bluuebunny/crossref_metadata_2025 huggingface dataset:
Second-Order Transitions and Critical Phenomena
Authors: Scott Robert L.
Published: January 2005

Second-order transitions occur when a system which is completely ordered at low temperatures (degree of order s=1) changes gradually to a disordered state, ultimately reaching s=0 at the critical or Curie temperature Tc. Elementary theories always predict that s2 ∝ (1 − T/Tc) and predict limiting heat capacities at Tc which are finite and much smaller than those observed. Experimental data on liquid-liquid and liquid-vapor critical phenomena fit a relation in which the cube of s, not the square, is proportional to 1 − T/Tc. A crude argument, using this empirical equation, leads to the conclusion that the heat capacity rises sharply, probably reaching infinity at the Curie temperature. Experimental data on ammonium chloride and on quartz fit a relation in which the anomalous heat capacity is proportional to an inverse power of (1 − T/Tc).
The Representation of Gas Properties in Terms of Molecular Clusters
Authors: Woolley Harold W.
Published: January 2005

The equation of state of a gas in virial form is derived from the equilibrium constants for the formation of molecular clusters. It is indicated that by choosing effective Lennard-Jones parameters independently for clusters of various numbers of molecules, the actual virial coefficients may be represented more satisfactorily. Results for the third virial coefficient are shown for A, N2, CO, CO2, CH4, C2H4, CF4, and Xe.
Substituted Methanes. X. Infrared Spectral Data, Assignments, Potential Constants, and Calculated Thermodynamic Properties for CF3Br and CF3I
Authors: McGee Paul R. , Cleveland Forrest F. , Meister Arnold G. , Decker Charlotte E. , Miller Sidney I.
Published: January 2005

Infrared wave numbers, relative intensities, and percent transmission curves have been obtained for CF3Br and CF3I in the region 400–2200 cm−1. Assignments are given for the observed bands, in which the assignments of Plyler and Acquista for ν2 and ν3 are interchanged. Potential constants were calculated for both molecules by the Wilson FG matrix method. And, finally, the heat content, free energy, entropy, and heat capacity for the ideal gaseous state at 1 atmos pressure were calculated for 12 temperatures from 100°to 1000°K, using a rigid rotator, harmonic oscillator approximation.
Quasi-Chemical Treatment of Mixtures of Oriented Molecules
Authors: Tompa H.
Published: January 2005

A simple model of a solution is constructed, assuming that the interaction energies of the molecules depend on their mutual orientation. The thermodynamic properties of the model are calculated by the combinatory method of the strictly regular solution. Graphs of the excess free energy, entropy, and heat of mixing are obtained numerically for a number of typical cases.
A Quantum-Mechanical Treatment of Virial Coefficients
Authors: Kilpatrick John E.
Published: January 2005

The virial equation of state for gases has been developed with the quantum-mechanical grand partition function as a basis, instead of with the usual Slater sum or the density matrix. Attention is thereby focused on the energy levels of systems of one, two, three, etc., molecules rather than on their wave functions. An explicit, closed solution has been found for the nth virial coefficient in terms of the first n cluster integrals which is valid either classically or quantum mechanically. A simple generating function for the virial coefficients has been proposed.
The Far Ultraviolet Absorption Spectra of Simple Alkyl Amines
Authors: Tannenbaum Eileen , Coffin Esther M. , Harrison Anna J.
Published: January 2005

A quantitative study of the absorption spectra of ammonia, the three methyl and the three ethyl amines, has been made in the region 39 000 to 63 000 cm−1. Three electronic transitions have been observed in most cases. The first is of low intensity particularly in the secondary amines, the second is of higher intensity and increases from the primary to the tertiary compound, and the third, which is only partially covered by these measurements, is of intermediate intensity. The positions of all transitions, particularly the second, are influenced by alkyl substitution. These transitions are discussed in relation to the spectrum of ammonia. Vibrational structure, present in ethyl amine, methyl amine, and dimethyl amine, has been analyzed in part.
F Bands in Some Mixed Crystals of the Alkali Halides
Authors: Gnaedinger Robert J.
Published: January 2005

X-ray induced F bands in melt-grown mixed crystals of KCl and RbCl were studied. Though no resolution of ``component'' F bands was obtained at liquid nitrogen temperature, the behavior of the F band parameters as a function of concentration of RbCl in KCl and as a function of temperature is shown to be explainable by postulating the existence of a set of ``component'' F bands, each arising from an F center with a given composition of positive ions immediately surrounding it. Some studies of other mixed crystals are also mentioned.
An Infrared Spectroscopic Study of the Carbonyl Stretching Frequency in a Group of Ortho and Para Quinones
Authors: Josien Marie-Louise , Fuson Nelson , Lebas Jeanne-Marie , Gregory Thomas M.
Published: January 2005

This paper reports on an experimental study of the C=O stretching vibration frequency in a large number of quinonoid compounds, both substituted and unsubstituted. For nonsubstituted ortho and para quinones, relationships between the carbonyl frequency and (a) the number of fused rings, (b) the oxidation-reduction potential, and (c) the index of free valence on the parent hydrocarbon are pointed out and discussed. It is shown that for a six-atom quinonoid ring the C=O frequency is, to a first approximation, a function of the C=O bond order. For substituted quinones, the variation in the carbonyl frequency is related to the induction effect of the substituent in the same way as is the variation in oxidation-reduction potential. Certain hydroxy-substituted quinones show spectral anomalies which do not seem to fit into the usual category of hydrogen bonded compounds.
The Microwave Spectrum of C8H13Br and C8H13Cl
Authors: Nethercot A. H. , Javan A.
Published: January 2005

The spectrum and structure of the molecules C8H13Br and C8H13Cl have been determined. Despite the large size of these molecules, the spectra can be analyzed with the exception of the quadrupole hyperfine splittings which cannot be resolved. The B values are 1090.9 Mc for Cl35, 1065.9 for Cl37, 725.9 for Br79, and 718.5 for Br81. The value of the normal single bond carbon-carbon distance is found to be dc—c=1.545±0.004A. The angle of twist about the symmetry axis is φ=0°±4°, and the angle between the carbon-carbon and carbon-halide bonds is θ=109°50′±10′.
Theoretical Considerations Concerning Hammett's Equation. IV. Calculation of ρ-Values
Authors: Jaffé H. H.
Published: January 2005

The assumption is made that the effect of a meta or para substituent X on the reactivity of a reacting center Y in a compound [Complex chemical formula] depends only on the electron density change induced by the substituent in the atom at which Y is attached to R. Using this assumption relative values of Hammett's reaction constant (ρ) are calculated for a given reaction in several series of compounds having the above formula. The calculations require the computation of the electron density changes induced by substituents in the atom at which Y is attached to R. The computations are carried out by the semiempirical LCAO MO method for several cases where R and the benzene ring form part of a single conjugated system. The resulting relative ρ-values are compared with experimental data. Reasonable agreement is found.
High Temperature Susceptibility of Permanent Dipole Lattices
Authors: Rosenberg Robert , Lax Melvin
Published: January 2005

Van Vleck's exact classical treatment of dipolar materials is modified and extended. (For convenience, his expansion of the susceptibility χ in powers of T−1 is replaced by an expansion of the effective molecular polarizability αs.) The present procedure exhibits the dependence of the coefficients of T−p on lattice sums over certain typical interactions within ``clusters'' of dipoles. This feature, together with an extension to the fourth-order term, sheds light on the analytic character as well as numerical accuracy of the spherical approximation. The exact treatment also provides a standard of comparison for all other approximation methods. The fourth-order coefficient is evaluated for a simple cubic arrangement of the dipoles, and for the Onsager liquid model.

The spherical result, at least in the high temperature range, includes the most important types of interactions within clusters; it reproduces the exact series through the third-order term, and differs from the exact simple-cubic fourth-order term by only 5 percent. In addition, when evaluated for the Onsager liquid model, the spherical solution is apparently an improvement over Onsager's solution.
Interatomic Electric Quadrupole-Quadrupole Coupling in Salts of Cerium
Authors: Finkelstein R. , Mencher A.
Published: January 2005

We have calculated the magnetic properties of a cerium salt in terms of the one-atom (crystalline field) model at temperatures greater than 1°K. Because the cerium ion is not in an S state, its electronic charge distribution has a quadrupole moment; we have determined the influence of interatomic electric quadrupole-quadrupole interactions on the magnetic moment and optical rotation at very low temperatures. In cerium ethylsulfate this coupling is antiferromagnetic with a characteristic temperature of τ=0.01〈r2〉4 degrees, where 〈r2〉½ is the rms radius of the 4f orbit in A. This interaction may be at least partly responsible for a low temperature anomaly found by Becquerel, de Haas, and van den Handel, as well as for the sharp increase in specific heat noticed during adiabatic demagnetization. In other salts τ may be of opposite sign (ferromagnetic case) and possibly much larger (∼1°K).
On the Molecular-Orbital Theory of Conjugated Organic Compounds with Application to the Perturbed Benzene Ring
Authors: Löwdin Per-Olov
Published: January 2005

The electronic structure of a molecular system is investigated by using the idea of molecular orbitals. The behavior of the separate molecular orbitals and the orbital energies under the influence of the substitution of one or more heteroatoms, considered as perturbations, is examined. A series of quantities, separate charge orders, bond orders, and mutabilities are introduced, giving information about some characteristic physical and chemical properties of the compound. The perturbation scheme is carried out explicitly to the second order in the energies and to the first order in the orbitals, and special attention is paid to the treatment of degenerate levels. The overlapping problem is fully discussed. The basic results are independent of any empirical parameters, and they may be used either in the naïve semi-empirical theory or in a more elaborate theoretical approach based on an antisymmetrized molecular wave function.

As an example, numerical applications are carried out in detail on benzene. Separate charge orders, bond orders, and mutabilities are tabulated, and orbital energies for a perturbed benzene ring with one or two heteroatoms are explicitly given.
The Absorption Spectrum of Cyclopropane in the Vacuum Ultraviolet. Note on the Absorption Spectrum of Methyl Cyclopropane
Authors: Wagner Paul , Duncan A. B. F.
Published: January 2005

The spectrum of cyclopropane has been investigated from 600A to 2200A with high dispersion. Three very broad electronic transitions with apparent maxima at 1594, 1449, and 1202A were found. A strong continuous absorption begins at 1123A, and no resolved transitions could be observed at shorter wavelengths. A very weak band system consisting of twelve bands was found between 1889 and 1816A. It is concluded that the electronic transitions arise from excitation of an electron from a bonding molecular orbital localized principally in the carbon ring. The weak transition is interpreted as a forbidden transition. A tentative analysis of the bands in this transition is given. A note on the absorption spectrum of methyl cyclopropane is included.
Some Heavy Water Rotational Absorption Lines
Authors: Jen C. K. , Bianco D. R. , Massey J. T.
Published: January 2005

Three new heavy water rotational absorption lines have been observed in the microwave region. One of these lines and another line previously observed by McAfee have been identified as HDO lines by a study of the variation of their intensities with isotopic molecular concentration. By interpreting their Stark structure, the two HDO lines are assigned as follows: HDO:8−1→80 at 24 884.85 Mc/sec and HDO:6−2→7−6 at 26 880.47 Mc/sec. In addition, results on the Zeeman spectra of the two identified HDO lines are presented.
The Thermal Decomposition of Nitromethane
Authors: Hillenbrand Louis J. , Kilpatrick Mary L.
Published: January 2005

A study of the thermal decomposition of nitromethane was made by the flow method, with nitrogen as carrier gas, the reaction being followed by polarographic analysis of the effluent from the furnace for nitromethane. When carefully dried nitrogen was used the rate of disappearance of nitromethane became erratic; it was, however, found possible to obtain reproducible results by passing wet nitrogen through the unit before the kinetic run. The decomposition follows the first-order law, and over the range 420–480°C is represented by the equation k=2.7×1013 exp(−50 000/RT) sec−1. At 420°, k is in good agreement with the value obtained by Cottrell, Graham, and Reid by the static method, but at higher temperatures the observed rate is lower than that computed from their equation. Although the energy of activation is close to that required to break the C–N bond, the high initial yield of formaldehyde obtained in the flow-method experiments suggests that the rate is in part determined by an intramolecular rearrangement.
Infrared Spectra and Structure of Uranyl and Transuranium (V) and (VI) Ions in Aqueous Perchloric Acid Solution
Authors: Jones Llewellyn H. , Penneman Robert A.
Published: January 2005

Infrared spectra of aqueous solutions of U(VI), Np(VI), Pu(VI), and Am(VI) show conclusively that these ions exist as symmetrical and linear, or nearly linear, XO2++. The spectra of Np(V) and Am(V) show that they are probably XO2+ ions. Force constants and estimated distances are given for the X—O bonds. For the XO2++ series, the X—O force constant is expressed as a parabolic function of atomic number, with the maximum occurring at NpO2++. This is contrary to behavior expected if there were a regular contraction in ionic radii for the series XO2++.
Polarized Fluorescence of Molecules of Some Single Organic Crystals
Authors: Ganguly S. C. , Choudhury N. K.
Published: January 2005

The polarized fluorescence of single crystals of pyrene, phenanthrene, and benzil have been studied. It has been observed that, whether the incident light is polarized or not, the fluorescent light is polarized in all three cases. From the study of the intensity of fluorescence light the directions of oscillators, and so the favored condition of excitation of fluorescence with particular reference to the crystal structure, have been determined, and an attempt has been made to find the orientation of the molecules with reference to the crystal axis where the structure is not known.
The Effect of Pressure on Diffusion in CS2 Organic Mixtures
Authors: Koeller R. C. , Drickamer H. G.
Published: January 2005

Diffusion coefficients are presented as a function of pressure to 10 000 atmospheres for the following systems: 50 mol percent n−heptane−50 percent CS2 0∘−20∘−40∘;50 mol percent 2,4 dimethylpentane−50 percent CS2 20∘−40∘;50 mol percent toluene−50 percent CS2 20∘−40∘;50 mol percent methylcyclohexane−50 percent CS2 0∘−20∘−40∘;50 mol percent n−octane−50 percent CS2 20∘C;50 percent chlorobenzene−50 percent CS2 20∘−40∘;80 percent chlorobenzene−20 percent CS2 40∘;50 percent n−butanol−50 percent CS2 20∘−40∘;50 percent iso−butanol−50 percent CS2 20∘−40∘;using S35 tagged CS2.

The results are interpreted in terms of the activation volume, enthalpy, and entropy, and conclusions are drawn concerning the effect of pressure on the structure of the liquids.
The Structures of the Interhalogen Compounds. I. Chlorine Trifluoride at −120°C
Authors: Burbank Robinson D. , Bensey Frank N.
Published: January 2005

A technique has been developed for handling the extremely reactive interhalogen compounds which makes it possible to investigate their structures by x-ray diffraction at low temperatures. As the first step in a program of study of the interhalogen group the crystal structure of chlorine trifluoride has been determined at −120°C. The chlorine trifluoride molecule is planar with the point group symmetry mm. The Cl atom is bonded to one F atom at 1.621A and to two F atoms at 1.716A. The F–Cl–F bond angle is 86°59′. In the succeeding pages of this journal, a parallel investigation of the vapor phase by microwave spectroscopy is presented by Dr. D. F. Smith. The molecular configuration is identical in the two cases.
The Accommodation Coefficient Technique Applied to a Study of Molecular Oxygen Film on Tungsten
Authors: Morrison John L. , Grummitt W. E.
Published: January 2005

The accommodation coefficient method of Roberts was used to measure the adsorption isotherms of the upper molecular oxygen film on tungsten at 25 and 100°C and at pressures from 9×10−9 to 1×10−4 mm Hg. The isotherms were found to fit Wang's theoretical isotherm for a mobile film with repulsive interaction. An entropy of adsorption was calculated from the surface pressure by Hill's method and found to be about four entropy units at low film concentrations. The large discrepancy between calculated and theoretical entropies suggests either or both irreversible effects and nonlinearity of the relation between accommodation coefficients and surface coverage. The minima which are exhibited during the growth with time of the adsorbed film at 100°C may be direct evidence for the presence of holes in the immobile first layer which are filled by activated diffusion from the upper layer.
The Potential Function of Ethylene
Authors: Crawford Bryce L. , Lancaster John E. , Inskeep Richard G.
Published: January 2005

The infrared spectrum of a-C2H2D2 has been obtained, and the vibrational frequencies used to complete the calculation of the force constants of C2H4. The spectra of C2H3D, trans-C2H2D2, and a mixture of cis- and trans-C2H2D2 were also observed and used to check the force-constant calculations.
Diffusion with a Sharp Moving Boundary
Authors: Fujita Hiroshi
Published: January 2005

When the molecules of a diffusing substance react with the medium into which they diffuse in such a manner that they no longer take part in the diffusion process, a sharp boundary line results which is displaced at a rate determined by the conditions of the particular experiment. A theory of this phenomenon was presented by J. J. Hermans and was applied to determine the diffusion constants in some ion-gel systems. In the present paper the method of moments which was recently worked out by Yamada to deal with the boundary-layer equations is applied to obtain approximate solutions of the basic equations of the J. J. Hermans theory for both linear and cylindrical diffusions. The particular concern of the present paper is to analyze the experimental data obtained by J. J. Hermans for cylindrical diffusion in a copper ion-cellulose xanthate system on a more reliable basis than in J. J. Hermans' paper referred to. It is found that the present analysis provides the diffusion constants which are considerably higher (about 2.6 times) than those evaluated by J. J. Hermans. Nevertheless, the values found are still too low as compared with the experimental value determined by the steady-state method, and a further research of the problem needs to be made.
The Possible Microwave Absorption in the Molecules belonging to the Point Groups D2d ≡ Vd and Td
Authors: Mizushima Masataka , Venkateswarlu Putcha
Published: January 2005

It is shown that pure rotational absorption in the molecules belonging to the point group D2d ≡ Vd is possible if the molecule is in the excited, preferably lowest, doubly degenerate vibrational state. The approximate positions of these microwave absorption lines, as calculated from the B value obtained from the infrared data, are given in the case of allene. It is also shown that the pure rotational absorption is possible in the molecules belonging to the point group Td if they are in the excited triply degenerate (F2) vibrational states. The matrix element of dipole moment corresponding to our transition is about the same as that of the overtone vibrational bands, in both cases.
Adsorption Studies on Clay Minerals. II. A Formulation of the Thermodynamics of Exchange Adsorption
Authors: Gaines George L. , Thomas Henry C.
Published: January 2005

Expressions for thermodynamic equilibrium constants are set up for the ion-exchange equilibria of models defined in terms of operational variables. Formulas summarizing the methods for the computation of the requisite activity coefficients are given. In particular, the effects of the solvent, which is considered as an independently variable component, are taken explicitly into account.
A Spectrometer for the Far Infrared and the Spectrum of 1,2 Dichloroethane
Authors: Bohn C. R. , Freeman N. K. , Gwinn William D. , Hollenberg J. L. , Pitzer Kenneth S.
Published: January 2005

A brief description is given of a grating spectrometer which has been used in the wavelength range 22 to 77 microns. Test measurements of the pure rotation spectrum of water vapor gave excellent agreement with other investigators. The spectrum of 1,2 dichloroethane shows bands at 409, approximately 265, and 222 cm−1. A band with its center a little less than 135 cm−1 also is indicated. The value 223 cm−1 suggested for the antisymmetric skeletal deformation frequency of the trans form of dichloroethane by Mizushima, Morino, and Simanouti is thus confirmed. Their suggestion was based on a very weak Raman band which they attributed to this infrared active frequency on the basis of a breakdown of selection rules in the liquid. Our result also confirms various statistical-thermodynamic calculations for this substance.
On the Electrical Conductivity of Some Alkaline Earth Titanates
Authors: Weise E. K. , Lesk I. A.
Published: January 2005

The compounds Mg2TiO4, MgTiO3, MgTi2O5, CaTiO3, SrTiO3, and BaTiO3 were prepared in crystalline form by reactions in the solid state. The rod-shaped samples were sintered in oxygen at 1450°C and reduced in hydrogen at temperatures from 560°C to 1400°C producing n type semiconductors. Resistivity values from 10−1 to 108Ω·cm at 25°C were obtained. Reductions of about 3 percent by weight could be given the most reduced magnesium titanates while the largest reduction obtainable in CaTiO3, SrTiO3, or BaTiO3 was less than 0.25 percent.

The logarithm of resistivity was plotted versus reciprocal absolute temperature and showed a linear dependence in most cases over a wide range of temperature and resistivity. The curves for BaTiO3 changed the slope abruptly at approximately 115°C, probably attributable to the crystal structure change at the Curie temperature, about 120°C.

The dependences of impurity activation energy and Fermi level on percent reduction were determined for the case of Mg2TiO4. The Biltz-Meyer rule, stating a linear relationship of impurity activation energy with resistivity at a reference temperature, was not obeyed over the large range of reductions obtained.
Intermolecular Force Constants from Thermal Diffusion and Other Properties of Gases
Authors: Srivastava B. N. , Madan M. P.
Published: January 2005

The thermal diffusion data on argon have been examined on the basis of the Lennard-Jones 12:6 model by reducing the experimental data through a more appropriate variation of RT with temperature than has been done hitherto. The value of the force constant ε, thus determined from the observed variation of RT with temperature, is found to increase slightly with temperature. This variation of ε shows the inadequacy of the model in the entire range of temperatures but gives a good idea of its effective range of usefulness. These values of ε have been utilized to give r0 from the viscosity and self-diffusion data. From these the force constants μ and λ have also been evaluated and are likewise found to vary with temperature. These variations of ε, r0, μ, and λ have been explained theoretically and are shown to be in accord with experimental data on the second virial coefficients of argon. The force constants for O2, N2, CH4, and CO have also been similarly determined and are found to agree with other determinations.
The Ultrasonic Velocity, Density, and Compressibility of Supercooled H2O and D2O
Authors: Lagemann R. T. , Gilley L. W. , McLeroy E. G.
Published: January 2005

The velocity of compressional waves in liquid water (H2O and D2O) has been measured over a range of temperature extending to some six degrees below the nominal freezing point, using a fixed-frequency variable-path sonic interferometer. The density of heavy water in the supercooled state has been determined and values of the adiabatic compressibility calculated. The curves representing the variation of density with temperature are symmetrical and congruent for the two isotopic liquids. It is confirmed that the compressibility of D2O is greater than that for ordinary water. The new measurements of the three properties yield values which fall on smooth extrapolations of the previously known data, indicating that there is no partial ordering of the liquid structure into the solid structure at temperatures below the nominal freezing point, at least none at times removed from the start of observed freezing.
Electronic Conduction in Silicon Carbide
Authors: Kendall J. T.
Published: January 2005

Pure silicon carbide was prepared by decomposition of the vapors of silicon tetrachloride and toluene on a hot carbon filament. Various n- and p-type impurity atoms were introduced by the addition of volatile metallic chlorides during the preparation. For the pure substance either n- or p-type crystals could be obtained by varying the ratio of the reaction constituents. The results show that semiconductivity in silicon carbide may be due either to nonstoichiometric proportions of silicon and carbon, or to the presence of impurity atoms, or (as probably occurs in the commercial product) to both circumstances simultaneously.

A theoretical model for electronic conduction in silicon carbide is proposed, which satisfactorily explains the magnitude of the low and high temperature activation energies observed, their different ratios in n- and p-type crystals, the occurrence of conduction at one of the disturbance energy levels, and the anomalous low Hall constant at low temperatures found in black but not in green silicon carbide. The model may be applicable to other semiconductors in which disturbance centers can give rise to electrons in unlocalized excited states.
The Microwave Spectrum of Arsenic Trifluoride
Authors: Kisliuk P. , Geschwind S.
Published: January 2005

The microwave spectrum of AsF3 is re-examined under high resolution permitting the evaluation of small interactions due to centrifugal distortion and I·J effects, as well as a more precise determination of the rotational constant and quadrupole interaction. The constants determined are: B = 5878.971±0.002 Mc, (eqQ)As = −236.23±0.05 Mc, DJK = −9.±2. kc, a = −6.±7. kc, b = 6.±2. kc, α2 = −5.±1. Mc, and α4 = −0.16±0.04 Mc. In addition, the bond angle is estimated from the quadrupole interaction by means of a comparison with AsCl3, yielding ∠F–As–F = 102°±2°.
Collisional Excitation of F2O
Authors: Aroeste Henry
Published: January 2005

The quantum mechanics is applied to the calculation of the intrinsic probability of excitation of vibration and rotation of an idealized F2O molecule by a neon atom. Comparisons are made of the excitation of the three normal vibrations from the zeroth to the first states. The probabilities of excitation of rotation accompanying vibrational excitation are explicitly shown and discussed. Further, excitations involving a change of two and four vibrational quantum numbers are approximated.
A Calorimetric Calibration of Gamma-Ray Actinometers
Authors: Hochanadel C. J. , Ghormley J. A.
Published: January 2005

The yield for gamma-ray oxidation of ferrous sulfate in air saturated 0.4M sulfuric acid was found to be 15.6±0.3 ferrous ions oxidized per 100 electron volts absorbed. This value was based on calorimetric measurements of cobalt gamma-ray energy absorption in water at intensities of 25 r/sec, 74 r/sec, and 225 r/sec. The yield for reduction of ceric sulfate in air saturated 0.4M sulfuric acid solution, determined by comparison with the ferrous sulfate yield was 2.52±0.05 ceric ions reduced per 100 ev absorbed. The effects of several variables on these yields were investigated.
Normal Coordinate Analysis of the Nonplanar Vibrations of 1,3,5-Trifluorobenzene
Authors: Ferguson Eldon
Published: January 2005

A normal coordinate analysis has been carried out of the nonplanar vibrations of 1,3,5-trifluorobenzene based on the frequency assignments of Nielsen, Liang, and Smith and utilizing results from Miller and Crawford's normal coordinate treatment of the nonplanar vibrations of benzene. The analysis has furnished strong support for Nielsen, Liang, and Smith's tentative assignment of the lowest A2″ fundamental and has led to the conclusion that their value for the highest E″ fundamental is too high. The spectral data have been re-examined, and a reasonable new assignment has been given for this E″ fundamental. A plausible reinterpretation consistent with the change in assignment of the E″ fundamental has been given of several of the combination and overtone bands.
The United Atom Treatment of H2+
Authors: Matsen F. A.
Published: January 2005

Using first-order perturbation theory on the united atom, closed expressions are obtained for the energies, and the charges which minimize those energies, of the following states: 1sσ, 2pσ, 2pπ, 3pπ, and 3dδ. Numerical calculations based on these expressions show, for the higher states, quite good agreement with the more exact calculations of Teller and Chakravarty.
Simplified Relation Between Thermodynamics and Molecular Distribution Functions for a Mixture
Authors: Zimm Bruno H.
Published: January 2005

An equation is presented connecting the chemical potential, the compressibility, and one of the molecular pair distribution function integrals of a binary mixture.
The Nonadditivity of the Repulsive Potential of Helium
Authors: Rosen Philip
Published: January 2005

The repulsive energy of three helium atoms is calculated using the valence bond method. A great reduction of the required number of exchange integrals is found to be possible using group theoretical arguments. It is found that the effect of nonadditivity is negligible for the internuclear distances involved in most physical problems.
Unified Orbital Theory of the Excited States of the Fluorine Molecule
Authors: Mueller Charles R.
Published: January 2005

The unification of the atomic orbital and molecular orbital theories of the excited states of diatomic molecules is achieved by means of semi-localized orbitals. In particular the classification of the states of the fluorine molecule arising from the interaction of two fluorine atoms in their ground state is discussed.

Quantitative calculations are made for the 1Σg+ and 3Σu+ states and a comparison of the singlet-triplet separation energies and binding energies from the three methods is made. Both two electron and eighteen electron calculations are made. The better molecular orbital calculations give a lower triplet than a singlet state. In the eighteen electron calculation the atomic and semi-localized orbital methods coincide, and the 1Σg+ state is found to be the ground state.
The Photochemical Decomposition of Azomethane
Authors: Jones M. H. , Steacie E. W. R.
Published: January 2005

The photolysis of azomethane has been investigated over the temperature range 24–190°C. The variation in the rates of production of nitrogen, methane, and ethane with absorbed intensity, azomethane concentration, and temperature may be accounted for quantitatively by the reactions CH3N=NCH3+hν→N2+2CH3CH3+CH3N=NCH3→CH4+CH2N=NCH3CH3+CH3→C2H6.

The quantum yield of nitrogen formation was found to be unity and independent of temperature. For the activation energy difference E2—½E3 a value of 7.6 kcal/mole was obtained. Evidence is cited for an association reaction between methyl radicals and azomethane. On the basis of an assumed mechanism, the activation energy of this process is 6.4 kcal/mole.
Absorption Coefficients of Oxygen in the Vacuum Ultraviolet
Authors: Watanabe K. , Inn Edward C. Y. , Zelikoff Murray
Published: January 2005

Absorption coefficients of oxygen were measured at several hundred wavelengths in the region 1050–1900A with a one-meter vacuum monochromator and a phosphor-coated photomultiplier as detector. The absorption intensity of the Schumann-Runge continuum was found to be somewhat less than previous results, and the intensity distribution was less symmetrical. The 19–0 and 20–0 bands of the Schumann-Runge progression were observed and the dissociation limit of the B3Σu− state was 57140±60 cm−1. Several other bands and continua were found at shorter wavelengths.
Dielectric Polarization in Polar Substances
Authors: Harris Frank E. , Alder Berni J.
Published: January 2005

A statistical mechanical theory of the static dielectric constant of polar substances is presented which differs from the previous theories of Kirkwood and Fröhlich in that a precise evaluation of the distortion polarization term is made. The theory is applied to the dielectric constant of ordinary and heavy water and yields 2 percent agreement with experiment over the entire temperature range. Furthermore, the difference between the dielectric constant of water measured at visible and microwave frequencies can be ascribed to vibrations, such as the bending of the O–H–O bond. The calculated dielectric constant of ice agrees with experimental values within a mean deviation of 3 percent over a considerable temperature range using an approximate evaluation of the Pauling model for that substance. Various other liquids are also compared with experiment.
Diffuse Double Layer Theory for Electrolytes of Unsymmetrical Valence Types
Authors: Grahame David C.
Published: January 2005

Equations are derived for the variation of potential with distance and for the components of charge and capacity in the diffuse double layer at a plane interface for electrolytes of the 1:2 and 2:1 valence types. Some additional relations are also deduced for other valence types.
Infrared and Raman Spectra of Fluorinated Ethanes. VI. The Series CF3CH3, CF3CH2Cl, CF3CHCl2, and CF3CCl3
Authors: Nielsen J. Rud , Liang C. Y. , Smith D. C.
Published: January 2005

The infrared spectra of gaseous CF3CH2Cl and CF3CHCl2 have been obtained in the range from 2 to 38μ, and the spectra of the liquids in the range from 2 to 22μ, with the aid of LiF, NaCl, KBr, and KRS−5 prisms. The Raman spectra of these compounds in the liquid state have been photographed with a three-prism glass spectrograph of linear dispersion 15A/mm at 4358A. Depolarization ratios were determined for most of the Raman bands.

All fundamental vibrational frequencies have been assigned; the spectra have been interpreted in detail, and thermodynamic functions have been calculated.
The Infrared Spectrum of Fluoroform from 2.2 to 20μ
Authors: Rix H. D.
Published: January 2005

The absorption spectrum of fluoroform has been investigated with a Perkin-Elmer double-pass spectrometer from 2.2 to 20μ. The resolution is sufficient to make possible an unequivocal assignment of all six fundamentals on the basis of the observed band envelopes. An anomaly is found in the symmetrical C–F stretching vibration; on the evidence now available this vibration should be assigned to the parallel band at 1209.3 cm−1 in the infrared (vapor) and to the polarized Raman line (liquid) at 1117 cm−1. Overtone and combination bands measured include the A1 and E components of the second harmonic of each of the three degenerate fundamentals. The separation of the maxima of the P and R branches of the parallel bands is discussed in relation to the theory of Gerhard and Dennison.
Theory of Radiation Chemistry. II. Track Effects in Radiolysis of Water
Authors: Samuel Aryeh H. , Magee John L.
Published: January 2005

A model is presented which describes the geometrical effects in the radiolysis of water as a result of the diffusion of free radicals. The motion of secondary electrons immediately following the passage of the ionizing particle is discussed in an appendix, and it is concluded that radicals are most likely formed in pairs at the approximate sites of the original ionizations. Models for the diffusion of these radicals are shown to result in a definite fraction of radicals which undergo initial recombination for gamma- and fast beta-rays, for which the spurs are considered as diffusing independently. For alpha-rays a connected-track model is used. For the intermediate case of tritium beta-rays, a two-stage model is constructed. In each case the comparative yields of the ``forward'' and ``radical'' reactions (GF and GR) are calculated. Subsequent chemical effects in pure water and solutions are also considered briefly.
The Mechanism of Unimolecular Reactions
Authors: Kassel Louis S.
Published: January 2005

The general theory of unimolecular reactions is re-examined to determine what type of information about rate constants for specific activated states may be determined from the experimental reaction rate-pressure curves. It is found that the possibilities in this respect are very limited. Contrary to a recent statement by Johnston, data on decomposition of nitrogen pentoxide in the presence of nitric oxide are adequately fitted by the Kassel theory. Data on decomposition of nitrous oxide, however, cannot be fitted by this theory. Failure of the theory in this case is the result of too small a range of decomposition rate constants for various activated states.
Symmetry Factoring of the Kinetic and Potential Energy Matrices
Authors: Crawford Bryce
Published: January 2005

In computing the kinetic-energy matrix for vibrations of large molecules of useful symmetry, a tedious double matrix multiplication is usually involved. A theorem is presented, replacing this by a shorter calculation, which may be used either to save labor or to check the result.
The Reactions of Methyl Radicals with the Hydrogen Isotopes
Authors: Whittle E. , Steacie E. W. R.
Published: January 2005

The photolysis of acetone has been studied in the temperature range 130–420°C. Measurements have been made of the rates of most of the possible reactions of CH3 and CD3 radicals with hydrogen, deuterium, and deuterium hydride. The following activation energies for the abstraction of a hydrogen or deuterium atom have been found: CH3+acetone, 9.7; CD3+d acetone, 11.6; CH3+D2, 11.8; CD3+H2, 11.1; CH3+HD→CH4, 10.0; CH3+HD→CH3D, 11.3; CD3+HD→CD3H, 10.7; CD3+HD→CD4, 10.7 kcal. The steric factors are all of the order of 10−3. The results are discussed in terms of isotope effects with particular reference to the deuterium hydride reactions.
The Infrared Spectrum of CF3D
Authors: Polo Santiago R. , Wilson M. Kent
Published: January 2005

CF3D was prepared in high purity and its infrared spectrum investigated. The fundamental frequencies are ν1(a1)=2257 cm−1,ν2(a1)=1111 cm−1,ν3(a1)=693 cm−1,ν4(e)=1210 cm−1,ν5(e)= 977 cm−1,ν6(e)=502 cm−1.Thermodynamic functions have been calculated with the usual assumptions.
Free Radicals by Mass Spectrometry. IV. The Rate of Combination of Methyl Radicals
Authors: Ingold K. U. , Lossing F. P.
Published: January 2005

The rate of combination of methyl radicals produced by the thermal decomposition of mercury dimethyl has been studied with a free radical mass spectrometer over a large range of temperature (161° to 814°C) and at one temperature (735°C) over a range of total pressure from 4.8 mm to 18.5 mm. The combination was found to be complex, consisting of a second-order homogeneous reaction and a first-order, presumably heterogeneous reaction. Only the second-order reaction was studied in any detail. The rate constant or collision efficiency of this reaction was found to increase with decreasing temperature but showed no dependence on the carrier gas pressure. A negative temperature coefficient was found for the combination which, if expressed as an activation energy, was −2.2±0.5 kcal. It seems, however, more reasonable to regard this effect as a change in the effective collision diameter of the methyl radicals with temperature, the change being due to the van der Waals energy of attraction between the radicals.
The Specific Heat of Crystalline Selenium at Low Temperatures
Authors: Desorbo Warren
Published: January 2005

Studies on the low temperature specific heat of crystalline selenium have been extended down to 15°K. The data are compared with a calculation based on a one-dimensional-continuum model with which good agreement is shown to exist down to about 37°K. Below this temperature, deviations are described in terms of an anisotropic continuum which considers the ``interaction'' between atom chains.

The values of the thermodynamic functions, entropy, enthalpy, and free energy have been evaluated and tabulated at regular integral values of temperature up to 300°K. The entropy of crystalline selenium at 298.16°K is 10.15±0.05 cal/g-atom/deg, of which 0.22 was obtained by extrapolating below 15°K. For this extrapolation, the anisotropic-continuum model was used.
A Study of the Formation of Iron Percarbide
Authors: Mitchell John J.
Published: January 2005

Carbon 14-labeled CO was used in a study of the carbiding of reduced iron in the temperature range 170–231°C. It was shown that the percarbide forms around nuclei scattered throughout the iron, that carbon in percarbide volumes is held firmly in place, and that a substantial fraction of the surface of partially carbided iron is occupied by percarbide.
Dependence of Joshi Effect on Electronic Part of the Discharge Current
Authors: Ramaiah N. A. , Bhatawdekar M. G. , Subrahmanyam N.
Published: January 2005

Association of Joshi effect Δi with electronic part ie of the discharge current i was investigated by elimination principle. ie was suppressed under transverse magnetic field H. In agreement with Joshi's theory, negative effect (—percent Δi) in water and iodine vapor was maximum in i and negligible in i—ie; comparatively, positive effect was unaffected by H.
The Vibrational Spectra of Pyridine and Pyridine-d5
Authors: Corrsin Lester , Fax B. J. , Lord R. C.
Published: January 2005

Pyridine-d5 has been prepared by exchange between pyridine vapor and heavy water in the presence of a palladium catalyst. Infrared and Raman spectra are reported for pyridine and pyridine-d5 over the spectral range 300–4000 cm−1. Interpretation of the spectra with the help of the product rule and by analogy with the fundamental frequencies of benzene and benzene-d6 leads to complete sets of frequencies for the 27 vibrational degrees of freedom of pyridine and of pyridine-d5. The frequency assignment for pyridine does not differ greatly from previous ones, but is believed to be more reliable because of the additional spectroscopic data.
Some Observations on the Chemical Behavior of Iodine at Low Concentrations
Authors: Kahn Milton , Wahl Arthur C.
Published: January 2005

An investigation has been made of the chemical forms assumed by I131 initially in the form of iodide ion at low concentration (the order of 10−7M) when it is oxidized under various conditions. Oxidation at room temperature in 1f sulfuric acid solution by dichromate ion or cerium(IV) results in the formation of I2 and three additional, unidentified, chemical fractions which are not readily exchangeable with I−, I2, or IO3−. Two of the unidentified fractions are extracted from aqueous sulfuric acid solution by organic solvents, one fraction being converted by aqueous sodium hydroxide to water-soluble forms exchangeable with I2. At least some of the unidentified fractions probably are the products of reactions between trace impurities, molecular or colloidal, and iodine in an oxidized reactive form such as HIO. These unidentified fractions are quite inert toward oxidation and reduction.

When iodide ion at low concentration is treated with a hot sulfuric acid solution of cerium(IV), the principal product is IO3−, or a species readily exchangeable with IO3−. The IO3− formed in this way is readily reduced at room temperature to I− by a sulfuric acid solution of iron (II).
Theory of the Rotational Spectra of Allene-Type Molecules
Authors: Mizushima Masataka
Published: January 2005

The possibility of observing the rotational spectra of allene-type molecules was suggested by the present author and Venkateswarlu. In this paper the effect of nuclear spin on the statistical weight of each rovibrational levels and the transition probability between them are calculated.
Some Thermodynamic Properties of Methane Adsorbed on Rutile Between 80 and 140°K
Authors: Pace E. L. , Heric E. L. , Dennis Kent S.
Published: January 2005

Heat capacities of methane adsorbed on rutile (titanium dioxide) have been determined from 80 to 140°K for concentrations corresponding to the fractions 0.28, 0.56, 0.84, and 1.11 of the monolayer capacity. Integral heats of adsorption, determined at 110, 120, 130, and 140°K, show correlation with the heat capacities within the experimental error. The thermodynamic functions, ΔH, ΔS, and ΔF of the differential adsorption process, have been calculated from the data. The heat capacities indicate an adsorbate having properties differing from bulk methane and possessing some degree of mobility over the surface. No first-order phase changes were in evidence for the concentrations studied. At low surface coverages, the shape of the differential heat of adsorption curve points to the presence of a heterogeneous adsorbent surface, while at coverages approaching the monolayer, dispersion forces are probably in effect. All the differential thermodynamic quantities approach the values for liquid methane at coverages greater than the monolayer in the temperature range from 110 to 140°K.
On the Use of a Single Scale Factor in Atomic Wave Functions. II. Application to Overlap Integrals
Authors: Scherr Charles W.
Published: January 2005

A method of estimation of two-center homopolar overlap integrals between SCF atomic orbitals, due to Mulliken, has been tested and verified.
Bond Energies and Bond Distances of Hydrocarbons
Authors: Glockler George
Published: January 2005

The relations between carbon-carbon bond energies [B(CC)] and distances [R(CC)] and carbon-hydrogen bond energies [B(CH)] and distances [R(CH)] are taken to be a parabola and a straight line, respectively, B(CC)=1450.762–1644.151·R(CC)+491.936·R(CC)2and B(CH)= 252.956− 141.721·R(CH),yielding B(CH)=  98.104−  0.075·B(CC)+[3.196·B(CC)−246.048]12and R(CH)=  1.396−  0.594·R(CC)+0.261·R(CC)2.This system of equations is based on the assumption that the heat of sublimation of carbon L(C)=169.75 kcal. Similar relations with L(C)=124.3 and 135.8 kcal are also derived.