromatographic elution experiments have been found to be unreliable because of nonequilibrium effects, and a method independent of rate behavior has been applied. From the data obtained, equilibrium constants, solid-phase activity coefficients, heat content and entropy changes for the reaction have been evaluated.
Theory of One-Dimensional Fluid Binary Mixtures
Authors: Kikuchi Ryoichi
Published: April 2005

The rigorous solution of a one-dimensional fluid binary mixture with arbitrary interparticle potentials is obtained under the assumption that a particle interacts with its nearest neighbors, and that the system obeys classical statistical mechanics. This rigorous solution provides the interpretation of parameters used in the lattice model of binary mixtures.
Mass Spectrometric Investigation of Active Nitrogen
Authors: Jackson D. S. , Schiff H. I.
Published: April 2005

A small, central portion of an active nitrogen stream was continuously sampled into a mass spectrometer. The ratio of ion intensities at masses 14 to 28 was found to be higher than that for normal nitrogen at the same pressure. The ionization efficiency curves at mass 28, in the presence and in the absence of the discharge were superimposable, but those at mass 14 were quite different. The difference Δ14, between these two curves was plotted against the applied electron voltage. A discontinuity in this Δ14 curve showed that it resulted from two processes. The appearance potentials for these two processes were 14.72±0.26 ev and 16.1±0.3 ev. The lower value clearly indicated the presence of ground state atoms in active nitrogen. Several processes capable of producing the higher value are discussed. The concentration of active species is estimated to be between 0.1 and 1%.
Molecular Calculations. I. LCAO MO Self-Consistent Field Treatment of the Ground State of H2O
Authors: Ellison Frank O. , Shull Harrison
Published: April 2005

A theoretical study of the ground state of the water molecule utilizing the self-consistent field molecular orbital method in the linear-combination-of-atomic-orbitals approximation is reported. All 10 electrons have been explicitly included, and all integrals have been retained in the calculations. Results are listed for six different values of the bond angle from 90 to 180 degrees, but only for the experimentally observed OH distance. The effect of inner-shell outer-shell mixing is investigated and shown to have a significant effect upon the results. The electronic configuration is discussed both from the viewpoint of molecular and equivalent orbitals. The computed dipole moment is 1.51 D. The SCF ionization potentials agree well with the experimental values, their order of assignment being quite definitely established. The calculated total electronic energy is in error by about 0.75%. This energy changes by only 0.13% for a change in bond angle from 90° to 180°, however, and consequently, the treatment leads to an incorrect value for the equilibrium bond angle. The effect of configuration interaction is considered, and some investigation is made concerning the first excited electronic state.
Molecular Calculations. II. Methods of Approximation of Molecular Integrals
Authors: Ellison Frank O.
Published: April 2005

A description is given of the integral approximations used in the LCAO MO self-consistent field treatment of H2O reported in the preceding paper. The estimation of electronic repulsion integrals by replacing one of the electron charge distributions by a point charge is considered in detail and found to be reliable in certain general cases. A modification of the Sklar approximation is developed which is applicable to integrals involving 1saχb, in which μ(1sa) (effective Z) is small and μ(χb) is large. A method is described for securing a better ``corrected'' Mulliken approximation of exchange integrals. The estimation of unsymmetrical nuclear attraction integrals is carried out by using uniformly charged spheres of finite size to represent AO distributions. This method is compared with the Mulliken and Löwdin approximations.
Infrared Intensities in Liquid and Gas Phases
Authors: Polo S. R. , Wilson M. Kent
Published: April 2005

It is shown that Debye's and Onsager's theories of dielectric polarization lead to the same expression for the relation between the intensities of an infrared absorption band in the liquid and in the gas phases.
Shape of the Coexistence Curve in the Perfluoromethylcyclohexane-Carbon Tetrachloride System
Authors: Gopal Ram , Rice O. K.
Published: April 2005

Transition temperatures for the transition from the one-phase to the two-phase condition have been observed for the perfluoromethylcyclohexane-carbon tetrachloride system. It is found that (Tc—T+0.001°)⅓ (where Tc, which is equal to 28.623°, is the observed critical temperature) is a linear function of the molecular fraction of carbon tetrachloride. As is indicated by the form of this function there appears to be a flat horizontal portion at the top of the coexistence curve, which extends from 0.5375 to 0.5625 volume fraction CCl4. It involves such a small temperature range as to be almost unobservable and the flat top is much less marked than in the cyclohexane-aniline system.

The melting point of perfluoromethylcyclohexane has been found to be —41.72°C.
Infrared Studies of Naphthalene and Naphthalene-d8
Authors: Person Willis B. , Pimentel George C. , Schnepp Otto
Published: April 2005

Infrared spectroscopic studies of naphthalene and naphthalene-d8 are reported as follows: (a) far infrared studies of solid C10H8 in the region 450 to 130 cm—1, (b) studies of single crystals of C10H8 with polarized light in the spectral region 3500—450 cm—1 for the ab and bc planes at normal incidence, (c) study of gaseous C10H8 in the spectral region 1350—440 cm—1, (d) studies of single crystals of C10D8 with polarized light in the spectral region 3400—500 cm—1 for the ab plane at normal incidence, (e) study of a gaseous C10D8 in the spectral region 1000—700 cm—1. Most likely symmetry assignments for the absorptions of C10H8 and C10D8 are given and some of the bands of C10D8 are correlated with those of C10H8.
Vibrational Assignment and Thermodynamic Properties of Naphthalene
Authors: McClellan A. L. , Pimentel George C.
Published: April 2005

A complete vibrational assignment of naphthalene and naphthalene-d8 is presented. This assignment is in substantial agreement with the experimental thermodynamic properties, the product rule and the spectroscopic data. The assigned frequencies are used to calculate the thermodynamic properties of naphthalene, S0, Cp0, (H0—E00)/T, and — (F0—E00)/T from 273.16° to 1500°K.