bluuebunny/crossref_metadata_2025 huggingface dataset:
Neutron Diffraction Study of Gypsum, CaSO42H2O
Authors: Atoji Masao , Rundle R. E.
Published: January 2005

Using neutron diffraction data, the crystal structure of gypsum has been refined by Fourier and least squares methods. The hydrogen bond distance was found to be 2.82 A rather than 2.71 A, reported previously. The hydrogen positions are consistent with those obtained from nuclear magnetic resonance. The O–H distance is 0.99±0.03 A, and it appears that the O, H, O atoms are collinear. Infrared and Raman results are discussed in terms of the refined structure.
Thermal Motion in Ice and Heavy Ice
Authors: Zajac Alfred
Published: January 2005

Changes with temperature of x-ray intensities of the 00l reflections in ice and heavy ice are investigated. From these the amplitudes of thermal motion of oxygen and hydrogen atoms are determined separately. This can be accomplished since only hydrogen atoms contribute to the 004 reflection. The thermal amplitudes of the oxygen atoms, which represent molecular amplitudes, can be expressed in terms of a constant Debye characteristic temperature; 224°K for ordinary ice and 237°K for heavy ice. The amplitudes of thermal vibration of the hydrogen and deuterium atoms as derived from absolute intensities of 004 at various temperatures, cannot be expressed in terms of a characteristic temperature. They consist of superimposed stretching, bending and librational motions. In addition to these a rotational motion of low zero point energy seems to be present.
Reaction of Oxygen Atoms with Nitric Oxide
Authors: Harteck Paul , Reeves Robert R. , Mannella Gene
Published: January 2005

The rate of reaction of oxygen atoms with nitric oxide has been studied at several pressures (0.62, 0.85, 1.11 mm Hg) by measuring the relative intensities of the oxygen afterglow. The consumption of O atoms was observed as a three-body recombination (NO+O+M→NO2+M). At room temperature the reaction coefficient was found to be k2=7.6×10-32 cm6 molecules-2 sec-1, with an average deviation of 6.5%. The third body was mainly argon.
Effect of Anisotropy on Light Scattering by Streaming Freely Flexible Linear Macromolecules
Authors: Stevenson A. F. , Bhatnagar Hari L.
Published: January 2005

The theory of Peterlin, Heller, and Nakagaki is generalized to allow for each segment of the macromolecule possessing two different polarizabilities, one longitudinal and the other transverse. The polarization of the scattered light is then different from that given by the theory of PHN, which predicts the polarization to be that of ordinary Rayleigh scattering. Expressions for the four different differential cross sections which can be defined are derived.
Calculation of the Energies of Triatomic Hydrogen Using a Modified Roothaan Procedure
Authors: Meador Willard E.
Published: January 2005

Potential energies for some linear, symmetrical configurations of H3 have been calculated using a modified Roothaan procedure with configuration interaction, and including a variable shifting parameter. Calculations for two excited states are also given along with detailed discussions of the various energy functions. The results are found to be very close to those obtained by Hirschfelder, Eyring, and Rosen.
Expression in Terms of Molecular Distribution Functions for the Entropy Density in an Infinite System
Authors: Nettleton R. E. , Green M. S.
Published: January 2005

An expression for the entropy in a finite subvolume of an infinite fluid, originally proposed by Strato-novich on the basis of information theory, is rewritten in terms of functions related to the potentials of average force. The result exhibits a correction to the corresponding expression obtained by H. S. Green for a finite system, in the form of a series in powers of the concentration, of which the first terms have been investigated by Richardson. By neglect of correlations of three or more molecules and powers of the density higher than the third, the result is specialized to the case of a gas of low density, for which the configurational entropy per molecule is calculated with use of the radial distribution obtained by Kirkwood for hard-sphere and hard-core Lennard-Jones potentials.
Method for Growing Large CdS and ZnS Single Crystals
Authors: Greene L. C. , Reynolds D. C. , Czyzak S. J. , Baker W. M.
Published: January 2005

A new technique for growing single crystals of CdS and ZnS has been devised in which single crystals up to 115 g in weight are obtained. The conversion of sphalerite into wurtzite and vice versa is described. The growth mechanism of the single ZnS crystals is described and compared with that for CdS crystals previously reported.
Theory of Cold Crystallization of High Polymers
Authors: Wunderlich B.
Published: January 2005

The nonequilibrium limit of random crystallization of linear high polymers is described in this article. Expressions for crystallite size, surface area, crystallinity, and amorphous sequence distribution of crystallizable repeating units in random copolymers after cold crystallization are derived. Melting points and change of crystallinity with temperature in the melting range are discussed. All partially crystallized polymers are found to fall between the two limits of equilibrium and random (or cold) crystallization.

For the system poly(ethylene terephthalate-sebacate) enough data (ΔHu, Tmo, crystal structure, and Cp as a function of temperature and composition) are available, so that the cold crystallization limit could be calculated with help of an IBM 650 electronic calculator.
Matrix Isolation Studies: Possible Infrared Spectra of Isomeric Forms of Diazomethane and of Methylene, CH2
Authors: Milligan Dolphus E. , Pimentel George C.
Published: January 2005

The photolysis of diazomethane has been studied by the matrix isolation method. Argon and nitrogen matrices were used at 20°K. There is distinct infrared spectral evidence that unstable species have been detected spectroscopically: the production of stable products is inhibited until diffusion is permitted and a red glow accompanies diffusion. Among the identified products produced during diffusion are ethylene, propylene, methane, and polyethylene. The data suggest that methylene is present as well as a tautomeric structure of diazomethane. One of the absorptions observed at 1362 and 1114 cm—1 could be the bending mode of CH2.
The Influence of Internal Stress on the Structure of Electro-Deposits
Authors: Wyllie M. R. J.
Published: January 2005

The author's data on the properties of chromium electro-deposited from a standard chromic acid electrolyte are examined in the light of a theory first proposed by Bozorth. It is shown that the data fit well the assumption that the preferred orientation found in these chromium electro-deposits is the result of a slipping process, analogous to cold-working, which occurs during deposition when internal contractile stress reaches a certain critical value. It is further shown that the type of orientation found in chromium deposits is in accord with the theory and it is stated that (111) orientation is to be expected generally for body-centered cubic metals electro-deposited in a state of contractile stress, while (110) or (100) is to be anticipated for face-centered cubic metals deposited with the same type of stress. The orientations of a number of electro-deposited metals are shown to be in agreement with this expectation. Certain anomalies in the stress and orientation results for silver, nickel, and aluminum deposits have also been studied experimentally, and the results explained on the basis of the above theory. In conclusion, the possible mechanism of internal stress formation in electro-deposits is examined.
The Force Constants for CF4 and C2F6
Authors: Pace E. L.
Published: January 2005

Vibrational potential functions of the quadratic type for CF4 and C2F6, which assume no interaction between the CF3 groups in C2F6 and include only the interaction terms involving bond-bending with bond-stretching motions, are used with the observed normal frequencies to evaluate a set of force constants for the molecules. The force constants associated with the CF3 group are used interchangeably between the two molecules. The reproduction of the observed values of the normal frequencies resulting from the use of the force constants is of the order of five percent or better except for three of the frequencies. The omission of terms in the potential function for the interaction of the CF3 groups is largely responsible for the relatively poor reproduction of the type Eu frequencies of C2F6. Additional interaction terms, e.g., between bond-bending motions, are necessary for the improvement of the agreement in the case of the type F2 frequencies of CF4.
Steric Effects. II. General Equations. Application to Cis- and Trans−2-Butene
Authors: Hill Terrell L.
Published: January 2005

Steric energy and the semi-empirical method of calculating steric energy are discussed in the language of potential surfaces. Equations are given relating ΔH00 for several types of reactions commonly used to exhibit steric effects experimentally to the steric energy of the molecules involved in the reactions. The equations of Westheimer and Mayer for the calculation of the steric energy of a molecule are generalized in several respects. The difference in ΔH00 (formation) between cis and trans−2-butene is calculated as a steric effect. Because of various complications the application of the method in its present form to molecules such as H2O, NH3, PF3, etc., is rather unsatisfactory.
The Mercury Photosensitized Reaction of Dimethyl Ether
Authors: Marcus R. A. , Darwent B. deB. , Steacie E. W. R.
Published: January 2005

The mercury photosensitized reaction of dimethyl ether has been investigated at pressures between 28 and 500 mm and at temperatures between 25°C and 292°C. At 25°C the products consist almost entirely of hydrogen and 1,2-dimethoxyethane, and the initial step has been shown to be the abstraction of a hydrogen atom.

At higher temperatures CH2O, CH4, C2H6 and probably CH3OC2H5 become important products. They are derived from the decomposition of the methoxy methyl radical followed by subsequent radical recombination reactions. Carbon monoxide is produced in the later stages from the decomposition of formaldehyde.

By varying the light intensity and pressure it has been shown that ethane and dimethoxyethane are produced by second order recombination of methyl and methoxy methyl radicals respectively. The activation energies of the following reactions have been estimated: CH3+CH3OCH3→CH4+CH3OCH2E=9.0 kcal.  CH3OCH2→CH3+CH2OE=19 kcal.the only assumption being that methyl and methoxy methyl radicals recombine with zero activation energy.
Bond Energies of Hydrocarbons
Authors: Gerö L.
Published: January 2005

The spectroscopical dissociation scheme of CO gives for the heat of sublimation of carbon into 5S carbon atoms Lc=169,735 kcal./mole. This means an 84.58-kcal./mole average bond energy in diamond. The C–H bond energy of the methylene radical is 97.02 kcal./mole, the strength of the paraffinic C–C bond 82.59 kcal./mole, the olefinic double bond C=C is 145.12 kcal./mole. The rupture of successive bonds in methane requires 100.76, 97.36, 97.02, 97.02 kcal./mole.
Dissociation Schemes of Some Carbonyl Compounds
Authors: Gerö L. , Valatin J. G.
Published: January 2005

Dissociation schemes and bond energies are given for formaldehyde, acetaldehyde, acetone, and ketene. The distinction between dissociation term combinations which belong or do not belong to the lowest electronic state of the molecule is stressed, only energies corresponding to the former being in connection with bond energies. The survey of the different energetic possibilities may contribute to a better understanding of photo-chemical processes.
On Certain Integrals Useful in Molecular Orbital Calculations
Authors: Parr Robert G. , Crawford Bryce L.
Published: January 2005

Previous calculations of integrals which enter computations by the method of antisymmetric molecular orbitals are reviewed, several new integrals are evaluated, and a master table of integrals is given.
The Reaction of Atomic Hydrogen with Acetylene
Authors: Tollefson E. L. , Le Roy D. J.
Published: January 2005

The thermal dissociation of hydrogen on hot tungsten filaments has been used in the investigation of the reaction of atomic hydrogen with acetylene. A quantitative method has been developed for the detection of atomic hydrogen at pressures of the order of 10−3 mm. The catalytic effect of acetylene on the recombination of atomic hydrogen has been studied and the rate constant of the rate-determining step calculated to be 8.6×10−14 molecules−1 cm3 sec.−1 at 25°C. In contrast with results obtained by the discharge tube method, small amounts of hydrogenated products are formed.
The Effect of Electric Fields on the Decomposition of Nitrous Oxide by Alpha-Rays
Authors: Williams Nelson T. , Essex Harry
Published: January 2005

Combination of oppositely charged ions plays no part in initiating the decomposition of nitrous oxide by alpha-rays at 10 cm and at 20 cm pressure. The decomposition in the absence of a field is evidently largely initiated by the splitting of molecules on electron collision. The application of electric fields above those required to attain half-saturation increases the ion yield because of the acceleration of free electrons by the fields. At higher field strengths the ion yield attains a value which remains unchanged on further increase in field strength. When the ion yield has this final constant value all electrons are attached to form negative atomic or molecular ions before reaching the electrode. Assuming the same reactions occur on electron collision as in the photo-chemical reaction the increase in ion yield as a result of the effect of the field involves a minimum of 1.2 molecules of nitrous oxide split without attachment of the electron for each molecule split with attachment.
Molecular Orbital Treatment of the Ultraviolet Spectra of Benzene and Borazole
Authors: Roothaan C. C. J. , Mulliken R. S.
Published: January 2005

The ground state and the first excited states of benzene and borazole are treated according to the semi-empirical molecular orbital method. Comparing the observed spectra with the computed energies, a spectroscopic value of −2.6 ev for the bond integral β is obtained in the case of benzene. In the case of borazole this procedure includes one more parameter, which takes care of the difference in electronegativity of boron and nitrogen. Taking a reasonable value for this parameter, a value of −2.3 ev for the bond integral between boron and nitrogen, β*, is obtained in fair agreement with theoretical expectations.
The Effect of Certain Column Variables on Thermal Diffusion
Authors: Drickamer H. G. , O'Brien V. J. , Bresee J. C. , Ockert C. E.
Published: January 2005

Tests have been made on two thermal diffusion columns with different annular spacing. The results indicate that the dependence of the separation on temperature and annular spacing predicted by Furry, Jones, and Onsager holds. The dependence on pressure is slightly different than was predicted. The possibility that the index of repulsive force may depend on the pressure is pointed out.
Quantum Corrections to the Thermodynamic Properties of Liquids, with Application to Neon
Authors: Rice O. K.
Published: January 2005

The quantum correction has been expressed as a deviation η from lnQc, where Qc is the classical partition function. Changes in volume, energy, specific heat, etc., caused by quantization can be expressed in terms of η and certain thermodynamic quantities. η itself is expressed in terms of thermodynamic quantities. The equations obtained give for solid neon the same results, within the limits of error, as the usual treatment of a Debye solid with the aid of the Grüneisen equation. To apply the equation to liquid neon, various thermodynamic quantities have been obtained from known values for argon by use of the law of corresponding states. The difference in volume and specific heat of liquid neon from the values expected from the law of corresponding states have been computed and found to agree reasonably well with the observations. However, the melting point, and the ΔE and ΔS of fusion are found experimentally to be much closer to the classical values than one would expect from the theory. No explanation of this discrepancy is apparent.
Raman Lines of Second-Order Intensity in SnBr4, SnCl4, and CCl4
Authors: Welsh H. L. , Crawford M. F. , Scott G. D.
Published: January 2005

The characteristics of the faint Raman lines appearing in long exposures have been investigated for the molecules, SnBr4, SnCl4, and CCl4. All the lines observed have been classified as overtones and combination tones of the fundamentals. The depolarizations of the second-order lines were measured by means of a Wollaston prism placed between the collimator lens and the dispersing prism of the spectrograph. The depolarizations were found to be in accordance with theory, on the assumption of tetrahedral symmetry for the molecules. The intensities of the second-order lines relative to the fundamentals were measured. For the spherically symmetrical frequencies it is shown that the observed intensities can be explained by assuming that electrical and mechanical anharmonicities are both operative; in some cases counteracting one another and in other cases enhancing the effect of each other.
Studies of Surface Films by Reflection of Polarized Light. I. A More Rigorous Algebraic Method for Computing Results
Authors: Lucy F. A.
Published: January 2005

Plane-polarized light is in general elliptically polarized by reflection. Since the molecules in a very thin surface layer are those chiefly concerned in the process of reflection, the ellipticity is very sensitive to the interface conditions such as the presence of thin films. Since light changes phase 360° in a single wave-length, determination of phase changes to within a few minutes of arc should allow film thickness measurements to the nearest angstrom unit. The method has been used for many years to treat problems of wide variety. The instruments and techniques employed have, on the whole, been adequate, but the interpretation of results has often been more or less unsatisfactory. The algebraic relationship between instrument readings and film constants is not exactly known. Reasonably precise graphical solution is tedious. Algebraic solutions have been preferred by most workers.

This paper reports an algebraic method containing fewer approximations than used hitherto and compares results with values found by two prior methods. Drude's original equations give results in rather poor agreement with those of the more precise equations developed in this paper. Results obtained with the equations of Tronstad, on the other hand, agree fairly well in a favorable case.
An X-Ray Study of the Stepwise Melting of Anhydrous Sodium Palmitate
Authors: Nordsieck H. , Rosevear F. B. , Ferguson R. H.
Published: January 2005

X-ray powder patterns on anhydrous sodium palmitate show that the five phases already known to occur between crystal and isotropic melt can be grouped into two basic structures. Both structures are liquid crystalline, i.e., crystalline in the direction of the long spacing and liquid-like laterally. Between the lower temperature ``waxy'' structure, which includes the previously known subwaxy, waxy, and superwaxy phases, and the higher temperature ``neat'' structure, which includes subneat and neat, there is a pronounced break in the curve of long spacing vs. temperature; in addition, the three waxy phases exhibit two diffuse short spacing rings, whereas the neat phases exhibit only one. These pattern differences lead to the interpretation that the waxy phases contain structural restraints on molecular position and motion not present in the neat phases.
Force Constants for Some Halomethanes
Authors: Decius J. C.
Published: January 2005

Valence-type force constants, including several interaction terms, have been deduced from some of the experimentally observed fundamental vibration frequencies of the molecular sequence CX4, CX3Y, CX2Y2, CXY3, and CY4 in which X may be chlorine or bromine, Y hydrogen or deuterium. By assuming that the force constants are invariant for the different molecules and by neglecting several interaction constants associated with two bending motions, the number of distinct constants was reduced to 28, from which, after slight adjustment, 100 vibration frequencies were calculated. The quality of the fit with the experimental frequencies is indicated by a reasonably low root mean square deviation between calculation and observation (1.1 percent for 82 frequencies) and by the success of the constants in predicting 22 of the frequencies which were not used in the initial numerical evaluation of the constants.
The Effect of Variations in Surface on the Photolysis of Acetone
Authors: Steacie E. W. R. , Darwent B. deB.
Published: January 2005

An investigation of the acetone photolysis in the ``continuum'' and in the ``banded'' region has been made in clean quartz vessels and in vessels coated with potassium chloride and with lead. No appreciable change in the C2H6/CO ratio occurs in the coated vessels. This is surprising since biacetyl formation is apparently at least partly heterogeneous, and the ratio would be expected to be sensitive to the condition of the surface.

A few experiments were also made on the mercury photosensitized decomposition of acetone. Very high C2H6/CO ratios were found. It is concluded that this is due merely to higher absorbed intensities for a given incident intensity.
Ultrasonic Velocity in a Series of 1-Olefins
Authors: Lagemann R. T. , McMillan D. R. , Woolsey Martha
Published: January 2005

The ultrasonic velocity for the temperature range 10° to 30°C has been measured for seven members of a 1-olefin series. Densities and refractive indices were also measured. From the measurements, values of the molecular sound velocity, adiabatic compressibility, and molecular refractivity were computed. The ultrasonic velocity is found to vary linearly with temperature, while the molecular constant, MV⅓/d, remains substantially constant. The constant is found to be strictly additive for the series members studied.
Average Length and Radius of Normal Paraffln Hydrocarbon Molecules
Authors: Taylor William J.
Published: January 2005

The formulas previously published for the average (square) length and radius of long-chain molecules with restricted internal rotation are applied to a somewhat idealized model of the normal paraffin hydrocarbons. The potential barrier for rotation about the carbon-carbon single bond has been compounded of the usual threefold component plus a smaller onefold component which serves to stabilize the trans configuration of three successive bonds. Calculations are presented for a wide range of values of the parameters, and the most probable values of the parameters applicable to the normal paraffins, as determined from the thermodynamic and spectroscopic data, are discussed. The predicted ratios of the values of the average length and radius to the values calculated for free rotation are 1.76, 1.48, 1.36, and 1.29 at 0°, 100°, 200°, and 300°C, respectively. The effect of steric hindrance is discussed, and it is pointed out that the calculated values are probably appreciably low because of the neglect of steric hindrance.
Molecular Interaction and Infra-Red Absorption Spectra PART I. METHYL ALCOHOL
Authors: Davies Mansel
Published: January 2005

A study has been made of the absorption spectra between 3μ and 15μ of methyl alcohol at varying concentrations in solution. Clear indications are obtained of at least two new bands outside the 3μ region which arise from the associated molecules. The data allow of a further discussion of the vibrational assignments in methyl alcohol and it is hoped that some of the uncertainties in that respect have now been removed.
A ``Metallic'' Model for the Spectra of Conjugated Polyenes
Authors: Bayliss Noel S.
Published: January 2005

The π-electrons belonging to the double bonds of trans-conjugated polyenes are assumed to be a one-dimensional electron gas in a field of uniform potential energy whose length is approximately that of the conjugated system. The energy levels, the selection rule (Δn odd) and the transition intensities are deduced. The model predicts that the oscillator strength of the main absorption band of a trans-conjugated polyene is given by f = 0.134(2N+1), where N is the number of double bonds. The calculated values are in good agreement with experimental data. The wave number of the main band is related to the length of the conjugated system and the number of double bonds with moderately good agreement with experiment. The second, weaker absorption band of trans-carotene is discussed briefly.
Gas Heat Capacity and Internal Rotation in 1,2-Dichloroethane and 1,2-Dibromoethane
Authors: Gwinn William D. , Pitzer Kenneth S.
Published: January 2005

The gas heat capacity of 1,2-dichloroethane was measured in the temperature interval from 356°K to 556°K. The gas heat capacity of 1,2-dibromoethane was measured in the temperature interval from 383°K to 473°K. A potential barrier to internal rotation for 1,2-dichloroethane was selected which is in agreement with all of the data on heat capacity, entropy, and dipole moment of the gaseous molecule. An approximate barrier to internal rotation was selected for 1,2-dibromoethane.
The Transference Numbers of Sodium and Potassium Chlorides in 50-Mole Percent Methanol-Water Mixtures
Authors: Shemilt L. W. , Davies J. A. , Gordon A. R.
Published: January 2005

The transference numbers of NaCl and KCl in 50-mole percent methanol-water mixtures at 25°C have been measured for concentrations from 0.005 to 0.08 N, employing both autogenic cation and sheared anion boundaries. In the cation measurements, there was no progression in t+ as the boundary moved up the tube, and t+ was independent of current; the same was true of the anion measurements at 0.02 N over a considerable range of indicator ion concentration, and the sum t++t− was unity within experimental error. At 0.05 N, however, the measured t− varied with current and at moderate and high currents frequently showed progression with boundary movement. The Longsworth function t+∘′ is linear in concentration for the more dilute solutions, but the plot is definitely curved for the more concentrated. For both salts t+° is greater than in water, and the variation of t+ with concentration is distinctly different from that obtaining for aqueous solutions. A possible explanation is given for the latter effect.
Statistical Mechanics of Mixtures of Bose-Einstein and Fermi-Dirac Systems
Authors: Band William
Published: January 2005

Full quantum corrections are applied to Mayer's recent extension of statistical thermodynamics to the multi-component liquid phase. The resulting formulae are too general in nature to permit quantitative interpretation, but qualitatively, in the case of Bose-Einstein systems, the theory predicts a typical lambda-point condensation in momentum space. A Fermi-Dirac isotopic component dissolved to small concentrations in a Bose-Einstein liquid phase, like He3 in He4, is shown to behave to a first approximation independently of the Bose-Einstein degeneracy of the solvent at all temperatures above the lambda-point. The theory appears unable to handle the situation below the lambda-point.
The Reaction of Hydrogen Atoms with the Paraffin Hydrocarbons
Authors: Trost W. R. , Steacie E. W. R.
Published: January 2005

The reactions of atomic hydrogen produced by a discharge with ethane, propane, and neo-pentane have been investigated. All three reactions proceed at approximately the same rate, with activation energies of ca. 9 kcal., assuming a steric factor of 0.1. It is suggested, however, that the activation energies are in reality somewhat lower than this, with correspondingly smaller steric factors.

In the reaction with neo-pentane considerable ethane is produced. When deuterium atoms are used, this ethane is found to be only slightly exchanged. It is concluded, therefore, that ethane cannot arise by recombination of radicals, and must be formed in one step, presumably from an excited neo-pentane molecule.
Structure and Conductivity in the VIb Group of the Periodic System
Authors: von Hippel A.
Published: January 2005

In the sequence oxygen, sulfur, selenium, tellurium, and polonium a systematic alteration takes place from diatomic molecules, through ring and chain molecules, to a simple cubic lattice structure formed by atoms. This transition is paralleled by a modification in the electrical behavior from insulator (O,S), to semiconductor (Se,Te), to metal (Po). This paper is concerned with this progressive change in structure and conductivity and with the interrelation of the two phenomena. It discusses first the stability of ring and chain molecules and how the chain lattices of Se and Te may be derived by a simple distortion of the Po structure. Next, it considers schematically the electronic conductivity of selenium from the standpoint of the band picture, and finds that metallic Se is probably an intrinsic P-type conductor. Finally an alternative approach is suggested which connects structure and conductivity by extending qualitatively the concept of quantum-mechanical resonance from molecular structures to lattice structures and makes use of Pauling's resonating bond. The actual structure and conductivity of Se and Te thus appear as the outcome of a resonance between an insulating chain structure held by van der Waals cohesion and a metallic lattice of simple cubic structure, in which for Se the chain structure and for Te the Po lattice makes the stronger contribution.
On the Counting of Nodal Curves and Surfaces
Authors: Wintner Aurel
Published: January 2005

The classical oscillation theorem is extended so as to apply to potential fields corresponding to which the wave equation is not separable.
The Low Temperature Heat Capacities, Enthalpies, and Entropies of UF4 and UF6
Authors: Brickwedde Ferdinand G. , Hoge Harold J. , Scott Russell B.
Published: January 2005

The heat capacity of UF4 has been measured from 20° to 350°K and that of UF6 from 14° to 370°K. Molar heat capacities have been tabulated at 5-degree intervals and extrapolated to 0°K. From them the entropies and enthalpies of the compounds have been found by integration and tabulated. The triple point temperature of UF6 was found to be 337.212°K (64.052°C) and the heat of fusion was found to be 19,193 j mole−1.
Catalytic Isomerization of Butene−1 to Butene−2
Authors: Turkevich John , Smith Robert Kinsel
Published: January 2005

A study has been made of the interconversion of butene−1 and butene−2 on a variety of catalysts, both liquid and solid. This work was paralleled by the study of the exchange of radioactive hydrogen and tritium between the catalysts and the hydrocarbons, butene, propylene, and ethylene. A mechanism based on hydrogen transfer by the catalyst is proposed to explain the results and this mechanism is extended to apply to the action of catalysts in alkylation, cracking, and polymerization reactions.
Study of the Berthelot Method for Determining the Tensile Strength of a Liquid
Authors: Scott Arthur F. , Shoemaker David P. , Tanner K. Nolen , Wendel James G.
Published: January 2005

This paper describes an attempt to test directly the supposition that the high values for the tensile strengths of liquids as found by the Berthelot method are due to the trace of air ordinarily present in the Berthelot tube. A method is described for preparing Berthelot tubes in an evacuated system, using water from which air had been carefully removed. Measurements with these air-free tubes yielded 32 atmospheres as the average maximum hydrostatic tension that water can withstand. This value for the maximum tension is shown to be in good accord with evidence adduced recently by other investigators.
On the Order-Disorder Transition in Solids. Part I
Authors: Mutō Yosio
Published: January 2005

Although the phenomena of order-disorder transition and the phenomena of condensation have a marked difference, there is a great similarity in their statistical mechanical treatment. Considering a hypothetical gas in which the molecules can occupy only lattice points of a crystal, and treating the ``wrong'' molecules as the gas molecules and the ``right'' molecules as the empty points, the partition function of a binary mixture is easily computed by applying Mayer's method. It is then pointed out that the ordered state is the analog of a condensing system.
On the Order-Disorder Transition in Solids. Part II
Authors: Mutō Yosio
Published: January 2005

In a recent paper with the same title the author studied the phenomena of order-disorder transition in crystals with equivalent sublattices when there are just the same numbers of A and B molecules. In the present paper the case with variable numbers of molecules is considered. As a paper issued some years ago in Japanese contained some mistakes, a complete revision is made and the analogy with the condensation phenomena in two component systems is considered.
Thermodynamic Properties of the Internal Rotator. Double Minimum with Attractive Forces
Authors: Halford J. O.
Published: January 2005

A previously outlined general method of calculating thermodynamic properties for an unsymmetrical internal rotation is applied to a double minimum with attractive forces, for which the potential energy has two maxima at the same height and two minima at different heights. The entropy is lower than that of the system of two equal potential valleys or that for a single valley, and can be lower than the former by as much as R ln2 when the potential barriers are high. This decrease tends to disappear in the region of close approach to free rotation, when the barriers are lower than RT. For very high potential barriers, if one of two equal minima is raised, the system acquires the properties of a simple harmonic oscillator.
Intrinsic Viscosity, Diffusion, and Sedimentation Rate of Polymers in Solution
Authors: Debye P. , Bueche A. M.
Published: January 2005

Intrinsic viscosity, diffusion and sedimentation rate of polymers in solution is calculated by a generalization of Einstein's theory for impermeable spheres. For the coiled polymer molecule a sphere is substituted which hinders the liquid flow through its interior only to a degree depending on the average density in space of the polymer molecule in solution. The amount of shielding of the liquid flow which is introduced in this way determines the exponent in the customary exponential relation between intrinsic viscosity, diffusion, or sedimentation rate and molecular weight. This relation is shown to have only the merits of an interpolation formula. It is shown how the dimensions of the molecular coil can be derived from the experimental data on viscosity, and these dimensions are compared with those derived from interference measurements. The point is stressed that the relation between intrinsic viscosity and molecular weight is rather indirect and depends essentially on the type of polymer molecule under consideration. In most cases polymer molecules are decidedly stiffer and therefore cover a larger space in solution than would be expected from models with free rotation around bonds.
The Heat of Dissociation of Nitric Oxide
Authors: Glockler G.
Published: January 2005

The heat of dissociation of nitric oxide (D(NO)) is considered to be 6.49 ev on the basis of a comparison of the series CO, NO, O2, OF, its band spectrum, and its photo-chemical dissociation. Appearance potentials of N+, O+, and O− can be interpreted on this basis.
The Molecular Diagram Method
Authors: Daudel Pascaline , Daudel Raymond
Published: January 2005

The ``importance'' of various valence bond formulas, including monoexcited and diexcited formulas, is calculated for a number of resonating organic molecules By ``importance'' is meant the square of the coefficient of its wave function Several applications of the derived values are discussed
Structure of Micelles of Colloidal Electrolytes. III. A New Long-Spacing X-Ray Diffraction Band, and the Relations of Other Bands
Authors: Mattoon R. W. , Stearns R. S. , Harkins W. D.
Published: January 2005

A newly found x-ray diffraction band, obtained from aqueous solutions of soaps and detergents, gives a Bragg spacing which is independent of concentration and is close to the double-length of the molecule. This is designated as the micelle thickness or M-band. The already known long-spacing band, interpreted here as related to the inter-micellar distance, is designated as the I-band. Its spacing dI increases with decreasing soap concentration. If a hydrocarbon is solubilized in the micelles, these spacings increase by ΔdM and ΔdI. Formerly, ΔdI was supposed to give the mean thickness of the layer of oil dissolved between the ends of the hydrocarbon chains of the soap molecules as a middle layer in the micelle. However, ΔdM seems to be more directly related to this thickness. As measured by dM, the thickness of the micelle remains constant with increasing soap concentration: e.g., the values are 40.8, 41.5, 40.7, 40.2, 39.5, 39.6, 40.2A for potassium myristate at 25°C at the following respective concentrations: 2.3, 4.5, 7.2, 9.8, 12.0, 13.7, and 16.5 percent. The mean ``thickness'' increases from 29.7A for potassium caprylate (C8) to 47.3 for potassium palmitate (C16). By a method explained in the text, the number of molecules in a potassium myristate micelle is calculated as 56 at 9.8 percent by use of the Bragg I-spacing. However, it is probable that a corrected Bragg spacing should be used. A new long-spacing band, designated as an X-band, appears when an I-band is present and oil is solubilized in the micelles. The order of spacing is then dI>dM>dX; e.g., in one case the values are 84>50>27A.

The ``cylindrical'' model of the micelle preferred here differs from the lamellar and in some respects from the spherical model. It exhibits the following characteristics: (1) A micelle consists of one double-layer of soap or detergent molecules. These have their polar ends oriented outward toward the water and their non-polar ends inward toward each other. (2) The thickness of the micelle of a pure soap is essentially twice the length of the soap molecule, independent of concentration. (3) Hydrocarbons solubilize inside the micelle between the two layers of soap molecules and thus make he micelle thicker. (4) The area per soap molecule in the micelle remains practically constant, whether or not solubilized hydrocarbons are present. (5) The width or lateral dimension of the micelle and the number of soap molecules per micelle increase with increasing soap concentration and with solubilization of hydrocarbons. (6) From energy considerations the area of contact between the hydrocarbon chains of the detergent molecules and the water must be as small as is compatible with the other conditions imposed upon its structure.
The Heat and Free Energy of Polymerization of Ethylene
Authors: Jessup R. S.
Published: January 2005

Values calculated from available thermochemical and chemical thermodynamic data are given for the heats and free energies of polymerization of gaseous ethylene to gaseous, straight-chain polyethylene (monoolefin) molecules of various lengths. Equations are given expressing these properties at 25°C as functions of n, the number of ethylene units per polymer molecule, for n≧3. The limiting values at 25°C for long-chain molecules are ΔHp°=−22.348 kcal. per ethylene unit, ΔFp°=−12.186 kcal. per ethylene unit. A preliminary value for the heat of combustion of solid polyethylene at 25°C, ΔHc°=−311.8 kcal. per ethylene unit, is combined with other data to obtain the value ΔHp°=−25.4 kcal. per ethylene unit for the heat of polymerization of gaseous ethylene to solid polyethylene. This experimental value and the calculated value for gaseous polyethylene are shown to be consistent within reasonable limits when account is taken of the heat of sublimation of the partly crystalline polyethylene, estimated to be 3.6 kcal. per ethylene unit. Values are given graphically and in tabular form for the equilibrium concentrations of ethylene and all its polymers at various temperatures in a mixture in the ideal gas state at a pressure of 1 atmosphere.
Note on a Relation between the Order of a Phase Transition and Discontinuities in the Distribution Functions of Molecules
Authors: Mayer Joseph E.
Published: January 2005

It is pointed out that in a phase transition of the n'th order the distribution functions for n molecules change discontinuously at the transition point.
The Mechanism of Flame Propagation
Authors: Hoare M. F. , Linnett J. W.
Published: January 2005

Recently Tanford and Pease have shown that in a number of carbon monoxide flames the burning velocity increases as the calculated equilibrium concentration of hydrogen atoms in the flame front increases. They point out that this would be so if the propagation of the flame were dependent on the diffusion of hydrogen atoms ahead of the flame. It is shown in the present paper that, by combining calculated ignition and flame temperatures, the variation in burning velocity with composition can also be accounted for on an essentially thermal theory of flame propagation.
Consideration of the Gibbs Theory of Surface Tension
Authors: Tolman Richard C.
Published: January 2005

The Gibbs theory of surface tension is discussed. Detailed consideration is given to the structure of transition layers between phases. This provides theoretical information, as to the magnitude of surface tension and as to the location of the surface of tension, which can be used in making applications of the Gibbs theory.
The Vibrational Spectrum and Thermodynamic Functions of Acrylonitrile
Authors: Halverson Frederick , Stamm Robert F. , Whalen John J.
Published: January 2005

The infra-red spectra of gaseous and liquid acrylonitrile have been studied from 2.5 μ to 25 μ with a spectrometer using LiF, CaF2, NaCl, and KBr prisms. The Raman spectrum of the liquid has been obtained, including intensity and polarization data. A normal coordinate calculation of the non-planar frequencies has been made, using force constants from related molecules. This information permits a complete assignment of the fifteen fundamental frequencies and a calculation of the thermodynamic quantities for the molecule.
Note on an Equation of State for Linear Macromolecules in Monolayers
Authors: Singer S. J.
Published: January 2005

An equation of state for monolayers of large threadlike molecules based on the highly idealized quasi-lattice model is presented, and applied with fair success to the small number of experimental data available. Although protein molecules in monolayers may be highly organized structures, the theory can be applied to them at moderate film pressures without requiring unreasonable values for their molecular parameters. By analogy with the three-dimensional case, the theory requires improvement in order to apply to the low pressure regions, where experimental differences between protein and polymer films should become more marked.
The Magnetic Susceptibilities of Some Uranium (IV) Compounds
Authors: Hutchison Clyde A. , Elliott Norman
Published: January 2005

The magnetic susceptibilities of U(SO4)2·3.26H2O, U(C2O4)2·5H2O and U(C5H7O2)4 have been determined at a series of temperatures from the boiling point of liquid N2 to 60°C. The Weiss-Curie law is obeyed at temperatures above 195°K. The data indicate the presence of two 5f electrons in the ground state. The susceptibility of Th(C5H7O2)4 at room temperature has also been determined.
A Further Investigation of the Mercury Photosensitized Polymerization of Propylene
Authors: Gunning H. E. , Steacie E. W. R.
Published: January 2005

A reinvestigation has been made of the authors' earlier work on the reaction of propylene with mercury (3P1) atoms at 30°C in a static system, with special concentration on the products of the reaction.

The mechanism C3H6+Hg(3P1)→C3H6*+Hg(1S0)C3H6*+C3H6→2C3H6C3H6*→C3H5+Hwhich was proposed in the earlier work has been confirmed. Some twenty-two different products were identified at low pressures, all of which, with the exception of acetylene, can be explained as the result of interactions of the free radicals present.

The quantum yield of the reaction reaches a maximum of 0.18 at 6.5 mm, and falls to 0.04 at 72 mm.
The Raman Spectra of Boron Trifluoride, Trichloride, and Tribromide. The Effect of the Boron Isotopes
Authors: Anderson Thomas F. , Lassettre Edwin N. , Yost Don M.
Published: January 2005

The Raman frequencies v1{1}, 2v2{2}, v3{2}, and v4{2} for BF3(g), BCl3(l), and BBr3(l) were found to be 886 and 783, 1394, 1038 and 1105, 440; 471, 924, 958 and 996, 243; 279, 743, 806 and 846, and 151 cm—1, respectively. The assignment of frequencies was determined by polarization experiments on BCl3 and is confirmed for the three compounds by the results of a normal coordinate treatment. The doubling of v1 in BF3 is ascribed to vibrational resonance between v1 and 2v4. The doubling of v3 in all three compounds is shown to be due to the presence of the two isotopes of boron B10 and B11. A satisfactory assignment of the infrared frequencies of BCl3 is made.
The Infrared Absorption Spectra of Dioxane-Water Mixtures
Authors: Gordy Walter
Published: January 2005

The absorption spectra of various dioxane-water mixtures have been studied in the region 2.5μ to 6.5μ. Dioxane was found to produce marked changes in the water spectrum. The observed variations are more pronounced for low water concentrations. Association of the water and dioxane molecules is suggested as a possible explanation of the observed effects.
The Thermal Decomposition of Divinyl Ether
Authors: Taylor H. Austin
Published: January 2005

The thermal decomposition of divinyl ether has been studied at temperatures between 460° and 500°C, and at pressures from 30 to 1000 mm. That the reaction has a chain mechanism, chains being broken on the walls at low pressure and in the gas phase at high pressure, is concluded from the effects of (a) increased surface, (b) added nitrogen (c) varying temperature coefficient with pressure and (d) induced decomposition with azomethane. The over-all order at high pressure is three-halves judged both from the individual velocity constants during a run and from the variation of velocity constant with pressure.
I. Calculation of Energy of H3 Molecule
Authors: Hirschfelder J. , Eyring H. , Rosen N.
Published: January 2005

The potential energies for linear symmetrical configurations of the triatomic hydrogen molecule have been calculated by the variational method with hydrogen-like 1s atomic orbitals by varying the ``effective charge'' and the amount of all polar and homopolar states in the eigen-function. The lowest energies (in kcal./mole = 1/23.06 ev) and corresponding separations between neighboring atoms (in Bohr radii) are given in the table. The activation energies are for the reaction H+H2→H2+H, and are calculated with the same type of approximation for H2 and H3. All of the difficult three-center integrals for the repulsions between pairs of electrons were calculated explicitly in ellipsoidal coordinates without the use of infinite series. Heithler−LondonH.L. plus PolarWangWang plus PolarExperimentEH3−3EH−53.11−60.39−56.16−67.09−103.rH32.002.001.891.84Act. Energy19.0713.6330.6825.157.
Molecular Constants and Potential Energy Curves for Diatomic Molecules. II
Authors: Huggins Maurice L.
Published: January 2005

The potential energy expression U=e−a(r−r12)−C′ e−a'(r−re) previously applied to diatomic molecules containing only first row elements is now applied to other types. For most of them the same value of a (6.0 × 108 cm—1) can be used satisfactorily, the r12 values then being additive and depending only on the row of the periodic table in which the atoms occur. Molecules containing but few electrons require different values of a and r12. Values of the equilibrium distance re, calculated from ωe, ωeχe and these constants, are in most cases within 0.02 or 0.03A of the experimentally determined distances (see Table V). The relation between Badger's empirical equation for the calculation of re and the equations used in this paper is discussed.