bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relative Rates of Photo-Chlorination of CHCl3 and CDCl3
Authors: Newton T. W. , Rollefson G. K.
Published: January 2005

The relative rates of photo-chlorination of chloroform and deuterochloroform have been determined in the temperature range of −20° to 180°C. The ratio of the rate constants for the two reactions can be fitted by the equation: k1/k2=1.4±0.2 exp(710∓90/RT).This result is discussed in terms of Eyring's absolute reaction rate theory and also in terms of an alternative mechanistic explanation. The observed difference in activation energy is accounted for in terms of the zero-point energies of the normal molecules and the activated complexes.

It was found that some deuterochloroform was produced when chloroform was chlorinated in the presence of deuterium chloride. This result indicates that the reactionHCl+CCl3=CHCl3+Clmust occur to some extent in the gas-phase chlorination of chloroform, contrary to the conclusions of Schumacher and Wolff. It was also found that appreciable amounts of hexachloroethane were formed in the reaction. Hence, it is concluded that the formation of this substance must be an important chain-terminating step in the reaction mechanism.
Molecular Orbital Calculations of Vibrational Force Constants. II. The Ring-Twisting Constants of Benzene
Authors: Crawford Bryce L. , Parr Robert G.
Published: January 2005

Two out-of-plane bending force constants of the C6 framework of benzene are calculated by the method of antisymmetric molecular orbitals, and the values obtained compared with those previously determined by Miller and Crawford from spectroscopic data.
Statistical Mechanics of Adsorption. VII. Thermodynamic Functions for the B.E.T. Theory
Authors: Hill Terrell L.
Published: January 2005

As an application of the thermodynamic methods discussed in an earlier paper, thermodynamic functions are calculated from the B.E.T. statistical model.
Mass Spectrometric Study of a Mixture of Deuterated Acetaldehydes
Authors: Brinton Robert K. , Blacet Francis E.
Published: January 2005

An investigation of the composition of samples of deuterium containing acetaldehyde was made by mass spectrometric methods. The complete determination of the relative abundance of all possible heavy acetaldehyde species was accomplished by combining data from the direct mass spectrometric analysis with information on the relative amounts of heavy methyl iodides produced when the gaseous heavy acetaldehyde mixture was photolyzed with ultraviolet light in the presence of iodine vapor. The distribution of the various acetaldehydes in the mixture was about 80 percent CH3CDO and 17 percent CH3CHO with small amounts of acetaldehydes of higher deuterium content. The mass spectrum of the acetaldehyde mixture was corrected to give the spectrum of the single species, CH3CDO. Inspection of the corrected spectrum indicated that on impact by 60 electron-volt electrons the split of the C–H bond of CH3CHO is more probable than the corresponding split of C—D bond in CH3CDO in agreement with the findings of Delfosse and Hipple who first reported this difference in the behavior of C–H and C—D bonds for cis and trans ethene−1,2d2. The formation of formyl positive ion in the case of CH3CDO is evidently by a clean split of the C–C bond with little exchange of hydrogen and deuterium between carbon atoms at the time of electron impact. The formation of methyl positive ion, on the other hand, is accompanied by a large interchange of hydrogen and deuterium between carbon atoms.
Isomer Distribution in Hydrocarbons from the Fischer-Tropsch Process
Authors: Weller Sol , Friedel R. A.
Published: January 2005

The isomer distribution experimentally found for the saturated-hydrocarbon products (pentane to octane range) from a cobalt Fischer-Tropsch catalyst have been deduced from probability considerations. With certain restrictions, it is assumed that the carbon skeleton is built up by addition to any terminal carbon atom (for which the a priori probability has a constant value a) or to any penultimate carbon atom (with a priori probability b). Values of a and b, determined from experimental data, led to deduced isomer concentrations in each molecular-weight cut agreeing with experimental concentrations with an average deviation of 0.7 percent. Peculiarities in the observed isomer distribution were also reproduced.
Diamagnetic Susceptibilities of Mercuric and Mercurous Ions
Authors: Prasad Mata , Dharmatti S. S. , Ghose A. K.
Published: January 2005

Magnetic susceptibilities of a number of pure mercuric and mercurous salts of inorganic and organic acids have been measured and it has been shown that Ikenmeyer's relation does not hold true in these compounds. A linear relation has been established between the molecular susceptibilities of salts of Mg, Zn, Cd, and Hg (ic) containing the same anion and the number of electrons contained in the cations. The significance of this relation is discussed in detail primarily with a view to finding out the susceptibilities of mercuric and mercurous ions.
Statistical Mechanics of Swelling of Network Structures
Authors: Flory Paul J.
Published: January 2005

Inaccuracies in previously published theories dealing with the swelling of network polymers in solvents are pointed out. The treatment of Flory and Rehner, based on the tetrahedral model, is overly restrictive and leads to an entropy of swelling which is too small. A more recent treatment of Kuhn, Pasternak, and Kuhn introduces an error in the opposite direction. In the present paper the entropy of swelling a network of any degree of connectivity, or functionality f, is derived in a manner which avoids these inaccuracies. Corrected relationships are given for the partial molal-free energy of dilution, swelling equilibrium and the influence of deformation on swelling equilibrium. These differ appreciably from those previously given when the degree of interlinking (i.e., concentration of cross linkages if f=4) is large and the equilibrium degree of swelling therefore is small. Previous expressions for elastic deformation at constant volume are unaffected.
An Electron Diffraction Investigation of the Structures of Neopentyl Chloride and Silico-Neopentyl Chloride: The Determination of Intensities through the Use of a Rotating Sector
Authors: Hastings J. M. , Bauer S. H.
Published: January 2005

Constructional details and operational data on an electron diffraction apparatus, in which a rotating sector has been incorporated, are presented. Its range of application and limitations are listed, and methods for the reduction of microphotometer records are discussed.

Electron diffraction photographs of neopentyl chloride and silico-neopentyl chloride were taken with and without sectors. Their structures were deduced by a combination of the visual and photometric procedures. Attempts were made to estimate quantitatively the equivalent temperature factors for libration about the C–C and Si–C bonds. Best values for the interatomic distances and their possible interpretations are presented in the concluding section.
Spectroscopic Studies of Rotational Isomerism. V. The Infra-Red Absorption Spectra of Six Solid Hydrocarbons in the Region 1600–650 cm−1
Authors: Axford D. W. E. , Rank D. H.
Published: January 2005

The infra-red absorption spectra of six hydrocarbons have been measured at low temperatures. As with the Raman spectra, a considerable degree of simplification occurs on freezing, due to the existence of only one rotational isomer in the solid state. It has not proved possible to obtain accurate values of the energy differences between the isomers from this data. The possible ways of obtaining energy difference from spectroscopic data are discussed.
Light Scattering Arising from Composition Fluctuations in Multi-Component Systems
Authors: Kirkwood John G. , Goldberg Richard J.
Published: January 2005

A general theory of Rayleigh scattering due to composition fluctuations in multi-component systems is developed with the aid of the grand canonical ensemble of Gibbs. It reduces to the usual expression for systems of two components, but contains previously neglected terms arising from thermodynamic interactions between solutes in systems of more than two components. The theory is used to interpret the turbidity measurements of polystyrene in benzene-methanol mixtures of Ewart, Roe, Debye, and McCartney.
Quantitative Studies of Radiation-Induced Reactions in Aqueous Solution. I. Oxidation of Ferrous Sulfate by X- and γ-Radiation
Authors: Miller Nicholas
Published: January 2005

A study has been made of the oxidation of ferrous ions in 0.8N sulfuric acid solution by x- and γ-radiation in different types of system and using different energies of incident radiation. The conclusion is reached that simple modes of dosimetry, such as have been used in previous determinations of the ionic yields for a number of reactions induced by radiation in aqueous systems, are adequate if accuracy within 20 percent is all that is required. For greater precision, more rigorous methods have to be adopted, and using such a method, the ferrous sulfate system has been calibrated with a view to its possible use as a mode of integral dosimetry for aqueous media. Some speculations as to the mechanism of this particular reaction are included.
Valence Force Displacement Coordinates for Systems in Which the Angles Deviate from the Ideal
Authors: Torkington P.
Published: January 2005

Sets of valence force displacement coordinates are given which are applicable to practically any system. The coordinates for ideal bonding-angles arise as special cases. The derived symmetry coordinates for a few typical systems are obtained, and it is shown how the force constants can be corrected for small deviations of the angles from their ideal hybrid-bond values.
Ionization and Dissociation by Electron Impact: Cyanogen, Hydrogen Cyanide, and Cyanogen Chloride and the Dissociation Energy of Cyanogen
Authors: Stevenson D. P.
Published: January 2005

The appearance potentials of CN+ in the mass spectra of HCN and (CN)2 have been remeasured and found to be 19.36±0.2 and 20.31±0.2 ev, respectively. Combination of the appropriate thermochemical data with the difference between these energies yields, D(NC–CN) = 6.88−2E(Z) ev where Z is the state of the CN radical either X2Σ+ or A2Πi, that accompanies CN+ from (CN)2, and E(X2Σ+) = 0.00 ev and E(A2Πi) = 1.13 ev. The appearance potential of Cl+ in the mass spectrum of ClCN has also been measured and found to be 17.81±0.2 ev, which value gives D(NC–CN) = 6.92−2E(Y) when combined with the spectroscopic ionization potential of the chlorine atom and the necessary thermochemical data. Here Y is the state of the CN radical that accompanies Cl+ from ClCN. In order that the two determinations of D(NC–CN) be consistent it is necessary that Y = Z and then the two permissible values of D(NC–CN) are 6.90±0.2 ev (Y = Z = X2Σ+) or 4.64±0.2 ev (Y = Z = A2Πi). These results do not permit a choice between White's determination, 6.3±0.2 ev, and Pauling's estimate, 3.9±0.6 ev, but do serve to eliminate from further consideration the determination by Kistiakowsky and Gershinowitz, 3.3 ev. Neither value is compatible with the 5.2 ev suggested by Glockler. However, electron impact data on ethylene and methylene radical give 5.6 ev as the upper limit to energy of dissociation of ethylene into two methylene radicals, and this can be taken as an upper limit to the dissociation energy of cyanogen, suggesting the lower of the two possible values of D(NC–CN) to be correct. Corresponding to this lower value of D(NC–CN), 4.64±0.2 ev, the dissociation energies of H–CN and Cl–CN are 4.80±0.1 and 3.66±0.1 ev, respectively, and the ionization potential of CN is 14.55±0.2 ev.

The specific intensities of the various ions in the mass spectra of (CN)2, HCN, and ClCN characteristic of 75-volt ionizing electrons are given with reference to that of A+ in the argon mass spectrum.
The Cataphoresis of Spherical Particles in Strong Fields
Authors: Booth F.
Published: January 2005

The problem of determining the rate of cataphoresis of a solid spherical particle in an electrolyte when relaxation effects are neglected, is solved completely by using Oseen's equations. The bearing of the results on the usual methods of finding zeta-potentials from cataphoretic velocities is discussed.
The Accommodation Coefficients of Gases on Platinum as a Function of Pressure
Authors: Thomas Lloyd B. , Brown Robert E.
Published: January 2005

The accommodation coefficients of nine gases on platinum at various temperatures in six different tubes are presented as a function of pressure. In all cases the accommodation coefficients show a constant value as the pressure is lowered toward zero, which is in contradiction to results reported by Amdur and co-workers. Reasons for disagreement are suggested and criticism of an earlier paper from this laboratory is answered. Presumably specially reliable values of the accommodation coefficients of argon and krypton taken in Tube B are given and this tube and method of operation are described in detail.
Harmonic Oscillator Contributions to the Thermodynamic Functions
Authors: Torkington P.
Published: January 2005

Tables giving the harmonic oscillator contributions to the specific heat, internal energy and free energy functions directly, for frequencies in the range 100 to 3600 cm−1, at nine standard temperatures, have been drawn up.
The Theory of Ionic Solutions
Authors: Mayer Joseph E.
Published: January 2005

The virial development for the osmotic pressure of a solution may be used, if the potentials of average force of the solute molecules at infinite dilution are known, to compute the deviations from perfect solution behavior. The expression for the logarithm of the activity coefficient can thus be obtained as a sum of coefficients multiplied by powers of the concentration. For an ionic solution, with 1/R2 forces, the series is only conditionally convergent. By summing certain additive terms occurring in the coefficients over all powers of concentration convergence can be attained.

The integrations necessary to obtain terms correct up to and including c32 are performed. The results are given in terms of certain functions which can readily be computed.
The Structure and Dipole Moment of Isothiocyanic Acid
Authors: Beard C. I. , Dailey B. P.
Published: January 2005

``Thiocyanic acid'' in the vapor state has been found to be at least 95 percent HNCS. From an analysis of the microwave rotational spectrum the following bond distances and bond angle were determined rH–N=1.01A (assumed), rN–C=1.218A, rC–S=1.557A, H–N–C angle 136°. Analysis of the Stark spectrum indicates that the component of dipole moment along the molecular figure axis is 1.72 D. Stark components from transitions forbidden in the zero-field spectrum have been observed.
Asymmetry of Inner Electron Distributions in Homonuclear Diatomic Molecules
Authors: Reiss Howard , Saltsburg Howard
Published: January 2005

Disturbances in the distributions of inner shell electrons due to bond formation in homonuclear diatomic molecules have been investigated using a Fermi-Thomas type statistics. In the majority of molecules examined the disturbance seems to penetrate only to the shell directly beneath the valence shell.

Plots of the number of electrons disturbed versus atomic number are periodic, the disturbance being less for the alkali molecules than for the halogens. In any one group, these plots are remarkably linear. This behavior has permitted us to calculate the bond distance in Rb2. It is found to be 4.28A. This value is to be compared with the distance 4.32A between nearest neighbors in the metal.
Kinetics of OH Radicals from Flame Emission Spectra. II. Rotational and Vibrational Distribution Functions and Temperature Determinations in the 2Σ+—2Π Transition of OH
Authors: Shuler K. E.
Published: January 2005

Rotational and vibrational distribution functions for a rotating oscillator are developed for a steady state with non-equipartition of energy such as might be found for electronically excited species in a flame. Methods are described for the separate spectrocsopic determination of rotational and vibrational equilibria and ``temperatures'' for the case of thermal equilibrium and for the case of a non-equipartition distribution of energy. These methods are applied to the study of electronically excited OH radicals in an equimolar oxynatural gas (88 percent CH4) flame. Rotation-vibration equilibrium with a rotation-vibration temperature of ∼2550°K was found. Analysis of the data indicates that the vibrational transition probabilities for the 2Σ+—2Π transition calculated in Part I of this paper are accurate to about the 10 percent claimed in that communication.
Infra-Red and Raman Spectra of Fluorinated Ethanes II: 1,1,1-Trifluoroethane
Authors: Nielsen J. Rud , Claassen Howard H. , Smith D. C.
Published: January 2005

The infra-red absorption spectrum of gaseous 1,1,1-trifluoroethane between 2 and 23μ has been investigated with a prism spectrometer of high resolution. The Raman spectrum of CF3–CH3 in the gaseous state has been photographed with a three-prism glass spectrograph of linear dispersion 15A/mm at 4358A. The 12 fundamental frequencies have been assigned, and the spectra have been interpreted in detail. Thermodynamic functions have been calculated. A value of 3290 cal./mole has been obtained for the potential barrier opposing internal rotation.
Lennard-Jones and Devonshire Equation of State of Compressed Gases and Liquids
Authors: Wentorf R. H. , Buehler R. J. , Hirschfelder J. O. , Curtiss C. F.
Published: January 2005

The reduced equation of state for compressed gases and liquids is computed according to the theory of Lennard-Jones and Devonshire for a large number of temperatures and densities. The corrections due to gas imperfection of internal energy, specific heat, and entropy as well as the compressibility factor (pv/RT) are expressed in terms of reduced variables. The calculations were made by punched-card methods. A comparison is made between experiment and theory. It is shown that the theory of Lennard-Jones and Devonshire is unsatisfactory at densities near the critical point and lower but improves at higher densities becoming better for normal liquids. Such results were to be expected from the nature of the cell or free-volume method.
The Effect of Isotopic Substitution on Mass Spectra of Molecules
Authors: Schaeffer Oliver A.
Published: January 2005

A general method for calculating the effect of isotopic substitution on mass spectra is presented. The calculation is based on the notion that the various fragment ions, formed by electron impact on a molecule, are produced by a Franck-Condon mechanism. It is assumed that those bonds will break which possess more potential energy than bond energy at the instant of ionization. The mass spectral data for a molecule are used in conjunction with the ground-state vibrational wave function to evaluate critical bond distances (distances for which the potential energy equals the bond energy). Then the mass spectral pattern for isotopic molecules can be predicted from a knowledge of the ground-state vibrational wave function of the isotopic molecule. The method is applied to the diatomic molecules N14N14, N14N15, N15N15, and C12O16, C13O16. The predicted values compare favorably with previously observed results, however, experimental errors obscure a sharp test of the predictions for these cases. New experimental values are presented for the ratios C13+/C13O216+ and C12+/C12O216+ from carbon dioxide and compared with predictions. Good agreement is found between ratios extrapolated to high ion accelerating voltage and predicted ones.
The Infra-Red and Raman Spectra of Cyclopentane, Cyclopentane-d1, and Cyclopentane-d10
Authors: Miller Foil A. , Inskeep Richard G.
Published: January 2005

The infra-red and Raman spectra of cyclopentane, cyclopentane-d1, and cyclopentane-d10 have been determined for the purpose of establishing the symmetry of cyclopentane. D5h selection rules are found to hold very well. This does not constitute a rigorous criterion for structure in this case, however, because drastic alteration of the symmetry by substituting groups such as D, OH, CH3, or Cl for a hydrogen atom does not appreciably increase the complexity of the spectra. The data have provided two strong arguments against a D5h structure. (1) An assignment could not be made which simultaneously satisfied the product rule and the expected band contours. (2) The entropy of the vapor demands a low frequency (near 140 cm−1 for the assignment in this paper) if the symmetry is D5h. This is completely incompatible with the heat capacity of the solid.

It is concluded that cyclopentane definitely does not have D5h symmetry. The actual geometry of the molecule is still not known. It is shown that a rigid structure of symmetry Cs, C2, or C1 is consistent with the available data. A decision between this and Kilpatrick, Pitzer, and Spitzer's model with a puckered ring and a pseudorotation in place of one of the genuine normal vibrations cannot be made at this time.

Analogous spectroscopic results for perfluorocyclopentane are mentioned briefly for comparison. This molecule is definitely non-planar.

The method of preparation of the deuterium compounds is given. A Pd-on-charcoal catalyst is described which promises to be useful in other hydrogen-deuterium exchange reactions.
V-Centers in Alkali Halides
Authors: Casler Ruth , Pringsheim Peter , Yuster Philip
Published: January 2005

V-centers are defined as stabilized positive holes. The peak wave-lengths of three V-bands of KCl, KBr, and NaCl are listed. Most of the paper deals with KCl, but the results are typical for KBr and NaCl as well. Experimental data are given concerning the conditions under which the various V-bands are obtained and their unequal stability with regard to bleaching by light and temperature. Crystals irradiated at various temperatures and observed at room temperature show superpositions of the V2- and V3-bands with relative intensities depending greatly on the temperature at which the crystals were irradiated and on the nature of the primary radiation. The V1-band can be observed only at temperatures below −100°C. These data are compared with those published by other investigators, and some remarks are made concerning the possible mechanisms which are responsible for the various phenomena.
I. The Vaporization of Strontium Oxide
Authors: Moore George E. , Allison H. W. , Struthers J. D.
Published: January 2005

The vapor pressure of SrO was measured by studying the product evaporated from platinum filaments coated with SrO. Most of the experiments employed radiactive isotopes.* The possibility of systematic error caused by chemical reduction of the oxide or by its thermal dissociation is discussed. A value of λ0, the heat of evaporation at 0°K computed from the results, is used to evaluate precision and to derive a vapor-pressure equation.
II. The Reduction of SrO by Tungsten in Vacuum
Authors: Moore George E. , Allison H. W. , Morrison James
Published: January 2005

It is shown that in the temperature range 1150–1550°K, SrO is reduced by tungsten in vacuum. Both the rate of the reaction and its equilibrium constant can be calculated, giving values in substantial agreement with the experiments, which were performed under conditions such that both could be measured. The use of radioactive isotopes simplified the experimental work.
The Small-Angle Scattering of X-Rays by Nitrogen
Authors: Wild Robert L.
Published: January 2005

An experimental study has been made of the scattering of x-rays by nitrogen at various pressures and temperatures in the general region of the critical point. Particular attention was given to the scattering at small angles. Copper Kα-radiation used with a single-crystal spectrometer and narrow slits provided the means of attaining low values of sinθ/λ where 2θ is the scattering angle and λ the wave-length of radiation. A qualitative demonstration of the effect of pressure and temperature upon the small-angle scattering from a fixed volume of sample was made by observing at a fixed angle the amount of scattering from the sample as it was made to approach and then cross the liquid-vapor transition curve. At 29 selected conditions of pressure and temperature, more complete patterns were taken in an attempt to make a quantitative application of theoretical expressions to obtain values of the isothermal compressibility and the sizes of regions of inhomogeneity which give rise to the small-angle scattering. Values of compressibility from this work are roughly comparable to those obtained by other methods. The regions of inhomogeneity are found to be small at low temperatures, and they increase in size as the P—T conditions approach the critical region. Typical values for the radii of the regions of inhomogeneity are found to be 3.8A at 115°K and 18.7 atmospheres, and 8.1A at 128°K and 36.8 atmospheres.
Factors Influencing Bond Dissociation Energies
Authors: Szwarc M.
Published: January 2005

The calculations leading to estimates of resonance energies of various molecules and radicals are analyzed and the ambiguities involved are stressed. It is suggested that an alternative approach to problems of molecular energetics may be provided by analyzing the variations in bond dissociation energies. Consideration of bond dissociation energies leads to estimates of ``experimental resonance energies'' of radicals, and to an evaluation of a ``strengthening effect'' influencing the undissociated molecule. The new approach is one of several possible variants which might be used to arrive at a better understanding of energetic relationships in molecules.
Structural Investigations by Means of Nuclear Magnetism. II. Hindered Rotation in Solids
Authors: Gutowsky H. S. , Pake G. E.
Published: January 2005

The experimental absorption line widths, for nuclei with spin 1/2, at nuclear magnetic resonance are given as a function of temperature for a number of molecular crystals. Temperatures ranged from 90°K to the melting points of the compounds. In some cases it has been possible to relate observed line structure and transitions in the line width to the existence and frequency of certain types of hindered rotational motion in the solid state. These deductions are based on mathematical considerations of the quantitative effect of such motions on the structure and second moment of an absorption line. It is emphasized that relatively low frequency motion of the order 105 cycles/second suffices to narrow the width of an absorption line from its value in the absence of that motion.

1,2-dichloroethane, 1,1,1-trichloroethane, and perfluoroethane were found to have line-width transitions coinciding with changes in crystal form and anomalies in the heat capacity. In 1,2-dichloroethane and perfluoroethane these transitions correspond to rotational motion about the long axis of the molecule. 1,1,1-trichloroethane has a line-width transition corresponding to this type of motion, but the heat capacity anomaly and change in crystal form coincides with a further small decrease in the line width to that characteristic of the liquid. A number of molecules including acetonitrile, methyl iodide, nitromethane, dimethyl mercury, and ammonia have absorption lines at 90°K corresponding to molecular rotation about the C3 figure axis. Various other data and interpretations are presented for 2,2-dimethyl propane, methanol, ethanol, acetone, methylamine, and the ethyl halides. The possibility of estimating the potential barriers hindering rotation in solids from the line-width transitions is discussed.
The Thermodynamics of Flow Systems
Authors: Curtiss Charles F. , Hirschfelder Joseph O.
Published: January 2005

The rate of change of entropy in a flow system is evaluated explicitly taking into account heat conductivity, viscosity, diffusion, and chemical reactions. The equations are developed rigorously from the kinetic theory of gases.
Short-Lived Fission Products. II. Cs139 and Cs140
Authors: Sugarman Nathan , Richter Harold
Published: January 2005

Half-life values have been obtained for Cs139 and Cs140 by extraction of the Ba descendent activities from cesium silicotungstate precipitates. The half-life of Cs139 was found to be 9.5±0.2 min. by this technique and that of Cs140, 66±2 sec. The value for the Cs139 half-life was confirmed by observation of a Cs sample isolated directly from irradiated uranyl nitrate.
An Experimental Determination of the Distribution of the Radon Decay Products in a Gas-Filled Spherical Vessel
Authors: Maxwell Charles R. , Henri Victor P. , Peterson Dorothy C.
Published: January 2005

The distributions of RaC and of (RaA+RaB) between the walls and the gaseous phase of a spherical vessel filled with a gas-radon mixture were determined by the analyses of decay curves of the gamma-activity of the radon decay products left on the walls of the vessel when it was rapidly evacuated. The distributions of RaA and RaB were determined from these data. The effects of the size of the flask, the pressure of the gas, and the type of gas upon these distributions were investigated. It is suggested that the distributions of RaA and RaB when expressed as a function of the distribution of RaC are independent of these variables. The distributions in benzene and in carbon dioxide are reported.
Line Intensities and Absorption for the 15-Micron Carbon Dioxide Band
Authors: Kaplan Lewis D.
Published: January 2005

Thorndike's value of 560×1010 cycles per centimeter-atmosphere for the total intensity of the 15-micron carbon dioxide band is used to calculate the line intensities at one atmosphere and 300°K. Calculation of absorption results in good agreement with published absorption curves by Martin and Barker. Absorption for 203 millibars and 218°K is recalculated, correcting previous errors and using better approximations.
Primary Step in the Mercury Photo-Sensitized Decomposition of Propane and of Hydrogen
Authors: Masson C. R. , Steacie E. W. R.
Published: January 2005

An attempt has been made to obtain resonance emission of HgH bands in propane-mercury mixtures illuminated with λ2537. It is concluded that if HgH is formed in the primary step in the photo-sensitized decomposition of paraffins, it must possess excess energy and largely dissociate immediately.

Further experiments with mercury-hydrogen mixtures illuminated with λ2537 have also been made, and the mechanism of the production of excited HgH molecules is discussed.
An Upper Limit to the Metastability of Supersaturated Vapors
Authors: Benson Sidney W. , Gerjuoy Edward
Published: January 2005

A thermodynamic criterion for (mechanical) instability is applied to the condensation of supersaturated vapors. Values of the maximum thermodynamic compressibility of a vapor as a function of temperature are calculated from the Van der Waals' and Berthelot Equations of State and from a newly developed, modified equation. In all cases, the upper limits predicted lie above the reported experimental values. With the exception of the Van der Waals' equation the predicted values appear much too high. The bearing of these results on the utility of the same thermodynamic criterion for estimating maximum tensile strength of liquids is discussed.
Rotation-Vibration Spectra of Diatomic and Simple Polyatomic Molecules with Long Absorbing Paths III. The Spectrum of Cyclopropane (C3H6) from 2.3 to 0.6μ
Authors: Sinha S. P.
Published: January 2005

The absorption spectrum of cyclopropane has been investigated under high resolution (21-ft. grating) in the photographic infra-red and under low resolution (with a photoelectric infra-red spectrometer) in the region 1.2 to 2.3μ with absorbing paths up to 1760 meters. A large number of overtone and combination bands, about 150, have been found. Provisional vibrational assignments of nearly all the strong bands from 2.3 to 1.3μ are given. For the weaker bands no unique assignments are possible.

The parallel band at 10970A has been resolved and its rotational structure has been analyzed. The moment of inertia in the lower state is found to have the value IB=42.15×10−40 g cm2.
The Behavior of Glass Electrodes in Acid Solutions
Authors: Sinclair Edward E. , Martell Arthur E.
Published: January 2005

Negative glass electrode errors were measured for solutions of hydrochloric acid and sulfuric acid with soft, intermediate, and hard glasses. While all the glasses measured showed negative errors, in general, the greatest deviations occurred with the soft glasses and intermediate glasses. The errors were very much greater in hydrochloric acid than in sulfuric acid solutions. The deviations observed were too great to be accounted for by the reduced activity of water alone, and were probably due in part to participation of the anion in the electrode process.
Paramagnetic Susceptibilities and Electronic Structures of Aqueous Cations of Elements 92 to 95
Authors: Howland Jerome J. , Calvin Melvin
Published: January 2005

Magnetic susceptibilities per gram atomic weight of elements 92 to 95 in most of their oxidation states were measured at 20°C on 0.1 ml of solution which was 0.005 to 0.09M in heavy element. The values obtained (all paramagnetic) in units × 106 were: U(IV), 3690; Np(VI), 2060; Np(V), 4120; Np(IV), 4000; Pu(IV), 1610; Pu(III), 370; Am(III), 720. The results could be interpreted only on the basis of electronic configurations 5fn, even though susceptibilities were generally lower than the theoretical values and lower than experimental values for corresponding lanthanide 4fn cations. The lower values should be expected as a result of the Stark effect produced by electric fields of anions and of water dipoles. Failure of the Russell-Saunders approximation to the coupling between electrons may account for some of the error in the theoretical calculations. That the susceptibilities of Pu(III) and Am(III) are manyfold lower than those of Sm(III) and Eu(III), respectively, is attributed to wider multiplet splitting in the actinide atoms.
The Absorption Spectrum and the Dissociation of H2O2
Authors: Edse Rudolph
Published: January 2005

Although Holt, McLane, and Oldenberg state that they were unable to observe a sharp cut in the absorption spectrum of hydrogen peroxide vapor, it is shown that their measurements indicate a rather abrupt increase of the absorption coefficient at 1920A.

It is doubtful that the dissociation energy of hydrogen peroxide can be derived from its absorption spectrum. However, it seems possible that the photo-chemical decomposition of hydrogen peroxide gives an upper limit for its dissociation energy.

Our measurements of the absorption coefficient of hydrogen peroxide agree well with the results of Holt, McLane, and Oldenberg.
The Occurrence of Hypsochromic Shifts on Alkyl Substitution: Structure and Color of Methylated Derivatives of Azulene
Authors: Pullman Bernard , Mayot Marcel , Berthier Gaston
Published: January 2005

While two methylated derivatives of azulene show the usual bathochromic shift with respect to azulene itself, the remaining three isomers show an unusual displacement of the visible spectrum toward shorter wave-lengths. No steric effects can be claimed to account for these last results which are considered as representing genuine hypsochromic shifts brought about by alkyl substitution and due to the particularities of the structure of azulene and its derivatives. It is then shown by molecular orbital method calculations that Mulliken's N→V theory of color accounts satisfactorily for the observed facts. In the methylated derivatives showing a bathochromic shift, the calculated excitation energy of the N→VI transition appears to be smaller than the corresponding energy in azulene itself, while the reverse is true for the compounds exhibiting a hypsochromic shift. The general conditions necessary for the occurence of hypsochromic shifts upon alkylation and a few predictions of such shifts in other hydrocarbons are given.
Some Studies in Molecular Orbital Theory III. Substitution in Aromatic and Heteroaromatic Systems
Authors: Longuet-Higgins H. C.
Published: January 2005

It is shown that LCAO molecular orbital theory, when combined with first-order perturbation theory, provides a very simple procedure for estimating how far electronic effects will modify the transition state energies for substitution reactions in alternant molecules. This procedure is shown to lead to the same qualitative predictions as resonance theory, but has the advantage that it gives at the same time quantitative information as to the relative effects of substitution at different points in a complex system. The theoretical results agree well with experiment as far as can be ascertained at present.

The approximations involved, and their relation to those of resonance theory, are discussed in detail.
Infra-Red and Raman Spectra of Fluorinated Ethylenes. I. 1,1-Difluoroethylene
Authors: Smith D. C. , Nielsen J. Rud , Claassen Howard H.
Published: January 2005

The infra-red absorption of CF2:CH2 gas has been investigated between 2 and 22.7μ with a prism spectrometer of high resolution. The Raman spectrum of the compound in the gaseous state has been photographed with a three-prism glass spectrograph of linear dispersion 15A/mm at 4358A. The 12 fundamental vibration frequencies have been assigned and the observed spectra have been interpreted in detail.
Infra-Red Absorption Spectrum of Dimethyldiacetylene
Authors: Cleveland Forrest F. , Greenlee Kenneth W. , Bell Ely E.
Published: January 2005

The infra-red absorption spectrum of freshly prepared dimethyldiacetylene has been obtained for the vapor existing above the solid or liquid at temperatures of 25°, 40°, 60°, 80°, 85°, and 110°C; for the gas at 130°C; and for CCl4 and cyclohexane solutions. A Beckman IR−2 spectrophotometer with rocksalt optics was used. The observed values of the Ā2 frequencies were 940, 1369, 2157, and 2920, as compared with the calculated values 903, 1368, 2131, and 2946 cm−1 given previously by Meister and Cleveland. A frequency assignment based upon the D3h′ structure is given: One of the 20 distinct fundamental frequencies (10 non-degenerate, 10 doubly degenerate) corresponds to the internal free rotation; the other nine non-degenerate and seven of the doubly degenerate fundamentals are rather certainly assigned and tentative values are given for the remaining three. All of the other observed Raman and infra-red bands could be accounted for as binary combinations, except the 2225-cm−1 Raman line and the 2228-cm−1 infra-red band which seem to originate from the coincidence of a large number−43 and 40, respectively—of ternary combination frequencies. The sample used melted at 64.95±0.03°C, corresponding to a purity of 99.77±0.05 mole percent. A description of the method of preparation is given.
On the Non-Orthogonality Problem Connected with the Use of Atomic Wave Functions in the Theory of Molecules and Crystals
Authors: Löwdin Per-Olov
Published: January 2005

The treatment of molecules and crystals by the Heitler-London method or by the collective electron model can be based on the atomic orbitals φμ of the system. These orbitals are in general overlapping, and the corresponding overlap integrals Sμν, given by (1), have almost universally been neglected in the literature as causing undesirable complications. Here we will take these overlap integrals into consideration and show that they, instead of being negligible, are of essential importance in molecules and in crystals. The problem is simply solved by considering the orthonormalized functions [open phi]μ, given by (21), as the real atomic orbitals. The solution is worked out in detail for (I) the molecular orbital method of treating molecules, (II) the Bloch orbital method of treating crystals, and (III) the Heitler-London method of treating both these systems in some simple spin cases. Some numerical applications are given for ionic crystals, showing that the overlap effects are responsible for all the repulsive forces in these solids. It is also shown that the overlapping adds interesting new features to the properties of molecules and crystals, namely the ``many-orbital-effects,'' corresponding to certain ``many-body-forces'' in ionic solids.
Effect of Temperature on the Lifetime of Fluorescence of Solid Acetone
Authors: Kaskan W. E. , Duncan A. B. F.
Published: January 2005

The lifetime of fluorescence of solid acetone was found to be a function of temperature, and of an unknown parameter which was interpreted as the state of aggregation of the sample. Both of these effects were interpreted in terms of the exciton theory, in which a quantum of electronic excitation energy is capable of wandering through the crystal before it is emitted as light.
Appearance Potentials of Some Metastable Transition Ions Found in Hydrocarbon Mass Spectra
Authors: Fox R. E. , Langer Alois
Published: January 2005

The appearance potentials of some metastable transition peaks in normal butane, isobutane, the butenes, and 1,3-butadiene have been studied along with the parent ions in each metastable transition. A comparison shows that in most cases studied, an additional energy of about 2 ev is required for the formation of the metastable state. However, in the case of normal butane, two transitions were studied in which no additional energy was required within an experimental error of 0.3 ev. Evidence is presented which indicates that in some cases the appearance potentials of ions in hydrocarbon spectra are affected by these metastable ion contributions. This effect may account for some of the unexplained discrepancies found in published data on hydrocarbon gases. Check values of some ions in methane, ethane, and propane were taken to determine the performance of the instrument. A comparison of these results is made with previously published data.
The Ratio of the Specific Heats of Gases, Cp/Cv, by a Method of Self-Sustained Oscillations
Authors: Koehler W. F.
Published: January 2005

The ratio cp/cv at room temperature has been determined for He, A, H2, N2, O2, CO2, N2O, SO2, CH4, and C2H4 by a method of self-sustained oscillations. The results are reproducible to within 0.1 percent and agree with the best values reported by other observers to within 0.1 percent. The method requires the measurement of a temperature, a pressure and a period of oscillation. The theory of the self-sustained oscillations has been developed to include the effects of the mass of the oscillating gas, damping, heat conduction, and the departure of the behavior of actual gases from the ideal gas law.
Elastic Scattering and Neutralization of Low Velocity Hydrogen Ions in Normal Butane and Isobutane
Authors: Simons J. H. , Cramer W. H.
Published: January 2005

The low velocity scattering of H+, H2+, and H3+ in both normal and isobutane has been measured at ion velocities of less than 150 volts. Ion neutralization was detected and measured for all three ions in both hydrocarbons. The potential functions between the ion and molecule as evaluated from the elastic scattering have been obtained for all three ions in both hydrocarbons. For H+ these functions in both hydrocarbons have the same form with the same values of the exponent over the same range of distance. The force constant, however, is considerably greater for the branch chain compound. For certain ranges of distances the potential functions of the three different ions in both of the hydrocarbons show values of the exponent less than 4. For substances possessing no permanent dipole similar results have previously been obtained only in those cases where there is a potentiality of chemical combination.
Dissociation and Exchange Equilibria of the Tritium Halides
Authors: Bigeleisen Jacob
Published: January 2005

The ratios of the partition functions of the tritium halides to their respective protium halides have been calculated. These are combined with one another to give the exchange equilibria between the six pairs of tritium and protium halides. The exchange equilibria with water are calculated. From the exchange equilibria between the tritium halides and protium and the free energy of dissociation of the protium halides, the dissociation equilibria of the tritium halides have been calculated.

The experimental data on the dissociation of HI are reviewed and it is shown that the data of Taylor and Crist on DI and HI are self-consistent as well as in good agreement with theory. The heat of formation of HI at absolute zero, ΔH00, is found to be − 1007±10 calories per mole.
Migration of Sodium Ions through Quartz Plates in an Electric Field. I
Authors: Vogel Richard C. , Gibson George
Published: January 2005

The kinetics of the migration of sodium ions through crystalline quartz plates has been studied. This migration, which was induced by an electric field, is assumed to take place through tunnels inherent in the crystal structure and parallel to the principal axis of the quartz. It was shown that the only important mechanism of current flow is the migration of sodium ions through the quartz plate. The activation energy is from 22 to 25 kcal. and depends upon the potential gradient. The rate of migration of the sodium ions is essentially independent of the concentration of the sodium ions.
On the Photographic Reciprocity Law Failure and Related Effects. II. The Low Intensity Sequence Effect
Authors: Katz E.
Published: January 2005

A quantitative theory of all details of the low intensity sequence effect is given on the basis of the following assumptions. A monatomic Ag speck is unstable against thermal agitation, a diatomic speck is stable, but for development a speck of more than two atoms is required. The theory is based on that for low intensity failure as developed in paper I.
The Raman Spectrum of Hexachlorodisilane
Authors: Katayama Mikio , Simanouti Takehiko , Morino Yonezo , Mizushima San-ichiro
Published: January 2005

The Raman spectrum of hexachlorodisilane was observed in the liquid state and the normal vibrations of this molecule were calculated by use of the Urey-Bradley field. The seven observed Raman frequencies could be assigned to the fundamental vibrations and the molecule was found to belong to the D3h′ symmetry. This means that the molecule exerts internal free rotation around the Si–Si bond as axis. This is in conformity with the experimental result of the electron diffraction investigation.
Hexacovalent Bond Orbitals III
Authors: Duffey George H.
Published: January 2005

A set of six equivalent orthogonal bond orbitals of trigonal antiprism symmetry are considered. The orbitals are of type snp3d3−n. The strongest orbitals are obtained when n equals 0.8427. These orbitals are only slightly stronger than the octahedral orbitals. The trigonal antiprism orbitals are stronger than the corresponding trigonal prism orbitals. The SF6, [Complex chemical formula], and Fe(CN)6≡ structures are discussed. The relation used for estimating energies is used to estimate bond energies of CH bonds in the structures [Complex chemical formula], and ≡C–H.
The Catalysis of the Ortho-Para Conversion in Liquid Hydrogen
Authors: Swenson C. A.
Published: January 2005

The catalysis of the ortho-para conversion in liquid hydrogen is of importance for the quantity production of pure parahydrogen. Parahydrogen is of interest in itself: however, from a purely practical standpoint, if liquid hydrogen were to be kept for any considerable length of time, it would be much more economical to store liquid parahydrogen than normal (25 percent para) liquid hydrogen. Rough determinations of the conversion constant, both in the adsorbed layer of the catalyst and in the actual liquid, are given for activated charcoal and for silica gel onto which oxygen gas had been adsorbed. The heat of mixing of ortho- and parahydrogen was also measured, and found to be smaller than the accuracy of measurement.
The Magnetic Susceptibility of Bromine-Graphite
Authors: Goldsmith M.
Published: January 2005

The magnetic susceptibilities of graphite and bromine-graphite have been measured. Possible structures of bromine-graphite are discussed.