bluuebunny/crossref_metadata_2025 huggingface dataset:
An X-Ray Investigation of the Structure of Lead Chromate
Authors: Brody Selma Blazer
Published: January 2005

An attempt to analyze the structure of lead chromate was undertaken, using the Weissenberg x-ray goniometer technique. Positions of the lead and chromium atoms were determined. Although the intensities were carefully corrected for absorption, accurate values of the oxygen parameters could not be determined from the data at hand. Further work is indicated. There is some discussion of the migration of ions in the photoblackening effect which lead chromate exhibits.
Infra-Red and Raman Spectra of Polyatomic Molecules XVII. Methyl-d3-Alcohol-d and Methyl-d3-Alcohol
Authors: Noether Hermann D.
Published: January 2005

CD3OD and CD3OH have been prepared and their infra-red spectrum in the range from 2.5μ to 18μ has been measured. The Raman spectrum of CD3OD has been observed. CH3OH and CH3OD have been reinvestigated and an assignment for all four methyl alcohols has been given.
Spectroscopic Studies of the Simpler Porphyrins IV. The Absorption and Fluorescence Spectra of ms-Tetra(3′,4′-methylenedioxyphenyl)porphine of HCl Number Four and of Its AgC5H5N, Zn, and Ni Complex Salts
Authors: Albers V. M. , Knorr H. V. , Fry David L.
Published: January 2005

The molecular absorption coefficients of ms-tetra(3′,4′-methylenedioxyphenyl)porphine and the AgC5H5N, Zn, and Ni complex salts have been measured over the visible region of the spectrum. The curves representing the absorption coefficients as a function of the wave-length are shown. The spectra of this porphyrin and its metal complex salts are quite similar to those of ms-tetraphenylporphine and its corresponding metal complex salts. The fluorescence spectra of these substances have also been studied. All four substances fluoresce in the red region of the visible spectrum. Curves showing relative intensity of fluorescence as a function of wave-length are shown for the parent substance and the Zn complex salt. The fluorescence of the AgC5H5N and Ni complex salts is so weak that intensity measurements could not be made.
The Differences in the Vapor Pressures and Entropies of the Liquid Nitrogens
Authors: Kirshenbaum Isidor
Published: January 2005

The differences in the thermodynamic properties of liquid nitrogen (14) and liquid nitrogen (15) are discussed on the basis of several Debye-like models. The quantum mechanical effects are found to be greater than one could expect from an harmonic oscillator model. Other factors affecting these properties are considered.
Mechanism of the Photolysis of Propionaldehyde
Authors: Garrison Warren M. , Burton Milton
Published: January 2005

The photolysis of propionaldehyde at λλ2537, ∼2900, and ∼3200A has been studied by the Paneth mirror method. The alkyl radicals produced are exclusively ethyl; no atomic hydrogen can be detected by the guard mirror method in amounts exceeding 2 percent of the total number of mirror-active particles present. The yield of C2H5 radicals has been determined and compared with the yields of CO, H2, and C2H6. The results are most readily interpreted in terms of competing primary decomposition processes producing free radicals in one reaction and ultimate molecules in another. Whereas the former reaction increases in importance at shorter wave-lengths, the latter becomes less significant. On the other hand, an explanation for the results can be given on the basis of a mechanism involving only the production of free radicals in the primary process at all wave-lengths. The role played by excited propionaldehyde molecules (of life which may be >10−3 sec.) and by freshly formed (energy-rich) C2H5 and HCO radicals on their first collision is also considered. The mechanism of energy transfer within the propionaldehyde molecule is discussed and it is shown that the products of the primary decomposition are probably determined by geometric considerations and by the relative heights of the dissociation levels involved in the normal state.
The Thermal Decomposition of n-Butylamine
Authors: Beachell Harold C. , Taylor H. Austin
Published: January 2005

The thermal decomposition of n-butylamine proceeds in a manner analogous to that of the lower aliphatic amines. There is no evidence to support the suggestion of a molecular split into ammonia and ethylene. The mechanism appears to involve initially the production of a butylamino radical and a hydrogen atom. The butylamino radical may be the source of the ammonia found, by production of an imine whose presence is indicated. Pressure change rates yield an apparent energy of activation of 89 kcals.
The Variation of the Transference Numbers of Sodium Chloride in Aqueous Solution with Temperature. II
Authors: Allgood R. W. , Gordon A. R.
Published: January 2005

The transference numbers of sodium chloride in aqueous solution at temperatures from 15° to 45° for concentrations up to 0.1N have been determined by the moving boundary method; both anion and cation boundaries were employed. The results for 25° are in close agreement with those of Longsworth. The Longsworth function t+°′ is linear in the concentration for the more dilute range at all temperatures, thus permitting a satisfactory extrapolation to infinite dilution, but shows definite deviations from linearity for the more concentrated. The transference numbers for sodium chloride and those previously obtained for potassium chloride, combined with the conductance data reported in the accompanying paper, yield values of the ionic mobilities for the whole temperature range.
The Conductance and Ionic Mobilities for Aqueous Solutions of Potassium and Sodium Chloride at Temperatures from 15° to 45°C
Authors: Gunning H. E. , Gordon A. R.
Published: January 2005

The conductance of aqueous solutions of potassium and sodium chloride has been determined at 15, 25, 35 and 45°C for concentrations from 0.0005N to 0.01N by a modified direct-current method of high precision. At 15° and 25°, the results are in highly satisfactory agreement with the best of the existing data obtained by the a.c. bridge method. For all temperatures, the conductance can be represented within a few hundredths of a percent by the extended Onsager-Shedlovsky equation. A calculation of the mobility of chloride ion from the conductance and the transference numbers obtained in this laboratory shows that for all temperatures the Kohlrausch rule of independent ionic mobilities is obeyed at infinite dilution within the apparent limit of error of the measurements—0.02 to 0.03 percent. The conductance and ionic mobilities for round values of the concentration, and the temperature coefficients of the ionic mobilities at infinite dilution are tabulated.
Statistical Thermodynamics of Rubber
Authors: Wall Frederick T.
Published: January 2005

The entropy change for the stretching of rubber is calculated by statistical methods, neglecting intermolecular attractions and deformation of bonds and bond angles. The calculation involves the probability of finding the system with a given distribution of molecular configurations. An equation of state relating the tension, length, and temperature of a rubber band is then derived. Following this a discussion of the applicability and the limitations of the theory is presented.
X-Ray Interference in Partially Ordered Layer Lattices
Authors: Hendricks Sterling , Teller Edward
Published: January 2005

The x-ray interference is calculated for layer lattices in which the phase shifts between consecutive layers and the scattering powers of individual layers do not follow a strictly periodic arrangement. In the second section the scattering power of all layers is assumed to be the same but the phase shifts can take on different values. In the third section neither the scattering powers nor the phase shifts have fixed values but a simplifying assumption is made about the phase shifts according to which distances between neighboring layers can be represented as sums of two distances characteristic of the individual layers. In both these sections a random sequence of the layers is assumed. In the fourth section the problem of arbitrary scattering powers and phase shifts is treated, and furthermore a statistical correlation between neighboring layers is introduced. In the following section the general theory is applied to a specific partially ordered stacking of layers encountered in micas and other similar minerals. The last section treats irregularities in close packed structures of spheres and irregular sequences of layers in graphite.
Raman Spectra of Acetylenes VI. 1-Butyne, 1-Pentyne, 1-Hexyne, 3-Hexyne, 4-Octyne and 1-Chloro-1-heptyne
Authors: Cleveland Forrest F. , Murray M. J. , Taufen H. J.
Published: January 2005

Raman displacements, estimated intensities and depolarization factors have been obtained for CH3CH2C≡CH, CH3(CH2)2C≡CH, CH3(CH2)3C≡CH, CH3CH2C≡CCH2CH3, CH3(CH2)2C≡C(CH2)2CH3, and CH3(CH2)4C≡CCl. The data obtained in the 2200 cm−1 region were [2068(1)P], 2118(10)0.5, 2158(3)0.5; [2064(0)], 2118(10)0.5; 2071(0), 2094(0), 2118(10)0.4; 2200(1)P, 2231(9)0.4, 2247(8)0.4, 2301(6)0.4; 2234(10)0.5, 2292(6)0.5; 2148(1)P, 2194(1)P, and 2243(10)0.4, respectively. Unusual features are the appearance of the second strong line at 2158 cm−1 in the spectrum of 1-butyne and the absence of the line near 2245 cm−1 in the spectrum of 4-octyne. Introduction of the Cl atom in the last compound radically modifies the spectrum in this region.
Zinc Photosensitized Reactions of Ethylene
Authors: Habeeb H. , LeRoy D. J. , Steacie E. W. R.
Published: January 2005

An investigation has been made of the polymerization of ethylene photosensitized by zinc, both resonance lines, 2139A and 3076A, being used. With λ3076 the rate of the reaction is very small, and it is concluded that this is probably due to inefficient quenching. With λ2139 a rapid polymerization occurs. The products of the reaction are propylene, butene, and small amounts of higher hydrocarbons. Acetylene formation is negligible. The rate of polymerization increases rapidly with increasing ethylene pressure. While there is some doubt about the mechanism, the most plausible suggestion seems to be that the initial step is Zn(41P1)+C2H4=ZnH+C2H3,and that this is followed by an atom and free radical sensitized polymerization of ethylene.
Exchange of Radioactive Silver with Silver Chloride Suspensions
Authors: Langer A.
Published: January 2005

From exchange experiments on radioactive silver in solution with silver chloride in suspension, it can be shown that the silver ions in solution are constantly exchanging with the silver ions in the precipitate. This exchange is not limited to the surface of the crystals, but, probably by means of self-diffusion, is propagated into the precipitate. A steady radioactive state obtains when a homogeneous distribution of the radioactive silver throughout the whole system is reached. The time necessary to obtain a given fraction of complete exchange for a given amount of precipitate depends strongly on the area of the crystal surface.
Electronic Structure and Stability of Hydrogen Halides and of Complex Ions XO4
Authors: Fajans Kasimir , Bauer Norman
Published: January 2005

(1) It is shown that in the hydrogen halide molecules (internuclear distance r0) the proton penetrates the electronic shell of the anion to a depth which for the simplified case of spherical symmetry can be characterized by the condition: The amount of negative charge beyond the sphere of radius r0 equals −1e. (2) From the dipole moments μ=xer0 of the hydrogen halide molecules it can be concluded: The wave mechanical distribution of the negative charge of the free halide ions is changed by the introduction of the proton in such a way that the center of gravity of an amount of charge equal to —(1−x)e is shifted from the halogen nucleus to the proton. The fraction (1—x) increases with the electronic polarizability of the anion, and would be equal to 1 for an ion of infinitely large polarizability, leading to a completely unpolar type of binding in this case. (3) It is shown that for the complex ions SiO44—, PO43—, SO4=, and ClO4−, the gradation of the X–O distances and of the molar dispersion can be easily understood from the point of view used in 1924 for the case of the molar refraction: These ions represent the result of the polarization of O= by Si4+, P5+, S6+, and Cl7+, and the X–O binding in them shows gradual changes toward the unpolar type. (4) It is pointed out that the relatively unstable HI and ClO4− approach the unpolar type of binding more closely than any other of the compounds considered here. The generalization of this connection between instability and the degree of deformation of electronic shells explains why compounds like FO4− and BrO4− are unknown.
Efficiency of the Electrolytic Separation of Chlorine Isotopes
Authors: Johnston Herrick L. , Hutchison Dwight A.
Published: January 2005

The electrolytic separation coefficient α has been determined for the chlorine isotope separation in the electrolysis of sodium chloride solutions at a platinum anode. Flotation of purified NaCl crystals in ethylene dibromide was employed as the analytical procedure in determining the isotopic composition of samples. Densities of the ethylene dibromide as a function of temperature were separately determined. The electrolytic separation factor for Cl isotopes was found to be 1.0060±0.0005 for the temperature range 25° to 40°C. No significant dependence on either temperature or current density was observed. The coefficient on platinum (1.0060±0.0005) agrees with the value on Acheson graphite (1.0068±0.0014) which may be computed from the data of Yacouban.
Determination of the Lennard-Jones Parameters from Second Virial Coefficients Tabulation of the Second Virial Coefficient
Authors: Stockmayer Walter H. , Beattie James A.
Published: January 2005

Values of B/(2πNσ3/3) to four decimal places as a function of θ/T are computed from θ/T=0.20 to 1.00 for a Lennard-Jones (6, 12) potential. The equation B/(2πNσ3/3) = (θ/T)¼[1.064–3.602(θ/T)] computes the tabulated values fairly well. Thus σ and θ can be determined from experimental B values by plotting BT¼ against 1/T and finding the slope and intercept of the best straight line through the points. For methane and n-butane this method gave parameters that computed B values agreeing with observed values within the experimental uncertainty.
The Diffraction of X-Rays by Liquid Oxygen
Authors: Sharrah P. C. , Gingrich N. S.
Published: January 2005

The x-ray diffraction pattern of liquid oxygen at 89°K shows an intense peak at sin θ/λ = 0.157, and very weak peaks at 0.35 and at 0.5; that at 62°K shows an intense peak at 0.159, and weak peaks at 0.35 and at 0.5. The atomic distribution curves have peaks at 1.3A, 2.2A, 3.4A, and 4.2A for 89°K, and at 1.25A, 2.15A, 3.2A, and 4.1A for 62°K. The first peaks are due to the interatomic distance in the diatomic molecule, the second may be due to triatomic oxygen, and the others may be due to higher molecular aggregates.
On the Absorption Spectrum of Some Polymethine Dyes
Authors: Herzfeld Karl F.
Published: January 2005

The energy levels of certain polymethine dyes are calculated approximately. The dyes consist of a chain of conjugated double bonds, with end groups which might or might not differ from each other. Ions and neutral molecules are treated. The calculations are performed both with the valence bond method (resonance between different structures) and the LCAO method, but without antisymmetrization and without taking electronic interaction into account. The effect of chain length and of the nature of the end groups is discussed.
Energy Levels and Color of Polymethine Dyes
Authors: Sklar A. L.
Published: January 2005

The secular determinant for the energy levels of the unsaturation electrons of a polymethine dye is discussed in both HLSP and LCAO approximations. The roots of the secular determinant, which were obtained in the preceding paper by Herzfeld, are applied to a discussion of the longest wave-length electronic band of symmetrical and unsymmetrical polymethines. The LCAO approximation gives good numerical values for the dependence of both the transition energy and oscillator strength on the length of the polymethine chain in symmetrical dyes, but cannot handle the questions which depend sensitively on a small difference between the groups attached to the two nitrogen atoms at the extreme ends of the chain. Although the HLSP method yields correct qualitative results for symmetrical dyes, it does not give good numerical values. The HLSP method, however, is sensitive to a difference between the two ends of the dye molecule and affords a simple explanation for a number of properties in which unsymmetrical dyes differ from symmetrical ones.
Statistical Distribution Laws for Rate Processes 2. Non-Uniform Distributions
Authors: Longtin Bruce
Published: January 2005

The methods developed in the previous paper are used to determine the most general form of statistical distribution law suitable for the treatment of rate processes. The result is particularly applicable to relatively dense systems composed of soft molecules. It is based on the assumptions that each variable whose rate of change is to be measured must be statistically reproducible at all times, and that the molecular motions are not seriously discontinuous. Various special forms of the distribution law result from different ways of expressing the rate variables and experimental conditions. One form is derived for the case in which the rates of change of the average position and kinetic energies of the molecules are to be reproducible. Qualitatively, it agrees with the known frequent behavior of rate experiments, showing frictional dissipation of energy, and the tendency to return to equilibrium. Furthermore, it reduces to the classical distribution law under equilibrium conditions.
Vibration-Rotation Energies of Planar ZXY2 Molecules Part II. The Quantum-Mechanical Hamiltonian and the Energy Values
Authors: Silver Samuel
Published: January 2005

Nielsen's treatment of the vibration-rotation energies of a general polyatomic molecule is applied to the planar ZXY2 molecular model. Due to the low symmetry of the model, the vibrational modes are non-degenerate, and, if the frequencies are well separated in their values, Nielsen's general formulation can be applied directly. For this case the elements of the secular equation are evaluated to include all the first- and second-order terms in the Hamiltonian. With the view of applying the theory to the analysis of the fundamental bands of formaldehyde, the effect of an approximate degeneracy between a pair of perpendicular vibrations, of symmetry types B1 and B2, respectively, is considered. For this case, the vibration-rotation energies of the states giving rise to the fundamental bands are investigated to the first order of approximation. It is shown how, by a modification of Nielsen's general treatment, the secular equations can be set up with little difficulty to include all the first-order terms in the Hamiltonian. The secular equations for values of J = 0, 1, 2, 3, 4 are given explicitly.
Thermal and Photochemical Decomposition of Gaseous Aluminum Trimethyl
Authors: Yeddanapalli Lourdu M. , Schubert Clarence C.
Published: January 2005

The thermal decomposition of gaseous aluminum trimethyl, in the absence of hydrogen, is nearly 94 percent homogeneous and of kinetic order three-halves over the pressure range 10 to 85 mm measured at room temperature. The reaction products consist largely of methane and to a lesser extent ethane, ethylene, and hydrogen and a solid deposit on the walls of the reaction vessel. A reaction mechanism involving methyl radicals is proposed. The apparent energy of activation, calculated on this basis, is found to be 45 kcal., in agreement with the experimentally determined figure. The high ratio of methane produced to alkyl decomposed suggests that aluminum trimethyl in the vapor state at room temperatures must consist at least of tetrameric molecular complexes. In the presence of hydrogen, both the decomposition rate and the energy of activation are reduced as compared to the decomposition of the pure alkyl, a puzzling effect for which no satisfactory explanation can at present be offered. Photochemically, the presence of hydrogen seems to have little effect on the over-all decomposition but enhances the relative amount of methane slightly. In this, aluminum trimethyl appears to differ from mercury dimethyl which is known to decompose faster thermally and photochemically in the presence of hydrogen than in its absence.
Network Analyzer Tests of Equivalent Circuits of Vibrating Polyatomic Molecules
Authors: Carter G. K. , Kron G.
Published: January 2005

To illustrate the use of the equivalent circuits derived in the companion paper for vibrating polyatomic molecules, this paper describes network-analyzer tests of circuits for three successively more complicated molecules. The first is the symmetrical linear CO2 molecule; the second is the unsymmetrical linear OCS molecule; and the third is the unsymmetrical nonlinear CH3CH2OH molecule. In each case, starting from given constants of the molecular structure, the normal frequencies and modes are measured by means of the equivalent circuit. It is shown that for these cases the analyzer measurements agree satisfactorily with the known normal-frequency characteristics.
The Asymmetric Rotor III. Punched-Card Methods of Constructing Band Spectra
Authors: King Gilbert W. , Cross Paul C. , Thomas George B.
Published: January 2005

The stochastic method of analysis of band spectra of asymmetric rotors involves the calculation of line strengths and positions for successive estimates of six molecular constants, until the calculated intensities at all wave-lengths agree satisfactorily with the observed. This paper shows that these extensive calculations, as based on tables previously published, are well adapted to standard punched-card equipment. In addition to the above calculations, it is possible to construct the appearance of the rotational structure for various values of slit width. The procedure is carried through for H2S with some approximate constants. Very satisfactory representations of observed spectra are obtained for completely resolved spectra, as in the photographic region; for slit width 1 and 2 cm−1, as in the near infra-red; for slit width 10 cm−1, as in poorly resolved infra-red spectra.
Some Thermodynamic Constants for the Solution Processes of Atoms in Metallic Solvents
Authors: Wang Sheng-Nien
Published: January 2005

By combining the gas-metal equilibrium data available in literature and the thermodynamic quantities of gaseous molecules and atoms from the method of statistical mechanics, thermodynamic constants for the solution processes of some atoms in some metallic solvents have been obtained.
The Theory of the Racemization of Optically Active Derivatives of Diphenyl
Authors: Westheimer F. H. , Mayer Joseph E.
Published: January 2005

T. L. Hill has recently shown that it is possible to compute the magnitude of steric strain in certain organic molecules. The present paper summarizes the results of a similar but independent investigation directed towards a computation of the rate of racemization of optically active (i.e., sterically hindered) derivatives of diphenyl. The energy of the planar form of a sterically hindered diphenyl can be approximated by the equation: E= ∑ i12aiqi2+Aiexp (−d1/ρ1)+A2exp (−d2/ρ2),where the qi are the normal coordinates of the unstrained molecule in question and the exponential terms are approximations (over the limited range of interest) to the steric repulsions of the non-bonded groups which repel each other. There are two such exponential terms, for in most sterically hindered diphenyls the repulsion is caused by two pairs of ortho substituents. The equation for E0, the activation energy for racemization, has been found for the symmetrical case by minimizing E; the constants ai, A, and ρ, and the dimensions of the diphenyl derivative appear in the expression for E0. It is also possible to derive equations for the vibration frequencies of the planar form of the sterically hindered molecule (and, therefore, find the entropy of activation); these equations are complicated by the essential degeneracy of the vibrations in question.
On the Equation of State for Gases at Extremely High Pressure
Authors: Caldirola P.
Published: January 2005

On the basis of the thermo-hydrodynamic theory of the explosive detonation—developed by Chapman, Jouguet, and R. Becker—a procedure is developed permitting the deduction of the equation of state for gaseous mixtures from explosive processes. The equation is established by starting from several sets of experimental data. In this way one can semi-empirically derive the equation of state for gases compressed up to 104−105 atmos. The results of numerical calculations are reported.
The Mercury Photosensitized Reactions of Propylene and Isoprene
Authors: Gunning H. E. , Steacie E. W. R.
Published: January 2005

An investigation has been made of the reactions of propylene and isoprene with mercury (3P1) atoms, at 30°C, in a static system. The reactions are similar in that the rates of consumption of both propylene and isoprene decrease with increasing pressure in the range of complete quenching. In addition, the quantum yields of both reactions are low. The products of the propylene reaction are liquid polymer and hydrogen, together with smaller amounts of methane, ethylene, and hexene. The principal steps in the mechanism proposed for the propylene reaction are C3H6+Hg(3P1)→C3H6*+Hg(1S0; C3H6*+C3H6→2C3H6; C3H6*→C3H5+H; H+C3H6→C3H5+H2; H+C3H6→CH3+C2H4; followed by polymerization reactions of the type C3H5+C3H6→C6H11, etc.
Stress-Time-Temperature Relations in Polysulfide Rubbers
Authors: Stern M. D. , Tobolsky A. V.
Published: January 2005

Polysulfide rubbers of various internal structures have been investigated by measurements of continuous and intermittent relaxation of stress and by creep under constant load at temperatures between 35°C and 120°C. Continuous stress relaxation measurements indicate that these rubbers approximately obey the simple Maxwellian law of relaxation of stress, which indicates that one definite type of bond in the network structure is responsible for stress decay. The activation energy for the relaxation process in each of the polysulfide rubbers is nearly the same, indicating that the same type of bond is responsible for the relaxation behavior of all the polysulfides investigated. In contrast to the hydrocarbon rubbers, oxygen is not the cause of high temperature relaxation in polysulfide rubbers, nor does heating in air at moderate temperatures for times comparable to the relaxation time produce changes in physical properties as determined by modulus or by appearance of the samples. Several possibilities regarding the mechanism of the relaxation process and the type of bond involved are considered in the light of the experimental results.
Surfaces of Solids XV First-Order Phase Changes of Adsorbed Films on the Surfaces of Solids: The Film of n-Heptane on Ferric Oxide
Authors: Jura George , Loeser Edward H. , Basford Paul R. , Harkins William D.
Published: January 2005

Two-dimensional first-order changes, in which a gaseous film of normal heptane is transformed into another phase of lower molecular area with evolution of heat, have been discovered on subphases of ferric oxide, silver, and graphite. All of the critical phenomena observed in three-dimensional systems are found to be duplicated. For n-heptane on ferric oxide the critical constants are: σc (area) 900A2 per molecule; π (film pressure) 0.45 dyne cm−1; and Tc, 29°C. The critical constants are found to depend on the nature of the solid as well as on that of the vapor. The heat of transformation at 25°C is estimated to be 12,000±5000 cal. mole−1. This value appears to be considerably higher than the 6150 cal. mole−1 required for the formation of three-dimensional liquid n-heptane from its vapor at the same temperature. The volume-pressure relations are considered for the adsorption isotherm in the case in which a second- or third-order phase change occurs.
The Thermal Conductivites of Eight Common Gases between 80° and 380°K
Authors: Johnston Herrick L. , Grilly Edward R.
Published: January 2005

Thermal conductivities of O2, N2, CO, NO, H2, He, N2O, CO2, and CH4 have been measured between 80°K and 380°K, with the potential lead type of hot wire cell developed by Taylor and Johnston. Results—which have a precision generally better than 0.1 of one percent and are believed to be accurate to ±0.5 of one percent—are tabulated for the eight gases. Comparisons with the results of other investigators are also shown in tabular form.
On the Diffusion of Vapors through Polymers
Authors: Doty Paul
Published: January 2005

The rate of permeation of a gas through a polymer as a function of temperature may be represented as P = P0e−E/RT. All available data on the permeability of gases through polymers show that for a given gas there is a linear relation between log P0 and E (the energy of activation for permeation). An explanation is offered for this apparent relationship. The effect of plasticization on permeation of water vapor is studied experimentally and it is shown that the lowering of the heat of solution is the predominant effect. From the data the entropy of solution may be calculated and interpreted as showing that water molecules dissolved in the unplasticized polymer exhibit much less freedom than when they are dissolved in plasticized polymer. Other calculations show (in agreement with Barrer) that a large number of degrees of freedom are simultaneously operative in the process of the diffusion of a gas molecule through a polymer.
Theory of Multimolecular Adsorption from a Mixture of Gases
Authors: Hill Terrell L.
Published: January 2005

By making use of the evaporation-condensation properties of liquid mixtures, the Brunauer-Emmett-Teller theory of multimolecular adsorption is extended to mixtures of gases. No satisfactory experimental data are available at the present time with which to test the theory.
A Relation between Bond Force Constants, Bond Orders, Bond Lengths, and the Electronegativities of the Bonded Atoms
Authors: Gordy Walter
Published: January 2005

A relation of the form k=aN(xAxB/d2)34+bhas been found to hold accurately for a large number of diatomic and simple polyatomic molecules in their ground states. (The average deviation of k calculated from k observed for seventy-one cases is 1.84 percent.) Here k is the bond-stretching force constant, d the bond length, N the bond order, and xA and xB are the electronegativities of the bonded atoms. If k is measured in dynes/cm×10−5 and d in Angstrom units, a and b have the values 1.67 and 0.30, respectively, for stable molecules exhibiting their normal covalencies, except those in which both bonded atoms have only one electron in the valence shell; for diatomic molecules of the alkali metals, Na2, NaK, etc., a and b are 1.180 and −0.013, respectively; for hydrides of elements having a single electron in the valence shell, 1.180 and 0.040, respectively; and for diatomic hydrides of elements having two to four electrons in the valence shell, 1.42 and 0.08, respectively. Numerous applications of the relation are made and certain exceptions are pointed out.
An X-Ray Diffraction Investigation of the Thermal Decomposition of Silver Oxalate
Authors: Griffith R. L.
Published: January 2005

A single crystal of silver oxalate was studied by x-ray diffraction during the process of thermal decomposition. The diffraction patterns indicated that some fragmentation of the single crystal occurred early in the reaction. Except for distortion, the monoclinic structure was maintained until all trace of silver oxalate disappeared. The gradual appearance of polycrystalline silver was apparent. The diffraction patterns showed that a portion of the silver assumed preferred orientations, the ratio of oriented to unoriented silver remaining constant throughout the reaction. Four different preferred orientations were found and were defined relative to the silver oxalate lattice.
Conductometric Investigation of Electrolytic Solutions in Hydrocarbons
Authors: Gemant Andrew
Published: January 2005

Conductometric investigations were made of electrolytic solutions in xylene and of a hydrocarbon oil both of which have conductivities of from 10−12 to 10−11 mho/cm at room temperature. The electrolytes introduced were composed of an organic basic and an organic acidic material, the former being an amine. A three-component system (amine, aliphatic acid, and a phenol) was generally required in order to obtain high conductivities at relatively low concentrations of electrolytes. It is shown that the effect of the phenol is only partly caused by the increase of dielectric constant; the chief process is probably a specific one. On the theory that the mechanism consists in the formation of an addition-compound that subsequently dissociates into ions, the experimental data were subjected to an analysis. It appears that generally five or more single molecules combine to form a compound and that the concentration of the compound is a small percentage of the total solute present. The results have a bearing on the problem of deterioration of insulating oils. The high conductivities of the latter, even in the presence of certain colloidal constituents, are ultimately caused by electrolytic ions of the type investigated.
The Photochemical Polymerization of Butadiene
Authors: Volman David H.
Published: January 2005

The mercury photo-sensitized polymerization of butadiene and butadiene-acetone mixtures in the gas phase, and the photochemical reactions in solutions of butadiene and acetone in hexane, were studied. Metal mirror experiments demonstrated the absence of hydrogen atoms and the presence of alkyl radicals at low pressures. The mechanism proposed for butadiene vapor postulates an activated butadiene molecule produced by collision with activated mercury and competition between deactivation by collision, predissociation into free radicals, and a collisional process to give hydrogen gas. The polymerization chain proceeds by a mechanism involving either free radicals or hydrogen atoms. In the presence of acetone vapor, the rate is increased and the increase is directly proportional to the number of free radicals coming from acetone, indicating that polymerization chains are not broken by bimolecular gas phase reaction between free radicals. The quantum yield for butadiene alone at 53-mm pressure and 43°C was 0.24. The average number of molecules reacting per free radical formed was calculated to be between 3 and 8. The liquid solution results are explained on the basis of a modified Frank-Rabinowitch hypothesis for the primary photochemical process. Activated acetone molecules are deactivated by collision with hexane, and react with acetone to yield unsaturated compounds and with butadiene to initiate polymerization. The following kinetic equation is developed for the rate of polymerization, dP/dt=(kIabs/I0)(n[C4H6]–[(CH3)2CO]), where n is the average number of molecules reacting per free radical. n is taken equal to 4.
An Electron Diffraction Investigation of Dimethylketene Dimer
Authors: Lipscomb William N. , Schomaker Verner
Published: January 2005

An electron diffraction investigation of dimethylketene dimer confirms the 2,2,4,4-tetramethylcyclobutadione-1,3 structure. The following parameters were determined for the symmetrical model: C–C (ring)=1.56±0.05A, C–CH3=1.54±0.05A, C=O=1.22±0.04A, ∠C–CO–C=93°±6°, and ∠CH3–C–CH3=111°±6°. The limits of error assigned to the angles apply only if simultaneous variation is excluded; otherwise much larger limits must be assigned. A notable feature of the structure is the large temperature factor which must be ascribed to the interatomic distances greater than 3A. The relation of this temperature factor to the unusually large atom polarization is discussed in terms of the probable amplitudes of the pertinent modes of vibration of the molecule.
The Heats of Solution of Hexamethylbenzene, Cetyl Alcohol, and Dicetyl in Related Liquids; Heats of Fusion by an Extrapolation Process
Authors: Parks George S. , Rowe Robert D.
Published: January 2005

The heats of solution of crystalline hexamethylbenzene, cetyl alcohol, and dicetyl in various related liquids have been obtained at 25°C. Benzene, toluene, xylene, and mesitylene have been used as solvents for hexamethylbenzene, and a value for the heat of fusion of this substance has been deduced from these heats of solution by an extrapolation process. Similarly, a series of alcohols (methyl, ethyl, n-butyl, n-heptyl, and n-dodecyl) have been used for the solution of cetyl alcohol. Solubility limitations, however, made it impractical to employ any liquid paraffin except n-heptane in the case of dicetyl. The heats of fusion at 25°C, as estimated from the present solution experiments, are per gram: hexamethylbenzene, 29.0±0.3 cal.; cetyl alcohol, 48.2±0.7 cal.; and dicetyl (dotriacontane), 58.7±1.2 cal.
The Near Ultraviolet Absorption Spectrum of Toluene Vapor
Authors: Ginsburg Nathan , Robertson W. W. , Matsen F. A.
Published: January 2005

The experimental work of Savard and the theoretical work of Sponer on the absorption spectrum of toluene vapor is extended. A spectrum of 209 bands was observed with partial resolution of the fine structure. A tentative analysis is given based on ground state frequencies 514, 620, 785, 1003, 1012, 1176, and 1209, which correlate completely with Raman data; on excited state frequencies, 456, 528, 751, 932, 964, and 1186; and on difference frequencies 59 and 178 cm−1. Assuming C2v symmetry, all frequencies below 1300 cm−1 of symmetry class A1 appeared in 1–0 transitions and with one exception in 0–1 transitions. In addition, a vibrational frequency of symmetry class B1, deriving from an εg+ vibration in benzene, appeared strongly both in the ground and excited state.
The Force Constants of Ozone
Authors: Glockler George , Matlack George
Published: January 2005

A general valency force field treatment has been applied to the ozone molecule, in which it has been possible to obtain values for all four force constants. The values obtained, using a fundamental frequency assignment of Penney and Sutherland, are compared with values obtained from other assignments. In the light of present knowledge concerning the structure of the ozone molecule, the values used by Penney and Sutherland (ω1 = 1043, ω2 = 710, ω3 = 1740 cm−1) are the most consistent, and the force constant of the oxygen-oxygen bond agrees better with the value predicted by Badger's rule than do the others. The oxygen-oxygen bond force constant in ozone lies in the range 0.75 to 0.99 megadyne.
Some Nonequilibrium Properties of a Bose System of Hard Spheres at Extremely Low Temperatures
Authors: Wu Tai Tsun
Published: January 2005

The pseudopotential method is used to study a special type of flow for a Bose system of hard spheres. In the first-order approximation, the wave function of the entire system is assumed to be the product of identical single-particle wave functions, which in general are time-dependent. Such a flow is necessarily irrotational, and the single-particle wave function satisfies a Schrödinger equation with a nonlinear self-coupling term. On the basis of this equation of motion, the following properties of the Bose system are discussed: the effect of the rigid wall, the moment of inertia, the compressional wave, and a type of ``vortex filament.'' In the second-order approximation, the wave function of the system is expressed in terms of two functions such that one of them describes the single-particle state suitable for most of the particles while the other one describes the pair excitations. The much more complicated equations of motion are found, but in this approximation the flow is no longer strictly irrotational. The compressional waves are also studied in the second-order approximation.
Some Counting Theorems in the Theory of the Ising Model and the Excluded Volume Problem
Authors: Sykes M. F.
Published: January 2005

The problem of the exact enumeration of self-avoiding random walks on a lattice is studied and a theorem derived that enables the number of such walks to be calculated recursively from the number of a restricted class of closed graphs more easily enumerated than the walks themselves. The method of Oguchi for deriving a high-temperature expansion for the zero-field susceptibility of the Ising model is developed and a corresponding theorem enabling the successive coefficients to be calculated recursively from a restricted class of closed graphs deduced. The theorem relates the susceptibility to the configurational energy and enables the behavior of the antiferromagnetic susceptibility at the transition point to be inferred.
Use of Series Expansions for the Ising Model Susceptibility and Excluded Volume Problem
Authors: Domb C. , Sykes M. F.
Published: January 2005

The present paper discusses the problem of making the most effective use of the coefficients of series expansions for the Ising model and excluded volume problem in estimating critical behavior. It is shown that after initial irregularities the coefficients appear to settle down to a smooth asymptotic behavior. Alternative methods of analysis are considered for the provision of a steady series of approximations to the critical point. Numerical conclusions are drawn for particular lattices for which additional terms have recently become available.
Molecular Collisions. II. Diatomic Molecules
Authors: Gioumousis George , Curtiss C. F.
Published: January 2005

A set of coupled integral equations describing the collisions of diatomic molecules is developed by exploitation of the properties of the irreducible representations of the three-dimensional rotation group. An expansion of the cross section in spherical harmonics is described, and its virtues argued.
A Note on k-Commutative Matrices
Authors: Robinson D. W.
Published: January 2005

Let A and B be square matrices over a field in which the minimum polynomial of A is completely reducible. It is shown that A is k commutative with respect to B for some non-negative integer k if and only if B commutes with every principal idempotent of A. The proof is brief, simplifying much of the previous study of k-commutative matrices. The result is also used to generalize some well-known theorems on finite matrix commutators that involve a complex matrix and its transposed complex conjugate.
New Possibilities for a Unified Field Theory
Authors: Israel W. , Trollope R.
Published: January 2005

The introduction of nonsymmetric gik in unified field theories of the Einstein-Schrödinger type is open to the objection, on group-theoretical grounds, that the symmetric and antisymmetric parts transform independently. This objection does not apply to the use of nonsymmetric Γikμ, since these quantities are irreducible under the ``extended group,'' consisting of the point transformations and the Einstein λ transformations.

We consider a theory based on symmetric gik and nonsymmetric Γikμ. The Lagrangian L is assumed to depend only on gik and the contracted curvature tensor Rik (this insures the λ invariance and transposition invariance of the theory). For simplicity, we suppose further that L involves Rik rationally and, at most, quadratically.

The resulting theory is able to account satisfactorily for the main feature of gravitation, electromagnetism, and their interaction. In particular, the theory yields the correct equations of motion for charged masses. The electromagnetic tensor is associated with the skew part of Rik, and the λ transformations correspond roughly to the gauge transformations of electrodynamics.
Isoperimetric and Other Inequalities in the Theory of Neutron Transport
Authors: Dresner Lawrence
Published: January 2005

Some isoperimetric and other inequalities occurring in the one-velocity theory of neutron transport are derived. The quantities involved in these inequalities all refer to bare solids with isotropic scattering and are: the critical multiplication, the first-collision probability, the non-escape probability, and the buckling. The inequalities proved provide upper and lower bounds for the quantities considered, and numerous examples of the estimation of these quantities in cases not readily amenable to direct calculation are given.
A Lattice with an Unusual Frequency Spectrum
Authors: Rubin Robert J. , Zwanzig Robert
Published: January 2005

The lattice is a special rooted Cayley tree, generated by N successive m-fold branchings. With each point of the tree are associated a mass M and a position coordinate xi. All end points are held fixed at xi=0. The potential energy is V=½ Σi,j Kij(xi−xj)2, where Kij=K if i and j are connected neighbors and neither is an end point, Kij=αK if i and j are connected neighbors and either is a branch tip point, and Kij=0 if i and j are not connected neighbors. The allowed frequencies of vibration are obtained for two different cases: In the first case all springs are identical (α=1), and in the second case the springs connecting interior points to the branch tips are cut (α=0). In the case in which all force constants are the same, the allowed frequencies of vibration, in the limit of infinite N, are given by ω(r) = (K/M) ½[m+1 − 2m½ cosrπ]½, where r is any rational number between zero and one. The fraction of all normal modes having precisely the value ω(r) is ρ[ω(r)] = (m − 1)2 / (mq − 1), where r is expressed as the ratio r=p/q of relatively prime integers p and q. The frequency spectrum is dense within the interval (m½ − 1, m½+1); and ρ[ω] is discontinuous at every ω for which it does not vanish.
Electrical Conduction in a Noncircular Rod
Authors: Pipkin A. C. , Rivlin R. S.
Published: January 2005

The general constitutive equations for galvanomagnetic effects in isotropic materials are applied to the study of electrical conduction in rods. It is shown that, in general, rectilinear current flow is not possible, unless the rod has a circular cross section or is an infinite parallel-sided slab.
Transient Response of a Dipole Antenna
Authors: Wu Tai Tsun
Published: January 2005

The current distributed for a dipole antenna driven by a step-function voltage is found shortly after the switch-on of the voltage.
A Convergent Perturbation Expansion in First-Quantized Electrodynamics
Authors: Reiss Howard R.
Published: January 2005

It is shown that a real physical problem exists which, when calculated in first-quantized electrodynamics, possesses a convergent perturbation expansion. The result is demonstrated by proving the analyticity in a region of nonzero radius about the origin in the complex coupling-constant plane, of the transition probability for pair creation by two electromagnetic fields. Some singularities in the complex plane are located, which limit the radius of convergence only for a discrete set of values for the energies of the electromagnetic fields which define the problem.