bluuebunny/crossref_metadata_2025 huggingface dataset:
Compressibility of Gases. II. Mixtures of Carbon Dioxide and Helium at 30°C
Authors: Harper Robert C. , Miller John G.
Published: January 2005

An investigation of the compressibility factors of gaseous mixtures of carbon dioxide and helium has been carried out at 30°C, using the Burnett method. The pressure measuring system included a visual high-pressure manometer. Results are expressed in an empirical regression formula from which approximations to the virial coefficients can be obtained. The interaction coefficient characteristic of bimolecular encounters between helium and carbon dioxide is in reasonably good agreement with the value calculated by Lunbeck and Boerboom from the properties of the pure gases alone.
Analysis of Spin-Spin Interaction in the Nuclear Magnetic Resonance Spectra of Symmetrical Molecules
Authors: Wilson E. Bright
Published: January 2005

Some techniques are given for utilizing molecular symmetry in setting up the equations for spin-spin coupling in molecules in the liquid state. Applications of group theory to factoring the secular equation, determining selection rules, etc. are similar to those developed for the problem of molecular vibrations. Symtrifluorobenzene is used to illustrate the procedures.
Polymeric Gaseous Species in the Sublimation of Tungsten Trioxide
Authors: Berkowitz Joseph , Chupka William A. , Inghram Mark G.
Published: January 2005

Mass spectrometric study of the gaseous species effusing from a Knudsen cell filled with WO3 has shown that WO3(s) sublimes to form the gaseous molecules W3O9, W4O12, and W5O15. From the measured partial pressures for these species and their variations with temperature, ΔH, ΔF0, and ΔS0 of sublimation are obtained.
Vibrational Spectra of sym-Trioxane
Authors: Stair A. T. , Nielsen J. Rud
Published: January 2005

The Raman spectra of liquid sym-trioxane contained in a sealed, electrically heated Raman tube, and of a crystalline aggregate and a single crystal of the compound, have been photographed with a 3-prism glass spectrograph of reciprocal linear dispersion 15 A/mm at 4358 A. The infrared spectrum of trioxane vapor has been reinvestigated with the aid of a 1-m absorption cell and a Perkin-Elmer double pass spectrometer equipped with CsBr, NaCl, and LiF prisms. The 17 active fundamentals have been assigned as follows: Species a1: 2853, 2792, 1496, 975, 943, 752, and 524 cm-1; species e: 3031, 2753, 1477, 1408, 1305, 1175, 1072, ca. 1050, ca. 460, and 307 cm-1. The spectra have been interpreted in detail, and their dependence upon the state of aggregation has been discussed.
Raman and Infrared Intensities in the Vibrational Spectra of Hydrocarbons. I. Skeletal Vibrations of Straight Zigzag Chains
Authors: Theimer Otto H.
Published: January 2005

The vibrational frequencies and normal coordinates of finite, straight, zigzag chains are calculated from an Urey-Bradley potential, the boundary effects being taken into account by a perturbation method. The dominant perturbation terms fall off with 1/N2 (N = number of C atoms) and are found to be negligible for N>5. The intensities of infrared and Raman bands are calculated without using the simplifications implied in ``bond moment'' and ``bond polarizability'' theories. All the vibrations are found inactive as fundamentals in infrared absorption. The Raman active vibrations produce branches of lines with relative intensities approximately 1, 1/9, 1/25..., 1/N2 and with line spacing rapidly decreasing with increasing N. The strong Raman line observed near 890 cm-1 cannot be assigned to a vibration of the carbon skeleton. One low-frequency vibration (v∼1150/N cm-1) perpendicular to the molecular plane should be Raman active. Its low intensity (it has not been observed so far) indicates cylindrical symmetry of the polarizability about the molecular axis.
Heats of Combustion of Some Peroxides and the Heats of Formation of Acetate, Propionate, and Butyrate Radicals
Authors: Jaffe L. , Prosen E. J. , Szwarc M.
Published: January 2005

Heats of combustion of acetyl, propionyl, and butyryl peroxide were measured using a bomb calorimeter. The heats of formation obtained are: ΔHf = — 127.9 for acetyl peroxide, — 148.2 for propionyl peroxide, and — 161.0 for butyryl peroxide (in kcal/mole for the liquid state at 25°C). The heats of formation of the acetate, propionate, and butyrate radicals have been computed and the relative stability of the acetate compared to the benzoate radical is discussed.

The RC(O)O–H bond dissociation energies in the respective acids and the sums of electron affinities plus solvation energies of the respective ions are computed.

These calculations seem to indicate that acidic properties of carboxylic acids are due to the high electron affinities+solvation energies of R·COO radicals, and not to the low R·CO·O–H bond dissociation energies, since the latter are comparatively high.
Effect of Adsorbent Perturbation on B.E.T. Theory
Authors: Peticolas Warner L.
Published: January 2005

The statistical mechanical derivation of the B.E.T. equation has been extended to include perturbations of the adsorbent by the adsorbate. The thermodynamic functions have been recalculated to include this effect. The thermodynamic functions for the adsorbent as well as the adsorbate have been calculated.
Vibrational Intensities. VIII. CH3 and CD3 Chloride, Bromide, and Iodide
Authors: Dickson A. D. , Mills I. M. , Crawford Bryce
Published: January 2005

Absolute intensity measurements have been made on the fundamental vibrations of methyl chloride, bromide, and iodide, and their fully deuterated derivatives, by integrating the optical density over the absorption bands. The bands were fully pressure broadened by using up to 80 atmos of foreign gas. Band separations were made graphically. The results are analyzed in terms of the dipole moment derivatives with respect to symmetry coordinates in the molecule, (∂p/∂Si). The data on the different isotopic species are shown to yield consistent results, and this requirement of consistency has also been used as an aid in the analysis. In the E-class vibrations the signs of the dipole moment derivatives have been determined unambiguously by assuming the permanent dipole to be directed CH3+–X—.
Normal Coordinates in the Methyl Halides
Authors: King W. T. , Mills Ian M. , Crawford Bryce
Published: January 2005

The potential-energy functions found by Chang for the methyl halides have been put into valence-type form and revised to eliminate inconsistencies and to accord with the true (nontetrahedral) geometry and the normal frequencies (corrected for Fermi resonance and anharmonicity). The resulting valence-type force constants and normal coordinates are given for light (CH3) and heavy (CD3) chlorides, bromides, and iodides.
Fluorescence Intensity Ratio of Sodium Doublet Observed in the Optical Dissociation of Sodium Iodide Vapor
Authors: Hanson Howard G.
Published: January 2005

The intensity ratio D2/D1 for the sodium doublet has been measured for radiation from excited sodium atoms which result from the optical dissociation of sodium iodide vapor by ultraviolet light in the 2082→2500 A region. With shorter wavelength ultraviolet light as exciting source, the D2/D1 ratio is 0.98 and increases to above 1.5 with longer exciting wavelengths. Addition of foreign gases cause the observed D2/D1 ratio to increase to 1.89 for large foreign gas pressure. Cross sections for the transfer of excited sodium atoms from the 32P32 to the 32P½ state and vice versa due to collisions with foreign molecules have been measured as they depend on the relative velocity between excited sodium atom and foreign molecule. The Doppler broadening of the separate D lines emitted in the atomic fluorescence of sodium iodide has been estimated from absorption measurements. Both lines show equal broadening within the experimental error of the observations. Measurements were made with a photomultiplier tube. The sodium doublet was resolved with a reflection grating monochromator.
Pi Complexes between Organic Free Radicals
Authors: Hausser K. H. , Murrell J. N.
Published: January 2005

The spectroscopic and magnetic properties of N-ethylphenazyl and Wurster's blue perchlorate show characteristic changes at low temperatures. Using Mulliken's charge-transfer theory, we have shown that the formation of π complexes can account for these changes.

The intense long wavelength absorption band which appears at low temperatures in both cases, is attributed to a transition to a state which is an antisymmetrical combination of two charge-transfer configurations, in which all the electrons are paired.

We have compared the properties of these π complexes with the properties of the biradicals related to 4,4′-bis-diphenylmethylenediphenyl (chichibabin hydrocarbon.)
Theory of Multi-Component Fluid Mixtures. II. A Corresponding States Treatment
Authors: Wojtowicz Peter J. , Salsburg Zevi W. , Kirkwood John G.
Published: January 2005

The theoretical basis for a theorem of corresponding states for mixtures is examined in a rigorous manner by the use of statistical mechanics. With the aid of the general theory of mixtures presented in a previous paper, the theorem of corresponding states is found to be a consequence of the following assumptions: (a) the internal molecular partition functions depend only on the temperature, (b) the system is in a condition of random mixing, and (c) the several intermolecular interactions can be described by a set of pair-potentials of the same analytical form.

In addition to providing a firm theoretical foundation for the corresponding states treatments of Prigogine et al. and Scott, several new approaches to the use of corresponding states in the statistical thermodynamics of mixtures are also presented. In particular, the chemical potentials in binary mixtures of molecules of equal size, and of unequal sizes, are developed. The coefficients in the Margules expansion of the activity coefficients are found to be expressible as functions of the intermolecular interaction parameters and certain experimentally determined thermodynamic properties of the pure components.

The relationships of the Regular solution and Conformal solution theories to the present development are also demonstrated.
Heterophase Fluctuations near the Freezing Point
Authors: Lukasik S. J.
Published: January 2005

Numerical calculations of the magnitude of the effects caused by heterophase fluctuations predicted by Frenkel to occur near a first-order phase change are presented for o-cresol and benzene near their freezing point. The magnitude of the effect depends inversely on the number of degrees that the temperature is above the freezing point, the solid-liquid surface energy, and a parameter g0 that is related to the size of the regions in which pretransition phase changes occur. Appropriate values of the parameters in the theory are discussed and compared with experimental information where possible.
Estimates of Hammett's Sigma Values from Quadrupole Resonance Studies
Authors: Bray P. J. , Barnes R. G.
Published: January 2005

A linear correlation exists between the Cl35 pure quadrupole resonance frequency in substituted chlorobenzenes and the Hammett parameter sigma for the substituent. The relation is expressed as f=1.024σ+34.826 Mcps.For the 52 frequencies used in determining this relation, the correlation coefficient is r = 0.96 and the root-mean-square deviation of the experimentally determined f values from those predicted by the equation is 360 kcps.

A proper ortho sigma parameter for use in the f vs σ correlation is apparently the value derived from the Hammett relation σ = lnK/K0 in which K and K0 are the equilibrium constants for ionization of the substituted and unsubstituted benzoic acid in water at 25°C. This parameter is linearly proportional to the polar substituent σ* of Taft for the ortho substituent.

In the many multiply substituted chlorobenzenes investigated, the proper total sigma value has been taken as the sum of the individual parameters. Few cases are apparent in which the linear relation of f to σ is seriously violated. Additivity of the electron displacement properties of substitution, suggested by Jaffe and indicated by studies of the magnetic shielding in fluorobenzenes, is apparently confirmed.

Sigma values for 29 substituents have been estimated from the Cl35 pure quadrupole resonance frequency measured in the substituted chlorobenzene.
Infrared Absorption Spectra of Nitric Acid and Its Solutions
Authors: Marcus R. A. , Fresco J. M.
Published: January 2005

Infrared spectra of reactive liquids such as anhydrous nitric and sulfuric acids were determined using silver chloride windows and, in some cases, Teflon spacers. The absorption frequencies of nitric acid agree well with those found from Raman spectra.

A nitronium ion frequency was observed at 2360 cm—1. The intensity of this band is enhanced by the addition of nitronium fluoborate, sulfuric acid, phosphorous pentoxide, or small amounts of acetic anhydride. It is reduced by addition of sodium nitrate, potassium dihydrogen phosphate, water, or larger amounts of acetic anhydride. Its behavior in these media provides information about pertinent equilibria. A nitronium ion combination band was observed near 3745 cm—1 when the concentration of this ion was particularly large. Bands arising from unionized nitric acid are completely absent when a small amount of nitric acid is added to 100% H2SO4.

Various bands found in aqueous nitric acid solutions are attributed to hydrogen-bonded structures, both because of their behavior in different media and by analogy with effects observed in Raman studies.
Fundamental of N15O
Authors: Fletcher W. H. , Begun G. M.
Published: January 2005

The fundamental vibration-rotation band of N15O has been examined with a grating spectrometer. The molecular constants obtained are in good agreement with existing data and the isotope relations.
Study of the Mass Spectra of the Lower Aliphatic Alcohols
Authors: Friedman L. , Long F. A. , Wolfsberg M.
Published: January 2005

Mass spectra and appearance potentials have been determined for methanol, ethanol, and propanol. These data are used in semiempirical application of the statistical theory of mass spectra. The theory facilitates assignment of plausible mechanisms for the production of the various ion fragments. It is possible to obtain computed spectra in agreement with experimental data using an internally consistent set of structural parameters.
Application of Nuclear Magnetic Resonance to the Study of Acid-Base Equilibria
Authors: Grunwald Ernest , Loewenstein A. , Meiboom S.
Published: January 2005

Acid-base equilibria in aqueous solutions of methylamine, dimethylamine, and trimethylamine have been studied by nuclear magnetic resonance. It is shown that the chemical shift of the methyl protons is a linear function of the concentration ratio of acid to base plus acid. The NMR spectrum of tetramethylammonium ion is also given.
Adsorption of Nickel on Molybdenum in the Field Emission Microscope
Authors: McIrvine E. C. , Bradley R. C.
Published: January 2005

An investigation of the adsorption of nickel on molybdenum is compared with theoretical considerations of adsorption phenomena. Nickel was found to adsorb coherently on molybdenum, preferentially on the (111) planes of the substrate. For coverages of about ⅕ of a monolayer, the following activation energies were determined: Qd=(2.10±0.05) ev (desorption)Qm=(1.31±0.08) ev (surface migration 14 completed)Qm=(1.42±0.05) ev (surface migration 12 completed)Qm=(1.48±0.06) ev (surface migration 34 completed).The desorption energy did not vary with degree of completion. Heavy adsorbed layers of nickel were investigated. The equilibrium position of heavy layers was found to be field dependent.
Kinetics of Complex Isotopic Exchange Reactions
Authors: Abell D. F. , Bonner N. A. , Goishi W.
Published: January 2005

A general equation has been developed for the kinetics of complex isotopic-exchange reactions in which each of three nonequivalent species is exchanging with the other two.
Infrared Spectrum and Force Constants of the Nitrite Ion
Authors: Weston Ralph E. , Brodasky Thomas F.
Published: January 2005

The infrared spectra of the following compounds have been investigated: microcrystalline NaNO2, KNO2, and AgNO2; and aqueous solutions of NaNO2 and KNO2. The spectra of N15-labeled compounds have also been obtained. The spectrum of the high-temperature modification of NaNO2, which exists above 160°, has been observed. The fundamental frequencies for NO2— (in crystalline NaNO2) are: ν1(a1)=1328±2 cm−1 (N14),1303±2 (N15);ν2(a1)=828.2±0.4 (N14),823.6±0.4 (N15);ν3(b1)=1261±3 (N14). These are used to calculate the following force constants, in units of millidynes/A: fd=7.69±0.10,fα/d2=1.75±0.04,fdd=1.94±0.13,fdα/d=0.505±0.113.
Hydrogen Vibration Spectra of Rochelle Salt
Authors: Baker A. N. , Webber D. S.
Published: January 2005

The polarized infrared spectra of Rochelle salt from 4550 cm—1 to 8100 cm—1 have been observed with a grating spectrometer. These spectra and the Raman spectra reported by other authors have been partially interpreted. Tentative conclusions concerning the location of the hydrogen atoms in the crystal at a temperature of 300°K are drawn from the analysis of the spectra.
Thermodynamics for Elastic Solids in the Electrostatic Field. I. General Formulation
Authors: Li James C. M. , Ting Tsuan Wu
Published: January 2005

A condensed collection of all the thermodynamic relations among first derivatives for elastic solids under the outside variation of only temperature, stress, and the electrostatic field is presented. Simple relations among all the possible empirical coefficients are tabulated. Tables of first derivatives with respect to variables of practical interest, from which the Jacobians and all other first derivatives can be obtained in terms of empirical quantities, are given and their applications are illustrated with examples.
Electronic Band Structure of Boron Carbide
Authors: Yamazaki Masatoshi
Published: January 2005

The tight-binding approximation is applied to a study of electronic energy bands of the boron carbide B4C crystal. The 60×60 determinantal secular equation for the energy is reduced by group-theoretical treatments of the spatial symmetry at certain special values of the wave vector k. Calculations are carried out at two points in the Brillouin zone. At the zone center point there is a substantial energy gap, about 2.5 ev, between the occupied and unoccupied levels, and at the zone boundary point k = (π/a)(1,1,1) this gap becomes very narrow, i.e., about 1 ev. Considering compatibility relations for the types of symmetry, there may be the energy gap, being substantially broad at the zone center point and very narrow at the zone boundary point k = (π/a)(1,1,1), between the all-filled valence and the all-empty conduction bands, in accordance with the existence of the complicated structure, the great hardness, and the appreciable electric conductivity of this crystal.
Formation of Reversible Colored Modifications at Low Temperatures by Bombardment with Electrons
Authors: Hirshberg Yehuda
Published: January 2005

The effects of electron irradiation at low temperatures upon a number of bianthrone and spiropyran compounds have been examined. The colors induced have been found to be very similar in properties to those obtained by ultraviolet irradiation of the same compounds.
Higher Approximations for the Transport Properties of Binary Gas Mixtures. II. Applications
Authors: Mason Edward A.
Published: January 2005

Detailed numerical calculations are used to test the convergence of the higher approximations for the diffusion coefficient and thermal diffusion factor. The results show Kihara's second approximation to be the best to use and of sufficient accuracy, except for the thermal diffusion factor of mixtures with a heavy component in excess. For such a mixture both the Chapman-Cowling and the Kihara approximations are unreliable, and a new method is proposed for this case. The thermal diffusion of hydrogen-carbon dioxide mixtures is taken to illustrate the possible large errors resulting from use of inaccurate theoretical expressions. For precise work, the first approximations cannot in general be relied upon.
Transport Processes in Multicomponent Liquids
Authors: Sundheim Benson R.
Published: January 2005

The phenomenological equations are obtained for interacting flows of matter, electricity, and heat. The differential equations of motion of these systems are written down and transformations which effect separation of variables are found, permitting exact intergrations to be performed. An examination is made of coefficients of transport and the significance of a reference species is discussed.
Characteristics of Plastic Scintillators
Authors: Basile Louis J.
Published: January 2005

Information on the light output of a group of organic solutes in polyvinyltoluene has been obtained. The primary solutes studied are p-terphenyl and 2-phenyl-5-(4-biphenylyl)-1,3,4 oxadiazole (PBD), the latter being the most efficient. Of the secondary solutes studied, 4,4′-diphenylstilbene and 2,5-dibiphenylyl oxazole (BBO) are the most efficient. The best plastic scintillator developed contains a combination of 2-phenyl-5-(4-biphenylyl)-1,3,4 oxadiazole (PBD) and 4,4′-diphenylstilbene.

The fluorescence spectra of these plastic scintillators were determined. When a secondary solute is added to a plastic scintillator the emitted light is mainly that of the secondary solute.

The effect on the light output of the plastic scintillator upon addition of diphenylmercury was also investigated. Regardless of which combination of solutes was used, the mercury compound proved to be a serious quencher of light output.
Higher Order Rotation-Vibration Energies of Polyatomic Molecules. III
Authors: Amat Gilbert , Nielsen Harald H.
Published: January 2005

The Hamiltonian for a polyatomic molecule has been developed to fourth order of approximation in Part I of this series of papers. This Hamiltonian, H=H0+λH1+λ2H2+λ 3H3+λ4H4+···, was transformed, in Part II, into H′=H0+λH1′+λ2H2′+λ3H3′+λ4H4′+···, by a contact transformation, THT—1, where to second order H0+λH1′ has matrix elements which are diagonal in the quantum numbers of vibration, vs, in the representation which diagonalizes H0. H′ is further transformed in this paper (Part III), to facilitate computation, by a contact transformation, TH′T−1, in such a manner that H0†+λH1†+λ2H2† will be diagonal with respect to the quantum number, vs, in the representation which diagonalizes H0, although not, in general, diagonal in the quantum numbers of angular momentum of vibration, ls, in the case of the two dimensionally isotropic oscillator, and in the quantum numbers of angular momentum of vibration, ls, and ms, in the case of the three dimensionally isotropic oscillator.
Single-Pulse Shock Tube Studies of the Kinetics of the Reaction N2+O2⇄2NO between 2000–3000°K
Authors: Glick H. S. , Klein J. J. , Squire W.
Published: January 2005

The single temperature pulse technique, developed at the Cornell Aeronautical Laboratory, has been used to study the kinetics of the formation of nitric oxide in the temperature range from 2000° to 3000°K. It has been found that the kinetics of the reaction are consistent with the chain mechanism proposed by Zeldovich. The rate-determining step in the chain is: O+N2→NO+N, with ΔH25000=75.8 kcal/mole. The activation energy for this step is found to be 74±5 kcal/mole. The collision cross-section, as calculated from classical reaction rate theory, is 10—16 cm2, which corresponds to a steric factor of about 0.05, assuming σN2,O=5 A.
Microwave Spectra of Molecules Exhibiting Internal Rotation. II. Methylallene
Authors: Lide David R. , Mann D. E.
Published: January 2005

The microwave spectrum of methylallene, CH3CH:C:CH2, has been investigated in the region 16–33 kmc, and the J=1→2, 2→3, and 3→4 transitions measured. Most of the observed lines are split slightly as a result of internal rotation. Analysis of the splittings by the methods of Hecht and Dennison leads to an internal potential barrier of 556.0±2 cm—1 or 1589±6 cal/mole. The principal moments of inertia (in units of amu A2) are 14.93, 120.321, and 128.713. The electric dipole moment is 0.401 D and makes an angle of 10°8′ with the a principal axis.
Density of Liquid Ozone
Authors: Brabets Robert I. , McDonough John M.
Published: January 2005

The density of liquid ozone has been measured over the range 77.4 to 174.2°K by means of ozone thermometers. The construction of the thermometers and the operating techniques are described. An equation which relates the specific volume of liquid ozone to the absolute temperature is presented. The equation, V=0.551+(6.25×10—4)T+(3.35×10—6)T2, represents the experimental data to within 0.2%. A density of 1.354±0.001 g/ml is reported for liquid ozone at its normal boiling point, 161°K.
Dielectric Dispersion of Boric Acid in Water. The Rate of Recombination of H+ and H2BO3— at 35°C
Authors: Gilkerson W. R.
Published: January 2005

A novel method has been developed for the measurement of the rates of fast ionic reactions in solution. The application of an alternating electrical field to a solution containing a system in mobile equilibrium, such as HA⇌H++A—, causes a small shift in this equilibrium. The shift, to produce more ions, lags behind the changing field and causes an absorption of energy from the field. Measurement of the dielectric constant and loss factor of the solution allows the determination of the relaxation time due to the shift in equilibrium. This is related to conventional rate constants. The method has been applied to the reaction H++H2BO3— in water at 35°C. The rate constant has been determined to be 1.3×1010 M—1 sec—1 at this temperature.
Interaction Energies and Scattering Cross Sections of Hydrogen Ions in Helium
Authors: Mason Edward A. , Vanderslice Joseph T.
Published: January 2005

The interaction energies for the H+–He and H2+–He system have been calculated for a range of internuclear distances and, in the H2+–He case, for two different configurations. The results are used to analyze the ion-scattering measurements of Simons and co-workers. It has been found that the predicted scattering cross sections are in remarkable agreement with the measured ones, provided allowance is made for a finite width of the ion beam, as suggested by Amdur and Harkness. This agreement implies that the method of interpreting measured cross sections in terms of molecular forces is correct, and that specific apparatus effects have been correctly analyzed. The present calculations suggest, in contrast to previous assumptions, that the important forces are ones of repulsion rather than attraction, with the exception of those cases where chemical binding is clearly involved. As expected, to obtain precise force information of physical significance from such scattering measurements, it is again necessary to make allowance for the finite width of the ion beam. This has been illustrated for the scattering of H3+ ions in helium. Finally, the cross-section equations have been integrated for the case of scattering by an exponential potential and by a Lennard-Jones (8–4) potential.
Intermolecular Correlation in Light Scattering from Dilute Polymer Solutions
Authors: Albrecht Andreas C.
Published: January 2005

The effects of intermolecular correlation on light scattered from flexible chain molecules are considered. The random flight model is treated correctly to the double contact approximation. Two smoothed density models are carried to the same approximation and comparisons are made. In every case a decrease of ``apparent'' A2 with increasing angle of observation is predicted in qualitative agreement with experiment.
Influence of External Treatments on Electret Behavior
Authors: Wild Jack W. , Stranathan J. D.
Published: January 2005

The following effects of external treatments upon electrets have been observed. (1) When the surface of an electret which exhibited a homocharge was planed in a lathe, the sign of the equivalent surface charge changed to that of the heterocharge. This heterocharge then decayed and the homocharge finally became dominant again. The magnitude of the final homocharge was smaller than that of a control electret which was not planed. (2) Repeated planing of an electret, with time allowed for recovery between successive planings, resulted in repetition of the cycle described in (1). (3) Wax dummies (not subjected to an electric field during manufacture) which were given a frictional charge and then planed, showed no reversal of sign; they did exhibit a small recovery after being planed. (4) Electrets subjected to 100% relative humidity exhibited an abrupt decrease in equivalent surface charge. Removal of the moisture resulted in a gradual, slight recovery. (5) The curve relating the equivalent surface charge and the logarithm of the pressure of the air surrounding an electret, has the same form as the curve of the sparking potential for air versus the logarithm of the pressure. Thus, all the treatments described resulted in a decay of the homocharge, followed by a partial recovery upon removal of the disturbing influence. The observed behavior can be explained in terms of the electret mechanism proposed by Gross.
Rates and Mechanisms of Protolysis of Di- and Trimethylammonium Ions Studied by Proton Magnetic Resonance
Authors: Loewenstein A. , Meiboom S.
Published: January 2005

A kinetic analysis of the protolysis reactions of di- and trimethylammonium ions in aqueous solution has been carried out using the nuclear magnetic resonance technique. The results complement those of a similar study of methylammonium ion reported on in an earlier paper. In the pH range studied (between 3 and 5) the main mechanism is: RNH++RN⇆RN+RNH+. The reaction involves water in nearly every exchange. The measured rate constants are: 6.0×108 and 3.1×108 sec—1M—1 for di- and trimethylammonium, respectively.
Nuclear Magnetic Resonance Study of Liquid Crystal Transitions
Authors: Runyan W. R. , Nolle A. W.
Published: January 2005

The spin-lattice relaxation time (T1) and the transverse relaxation time (T2) are determined, by the spinecho nuclear magnetic resonance method, for the isotropic-liquid state of the liquid-crystal compounds p-azoxyanisole (PAA), cholesteryl benzoate, cholesteryl n-butyrate, and cholesteryl propionate. The T1 values are 1.2 sec for PAA, and 0.06 to 0.15 sec for the cholesteryl compounds. The T2 values are 0.02 to 0.03 sec for the cholesteryl compounds, and at least 0.05 sec for PAA. The results are consistent with those for other isotropic liquids. As the temperature decreases toward the transition to the anisotropic phase, a pretransitional decrease of T2 is observed for the cholesteryl compounds, and a similar decrease of T1 for PAA. An explanation in terms of Frenkel's theory of heterophase fluctuations is discussed. Thermal expansion curves and interphase surface tension for PAA are also considered, and hysteresis-like behavior of the phase transition.
Vibrational Spectra and Structure of Phosphonium and Deutero-Phosphonium Iodides
Authors: Martinez J. V. , Wagner E. L.
Published: January 2005

The infrared spectra of sublimed films of PH4I and PD4I were obtained at —78° and —190°C in the region 4000–400 cm—1. Powder and Nujol mull spectra were obtained at room temperature. The low temperature spectra could be interpreted on the basis of a Vd site symmetry for the PH4+ ion as occurs in the phase III NH4Br and NH4I structures. The room temperature spectra are also compatible with the room temperature x-ray structure, D4h7. No evidence for any sort of transition was found. The hydrogen bond energy in PH4I is less than 0.5 kcal/mole.
Combined Catalysts as Revealed by Electron Diffraction
Authors: Yamaguchi S.
Published: January 2005

Combined catalysts are studied by electron diffraction using alternate wavelengths. Three types of catalysts are distinguished from the results obtained. Either the substrate or the promotor predominates in the surface of the catalyst particle. There is another distribution of particles of solid phases in which neither phase envelops the other.
Organic Ions in the Gas Phase. V. C6H5+ Ion from Toluene
Authors: Rylander Paul N. , Meyerson Seymour
Published: January 2005

The C6H5+ ion obtained from toluene by electron impact is not formed simply by cleavage of the phenylmethyl bond, as has been assumed, and may not be a phenyl ion at all. The apparent identity of this ion with the C6H5+ ion derived from benzene leads to the inference that the latter, also, may not be a phenyl ion.
Influence of Hydrogen and Deuterium on Flame Velocities of Dry Carbon Monoxide-Oxygen Mixtures
Authors: Watermeier Leland A.
Published: January 2005

A constant pressure method employing a schlieren photographic technique was used to determine the space velocities of dry carbon monoxide-oxygen mixtures with added hydrogen and deuterium. Flame velocities were obtained by using the data together with theoretical expansion ratios. The results are presented and correlated with current diffusion and thermal theories. Neither theory explains the velocity ratios adequately although better agreement is found with the diffusion theory than with the thermal theory. The velocity ratios depended strongly upon H and D atom diffusion. A simple mechanism is proposed for the combustion processes in which it is postulated that CO+O2+H2 flames are initiated by a hydrogen-oxygen reaction.
Electronegativity of Radicals. A Method of Calculation
Authors: Wilmshurst J. K.
Published: January 2005

Gordy's expression, relating the electronegativity of an atom with the number of electrons in the valence shell and the covalent bond radius, has been extended to the calculation of the group electronegativity of a radical. Both the state of hybridization and the effect of the electronegativity property of other atoms on the bonding atom in the radical have been accounted for. The group electronegativities calculated by this expression are in agreement with those obtained from the ``sensitive'' CH bending vibrational frequencies, but disagree with group electronegativities obtained from other spectroscopic data. The causes of these differences have been discussed.
Defects on a Dipole Lattice
Authors: Isihara A.
Published: January 2005

Effects of defects on dipole interactions in a simple cubic lattice are calculated using the spherical model developed by Berlin and Thomsen, Lax, and others. When the concentration of defects is small, thermodynamical functions are linearly dependent on the concentration. The Curie temperature in the three-dimensional lattice is raised or lowered linearly with the concentration according to whether the defects have stronger or weaker dipole interactions with their neighbors than the interactions which the rest of atoms have. Lattice vacancies also reduce the Curie temperature. The specific heat and electric susceptibility of defect lattice are calculated. In the presence of an homogeneous electric field, there exists a critical field which is influenced by defects.
On the Optical Properties of Solids. II
Authors: Rosenstock Herbert B.
Published: January 2005

The absorption of light by a crystal due to atomic motion is calculated by first-order perturbation theory in the approximation in which atoms are considered as charged mass points. The effect of each normal oscillator is shown to depend on the value of a sum over normal mode transformation coefficients which becomes identical with the dipole moment associated with the oscillator when the crystal is small compared to the longest absorbed wavelength. To get results in terms of frequency, this expression must be weighted by the density of states of the normal oscillators. The general results are evaluated for the case of a simple model of an ionic crystal; in addition to the strong absorption peak at the ``limiting frequency,'' peaks at frequencies corresponding to critical points of the constant energy surfaces in k space are shown to appear provided boundary conditions are taken into account, and the effects of crystal size are shown to enhance the importance of these subsidiary peaks. The bearing of these effects on other optical properties, and on the impurity problem, is discussed briefly.
Rate Constants at Low Concentrations. IV. Reactions of Atomic Oxygen with Various Hydrocarbons
Authors: Ford Hadley W. , Endow Noboru
Published: January 2005

Nitrogen dioxide was photolyzed at trace concentrations in a carrier gas at a pressure of 1 atmosphere. The concentration of atomic oxygen could be estimated by using rate constants previously obtained [H. W. Ford and N. Endow, J. Chem. Phys. 27, 1156 (1957)]. An iterative method was used to calculate the concentration of atomic oxygen in the presence of trace amounts of hydrocarbons. Rate constants for the reactions of atomic oxygen with various hydrocarbons are reported, together with other closely related rate constants reported previously.
Interaction of Vibrational and Electronic Motion in Alkali Halide Molecules
Authors: Berry R. Stephen
Published: January 2005

A treatment is developed to interpret the observation that in corresponding regions of the ultraviolet the absorption spectra of sodium iodide and potassium iodide show a band system and a continuum, respectively. The former results from a bound excited state in which the form of the electronic wave function changes drastically with internuclear distance. The latter arises because the nuclear motion can no longer be considered adiabatic with respect to electronic motion, so that the noncrossing rule does not apply.
Effect of Change in Moment of Inertia on the Intensity Distribution in P and R branches of C∞v Molecules
Authors: Gallup G. A.
Published: January 2005

The effect of the change in moment of inertia part of the interaction between vibration and rotation on the intensities of parallel bands of linear polyatomic molecules has been determined to the first order. The results are quite similar to those of Herman and Wallis for diatomic molecules. The interaction term depends on among others a quantity, ξk, different in general for each band. Perpendicular bands do not show a first-order correction. A ``sum rule'' for the ξk has been determined.
Crystal Growth of Silver Metal. Mechanism and Kinetics
Authors: Courtney Welby G.
Published: January 2005

The crystal growth of silver-metal whiskers and ``ferns'' occurring in the reduction of Ag(I) with Fe(II) from aqueous perchlorate solution was directly observed under the microscope. Whiskers frequently grew at well-defined angles to the previous direction and occasionally stopped growing abruptly although nearby whiskers continued to grow. In fern growth, short spikes grew in a regular manner from only one side of a parallel-sided main stem. Linear growth rates of whiskers were essentially independent of an estimated eightfold variation in supersaturation, but the growth rate of a whisker occasionally increased abruptly in approximately integral ratios. Whisker and fern growth are qualitatively attributed to perfect and twinned screw dislocations, respectively, but no explanation is offered for the formation of whisker and fern habits. It is shown that an interpretation of growth habit will require the Burton, Cabrera, and Frank treatment of infinite surfaces to be extended to the edges and corners of a crystal. Limited kinetic data suggest that the size of the critical surface nucleus was independent of supersaturation, which is contrary to the classical theory of crystal growth. A possible explanation for constant-sized critical surface nuclei is offered.
Adsorption and Diffusion of Oxygen on Tungsten
Authors: Gomer Robert , Hulm J. K.
Published: January 2005

The surface diffusion and adsorption of oxygen on tungsten have been studied by a field emission technique, by utilizing the high sticking coefficient, and negligible vapor pressure of O2 at 4.2–20°K. Three types of migration were noted. At ∼27°K diffusion occurs with a sharp boundary and an activation energy Ed≈0.9 kcal. This is believed to be migration of physically adsorbed O2 over the chemisorbed layer, with precipitation on the bare surface. The distance traversed by the boundary was found to be limited by desorption above ∼40°K. A study of this effect yielded an estimate of 2.3 kcal for the heat of adsorption, Ha, in the physisorbed layer. At 400–500°K and high coverages, diffusion occurs within the monolayer with activation energies of 23–25 kcal. Boundaries moving radially outward from the close-packed faces are observed, and believed to result from precipitation of O atoms in trap sites on the rough regions of the surface. At low coverages boundary free diffusion with Ed≃30 kcal is observed and interpreted as migration from trap sites. The latter are believed to constitute ∼60% of all sites. Activation entropies for the various diffusion processes are estimated to vary from ∼7–13 eu.

It was found that 80% of the chemisorbed layer can be formed without appreciable activation at 27°K. The layer is stable up to 700°K, where desorption and oxidation start. The latter is markedly dependent on the amount of oxygen on the surface. At 300°K there is a slow oxygen uptake probably associated with incipient oxidation.
Soret Effect in Doped Ionic Crystals
Authors: Howard R. E.
Published: January 2005

The Soret effect in an ionic crystal of the type MX doped with divalent impurity ions is considered from the point of view of lattice defects. On the assumption that the impurity ions move in the form of tightly bound impurity-vacancy complexes, the relative concentration gradient of impurity ions is expressed in terms of the heat of transport of the complex and in terms of quantities which may be determined from electrical conductivity measurements. Following the kinetic theory of Wirtz, the heat of transport of the complex is simply related to the heats of transport of the elementary jumps involved in the motion of the complex. An estimate is made of the magnitude of the Soret effect in AgBr containing CdBr2. It is found that the relative concentration gradient should be large enough to be measured experimentally.
Mercury Photosensitized Polymerization of Acetylene
Authors: Shida S. , Kuri Z. , Furuoya T.
Published: January 2005

An investigation has been made of the mercury (3P1) photosensitized polymerization of acetylene. Benzene was found in the reaction products in addition to polymer and hydrogen. Effect of acetylene pressure and light intensity on the rate, effect of pressure on the formation of hydrogen and benzene, and effect of temperature on the rate of benzene formation were studied. The fraction of acetylene reacting to form benzene was constant at 0.29 in the range of the acetylene pressure studied. The quantum yield of the over-all reaction was 4.8 including the yield of benzene and 4.3 excluding it. The reaction mechanism is discussed.
Residual Concentration of a Daughter Substance Removed by a Bimolecular Reaction
Authors: Rothstein Jerome
Published: January 2005

Consider an initial concentration N0 of a parent substance transforming monomolecularly into a daughter substance. The differential equation giving the concentration n of the latter subject to the condition that the daughter substance is removed by a bimolecular reaction is reduced to the form y′ = e—x—y2. The solution is given in graphical and tabular form, and several approximations analyzed. The measurement of decay constants in terms of reaction constants and vice versa is discussed. Possible applications to studies of chemical kinetics, lattice defects, order-disorder transformations in solids, electronic processes in semiconductors and phosphors, recombination of ions in liquids and gases, and tracer studies in vitro and in vivo are mentioned.
Electrochemical Behavior of the Palladium-Hydrogen System. I. Potential-Determining Mechanisms
Authors: Schuldiner Sigmund , Castellan Gilbert W. , Hoare James P.
Published: January 2005

The potential of saturated α-palladium in hydrogen-stirred solution compared to a Pt/H2 electrode in the same solution is 0.0495±0.0005 v. The potential-determining reaction on α-palladium is independent of hydrogen pressure. The potential-determining equilibrium is postulated to be, H++e= lim Pd(Pd−H)α. Pure palladium spontaneously absorbs hydrogen in hydrogen-stirred solution until the saturation limit of the α phase is reached. This limiting atomic ratio of H/Pd=0.025±0.005. Between a H/Pd atomic ratio of 0.03 to 0.36 both the α and β phases coexist and the mixed potential is determined by that of the α domains. In the H/Pd region 0.36 to 0.6, the potential is a function of the hydrogen content of the palladium.
Electrochemical Behavior of the Palladium-Hydrogen System. II. Thermodynamic Considerations
Authors: Castellan Gilbert W. , Hoare James P. , Schuldiner Sigmund
Published: January 2005

The thermodynamic relationships between the potentials of the palladium-hydrogen alloys and the known equilibrium properties of the system, palladium-hydrogen gas, are derived and discussed. A value of 0.048 v for the potential of the saturated α alloy derived from the gas phase data is in substantial agreement with the observed value of 0.050 v. The spontaneous loss of hydrogen from the electrolytically charged alloy of composition, H/Pd∼0.6, to form an alloy of lower hydrogen content shows that there is an unusual free-energy situation involved in this system. This is discussed and an explanation of the free energy scheme is suggested.
Crystal and Molecular Structure of Diboron Tetrafluoride, B2F4
Authors: Trefonas Louis , Lipscomb William N.
Published: January 2005

X-ray diffraction study of a single crystal of B2F4 indicates a planar, centrosymmetric molecule with B–B=1.67±0.045 A, B–F=1.32±0.035 A and angle F–B–F=120°. There are two molecules in a monoclinic unit cell of symmetry P21/n and parameters of a=5.49, b=6.53, c=4.83, and β=102.5°.
Theory of the Dielectric Constant of Imperfect Gases and Dilute Solutions
Authors: Hill Terrell L.
Published: January 2005

General statistical mechanical equations are derived for the polarization, Clausius-Mossotti function, dielectric constant and electrostriction of an imperfect gas. Results are given in the form of series expansions which are closely related to the conventional virial expansion of a gas. The coefficients in the expansions for the polarization, etc., can be evaluated by a consideration of sets of only two, three, etc., molecules in the presence of the external electric field. A similar treatment of a binary solution is also included.
Photon Impact Studies of Molecules Using a Mass Spectrometer
Authors: Hurzeler H. , Inghram Mark G. , Morrison J. D.
Published: January 2005

A vacuum ultraviolet monochromator has been combined with a mass spectrometer, in order to study photoionization processes. A detailed description is given of this instrument. Photoionization efficiency curves for parent and fragment ions from a number of molecules have been measured, using a photon beam with an energy spread of 0.05 ev. It is shown how the results can be interpreted in terms of potential surfaces and electronic transition probabilities. In favorable cases vibrational structure may be resolved.
Soft X-Ray Absorption Edges of Metal Ions in Complexes. III. Zinc (II) Complexes
Authors: Cotton F. Albert , Hanson Harold P.
Published: January 2005

The K x-ray absorption edges of the Zn+2 ion in various complexes have been measured with a two-crystal spectrometer. The significance of the fine structure of these edges with regard to the stereochemistry and electronic structure of the complexes is discussed.
Viscosity of Dilute Solutions of Long Chain Polymer Molecules
Authors: Bhatnagar H. L. , Biswas A. B. , Gharpurey M. K.
Published: January 2005

An expression for the relative viscosity ηr has been obtained on the basis of the ``theory of rate processes'' using an ``equivalent sphere'' model, which relates ηr to parameters such as the shearing force, absolute temperature, and the volume fraction of the polymer. In the limit of zero rate of shear, a relation between the Flory constant φ and Huggin's constant k″ has been obtained. Some important applications of the derived equations have been discussed.