bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infrared Absorption Spectra of Complex Cobalt Compounds
Authors: Hill Douglas G. , Rosenberg Alexander F. 
Published: January 2005

The infrared absorption spectra of finely powdered complex cobalt salts were obtained in the 2 to 15 micron region. Complexed ammonia shows four absorption bands, at approximately 3000, 1600, 1350, and 850 wave numbers. A possible assignment of three of these to N–H vibrations and the lowest to a rocking vibration, as proposed by Mizushima, is discussed. In the trisethylenediamine and hexanitrito complexes a frequency similar to the rocking vibration persists, but other frequencies characteristic of the particular ligands appear instead of N–H bands. A shift in the absorption maxima as the anions are changed shows that the fields of the anions are of importance. Fine structure observed in some of the strong absorption bands might be combinations with lattice vibrations.
A comparison of the absorption spectra of certain hexammines obtained from deposited pure powders and from pressed KBr plates shows differences in details, which may be interpreted as indicating dissociation of the cobalt salt in the pressed KBr plate and an essentially liquid structure for the latter.
The series of complex cobalt compounds whose infrared spectra were reported recently [D. G. Hill and A. F. Rosenberg, J. Chem. Phys. 22, 148 (1954)] has been extended to include a number of hexammines with various anions and several similar series of pentammines. A comparison has been made with a series of hexanitrito cobalt compounds and trisethylenediamine salts. The spectra of some of the compounds mentioned earlier have been remeasured and the range has been extended to the whole spectrum obtainable with a rocksalt prism. This has demonstrated greater complexity in the spectra than we had first imagined, but has led to a better understanding of them. Special care has been taken to insure the purity of all salts used.
Role of Nitric Oxide in the Thermal Decomposition of Nitrous Oxide
Authors: Kaufman Frederick , Gerri Norman J. , Bowman Roger E. 
Published: January 2005

The rates of decomposition of N2O and of formation of NO were measured simultaneously in a static system. NO yields at the beginning of reaction are as high as 50 to 60%, but NO quickly inhibits its own further formation. From initial NO yields, information about the reaction of oxygen atoms with N2O and about wall recombination was obtained. Limiting NO pressures for complete N2O decomposition were interpreted in terms of the reaction NO+O+M→NO2+M, and its rate constant was calculated. The effect of increased surface area and of added gases was studied. The halogens were found to be efficient inhibitors of NO formation.
The chemiluminescence of reacting N2O was observed and its dependence on temperature, pressure, and added gases studied. All evidence points to the reactionO+NO→NO2+hνas its origin. Inhibition of NO formation and of chemiluminescence is shown to be closely related.
Pyrolysis of Dimethyl Ether
Authors: Benson Sidney W. 
Published: January 2005

An analysis of the published data on the pyrolysis of dimethyl ether shows that the reaction can be interpreted as a chain decomposition initiated by CH3OCH3→CH3+OCH3, terminated by CH3 radical recombination and accelerated by the chain transfer reaction CH3+H2→CH4+H. A simplified Rice-Herzfeld mechanism then gives for the over-all rate of reaction the expression −d(Me2O)dt=k0(Me2O)12[1+β(CH2O)(Me2O)+α(H2)(Me2O)]where k0=k2(k1/k10)½; k2 representing H abstraction by CH3 from Me2O and k10, CH3 recombination.
The data yield a value of k0=4.31×10—3 (liter/mole)½ sec—1 at 777°K. Using published data on k2 and k10, an estimated activation energy E1=81.1 kcal and an estimated value of ΔS10=38 cal/mole-°K one finds A1=6.1×1016 sec—1 and for the reverse reaction to 1, A—1=7.0×109 liter/mole sec. The data do not permit evaluation of β while α is in the range 0.3 to 0.4 for both H2 and D2. Independent calculations of α yield the values 0.8 for H2 and 0.6 for D2, both calculations having a probable error of a factor of 2. For the over-all activation energy of the 32; order chain, E0=50.0 kcal.
It is proposed that the observed exchange of Me2O with D2 is a heterogeneous reaction.
Corresponding States Treatment of Nonelectrolyte Solutions
Authors: Scott Robert L. 
Published: January 2005

Recent theories of solutions (Prigogine and co-workers; Salsburg and Kirkwood) use a theory of corresponding states to deduce the properties of solutions from theoretically derived properties of the pure components (e.g., from the Lennard-Jones and Devonshire ``free volume'' or ``cell'' model). A characteristic of these theories is that they predict for molecules of the same size and dispersion force interactions a negative volume change on mixing.
Since the ``cell'' model gives very poor agreement with experimental data on energy-volume and volume-temperature relations of pure liquids, a corresponding states treatment has been carried through using an experimental equation of state for the pure liquid. If one assumes two kinds of ``cells'' in the mixture, a type for each of the components, the results agree with experimental data on solutions at least as well as previous theories. As before, contraction on mixing is found for a certain class of dispersion force solutions.
In any corresponding states treatment, the entropy of mixing will not be ideal either at constant pressure or at constant volume.
Dipole Moment of the HCN Molecule
Authors: Iguchi Kaoru 
Published: January 2005

π-electronic and σ-electronic energy levels of the HCN molecule are calculated by the LCAO method with full inclusion of configuration interaction.
Slater atomic orbitals with effective charge Z=3.180 for the carbon atom and 3.850 for the nitrogen atom are employed. The C–H distance is assumed to be 1.09 A and the C–N distance 1.15 A. The value 2.664 Debye units is obtained for the dipole moment of the molecule in the ground state, while the experimental value is 2.766 Debye units.
Improved Free-Volume Theory of Liquids. I
Authors: Dahler John S. , Hirschfelder Joseph O. , Thacher Henry C. 
Published: January 2005

To obtain practical results from the cell theories of liquids, it seems necessary to assume a simple symmetry for the distribution of a molecule about its lattice site. This is accomplished by replacing the interaction of the molecule with its neighbors by some ``suitably averaged'' interaction. In the Lennard-Jones and Devonshire treatment, the pair interaction is replaced by its spatial average. We find that a Boltzmann-type average is much more satisfactory. For an assumed symmetry of the distribution, our procedure provides an extension of Kirkwood's theory such that the resulting integral equation for the distribution function can be solved by numerical methods.
The introduction of the Boltzmann-type averaging provides a pair wise correlation between the motions of molecules in neighboring cells. These correlative effects have been neglected in previous cell theories of the liquid phase. Numerical calculations of the equation of state and thermodynamical properties are, at present, being carried out.
In evaluating the integrals which arise in this development, we have found the function L0 defined by the double surface integral ∫ ∫ f(r12,r1,r2,R)dω1dω2⧸ ∫ ∫ dω1dω2 =1R ∫ r12(min)r12(max)f(r12,r1,r2,R)L0(r1/R,r2/R,r12/R)dr12to be extremely useful. Here, r1 and r2 are the radii of two spheres, R the separation of their centers, r12 the separation of points on the two spheres, and f an arbitrary integrable function of r12/R. L0 is found to be a quadratic function of r12, different for various subranges of the interval [r12(max), r12(min)]. For a variety of physical problems such as x-ray and electron diffraction, L0 may have application.
Some Physical Properties of Pure Liquid Ozone and Ozone-Oxygen Mixtures
Authors: Jenkins A. C. , DiPaolo F. S. 
Published: January 2005

The melting point of pure liquid ozone has been determined by two methods and found to be —192.5±0.4°C. The surface tension of pure ozone at —182.7°C is 38.1±0.2 dynes/cm. Densities of pure liquid ozone are as follows: 1.5727±0.0004 g/cm3 at —182.9°C, 1.5839±0.0011 g/cm3 at —185.6°C, and 1.6130±0.0004 at —195.6°C, the last value being for the super-cooled liquid. The viscosity of pure liquid ozone is 1.56±0.2 centipoises at —183.0°C and 4.14±0.5 centipoises for the supercooled liquid at —195.6°C.
Densities of several liquid ozone-oxygen mixtures have been measured. These measurements show that densities of liquid mixtures can be calculated accurately from densities of pure oxygen and ozone by the relation 1/d = x1/d1+x2/d2, where d is the density of the mixture, d1 and d2 are the densities, and x1 and x2 the weight fractions of pure oxygen and pure ozone, respectively, at the given temperature.
Viscosities of ozone oxygen mixtures have been measured at —183.0°C and can be reproduced with an average deviation of 5% by the relation log10η=x1 log10η1+x2 log10η2, where η represents the viscosity of the mixture, η1 the viscosity of liquid oxygen, η2 the viscosity of liquid ozone, and x1 and x2 are the mole fractions of oxygen and ozone, respectively, all at the same temperature.
Dielectric Properties of Wool-Water Systems. II. 26 000 Megacycles
Authors: Windle J. J. , Shaw T. M. 
Published: January 2005

The complex dielectric constant for wool-water systems has been determined at a frequency of 26 000 Mc by a cavity resonator method similar to the method employed at 3000 and 9300 Mc. At 26 000 Mc, measurements on single wool fibers and at relative humidities as high as 98% have proved feasible.
The complex dielectric constant of the wool-water system increases with increasing water content. Curves for the dielectric constant and loss factor of the wool-water systems at 26 000 Mc are presented and analyzed in terms of a new theory of water sorption by wool. According to this theory, which is based upon a theory originally proposed by Cassie, the water sorbed by wool consists of three distinct molecular species: (1) localized water irrotationally bound to polar sites in the wool, (2) mobile water with bulk liquid properties, and (3) intermediate water with a potential energy of absorption which lies between those for localized and mobile water. The analysis of the measurements at 26 000 Mc for the higher relative humidities in terms of this theory has resulted in a more thorough description of the properties of the sorbed water than was possible for the data obtained at 3000 and 9300 Mc.
Scattering of High Velocity Neutral Particles. IX. Ne–A; A–Ne
Authors: Amdur I. , Mason E. A. 
Published: January 2005

Total collision cross sections have been measured for neon atoms with energies between 500 and 2100 ev, scattered in room temperature argon, and for argon atoms with the same energies scattered in room-temperature neon. The experimental results have been analyzed to obtain the following potential energy of interaction between a neon atom and an argon atom: V(r)=1.01×10−9/r9.18 erg,for r between 1.91 A and 2.44 A.
This potential is in agreement with one obtained by a simple combination of the potential between two neon atoms with that between two argon atoms. It is also consistent with the potential, valid at larger separation distances, which has been derived from measurements of gaseous compressibility, viscosity, and crystal properties.
Electronic Spectra of Polyacetylenes
Authors: Beer Michael 
Published: January 2005

The low-temperature emission spectra in rigid glass solutions of several substituted polyacetyelnes have been investigated. All the compounds phosphoresced with decay lifetimes ranging from 0.01 to 0.3 second. None of the compounds with less than four triple bonds fluoresced except diphenyl acetylene. All compounds with four triple bonds did fluoresce. An explanation is offered for this phenomenon. Some new absorption measurements were made on dimethyl diacetylene, dimethyl triacetylene, and dimethyl tetraacetylene. The polarization of the transition between 32 000 and 40 000 cm—1 in a single crystal of dimethyl triacetylene was found to be along the axis of the molecules. These results and those of previous investigators show that the energy level arrays of the molecules can be related and that they vary systematically as the number of triple bonds increases. This is in accord with expectation on the basis of simple molecular orbital theory.
An assignment of the symmetries of the electronic wave functions is proposed on the basis of the positions and intensities of the bands.
Electronic States and Potential Energy Diagram of the Iodine Molecule
Authors: Mathieson Lois , Rees A. L. G. 
Published: January 2005

The existing spectroscopic data on the iodine molecule have been reanalyzed, some new assignments proposed, and a potential energy diagram computed for some ten electronic states up to 55 000 cm−1. In particular, the following new assignments have been made for the upper levels of certain absorption bands—(1) a repulsive Σu+3(0u−) to the weak absorption at λ2700 in iodine vapor, (2) an ionic Σu−3(0u+) to the PRKM and Skorko band systems, and (3) a state arising from the mixing of a homopolar Π0+3(0u+u) and an ionic Σu+1(0u+) to the Cordes bands. In addition, the λ3416 and λ4300 ``continua'' have each been interpreted satisfactorily as a region of unresolved, overlapping bands with a lower limiting frequency. Other states lying in the region 40 000–55 000 cm−1 have been established.
New methods have been used to deduce segments of upper state potential energy curves.
Infrared Spectra of Polymers. I. Effect of Crystallinity on the Infrared Spectrum of Polyethylene and on the Infrared Spectra of Nylon 6 and Nylon 11
Authors: Tobin Marvin C. , Carrano Matthew J. 
Published: January 2005

The melt and polarization spectra of dotriacontane and polyethylene in the 750–1500 cm—1 region and of nylon 6 and nylon 11 in the 450–4000 cm—1 region are presented. In addition, the melt and crystal spectra of stearone are presented in the 650–3500 cm—1 region. The effect of crystallinity on the spectrum of polyethylene is discussed. With the aid of published Raman spectra of crystalline hydrocarbons, an assignment of frequencies for polyethylene is made. The effect of crystallization on the spectrum of stearone is discussed and unusual features pointed out.
Orientations in films of nylon 6 and nylon 11 are shown to be in the extrusion direction. The effect of melting on the hydrogen bonding and on the CO and NH frequencies is discussed. A partial assignment and classification of frequencies is made. When the films are melted, certain peaks vanish. These are ascribed to splitting arising from crystal forces.
Long-Range Intermolecular Forces
Authors: Dahler John S. , Hirschfelder Joseph O. 
Published: January 2005

The calculation of long-range intermolecular forces is systematized so as to apply to molecules in electronically excited states where resonance as well as electrostatic, induction and dispersion forces are encountered. Especial attention is given to deviations from the pairwise additivity of the energy of interaction of systems involving three or more molecules. Three types of nonadditivity are found. These are due to resonance degeneracy, molecular degeneracy, and multipole-induction effects. The following specific examples are considered: (a) the interaction energy of three hydrogen atoms, two in the ground state and the third in the first excited state; (b) the interaction of two polar, nondegenerate molecules with a hydrogen atom in its first excited state; and the multipole induction nonadditive interaction between (c) three polar molecules, and (d) three quadrupolar molecules.
Throughout these calculations the third and higher order terms in the perturbation are neglected.
Symmetries of Electric Fields About Ions in Solutions. Absorption and Fluorescence Spectra of Europic Chloride in Water, Methanol, and Ethanol
Authors: Sayre Edward V. , Miller Donald G. , Freed Simon 
Published: January 2005

The theoretical and experimental correlations between the symmetries of the microfields about ions, the degree of splitting of energy levels, and the selection rules for radiation have been so successful for ions in crystals that the extension of this approach to discover the precise point symmetries about ions in solutions appears limited only by instances where the spectra of the solutions are sufficiently discrete. The spectra of crystals containing a rare earth ion in known local symmetry furnish the quantum characters of the energy levels and then the numbers of lines in the respective transitions of the ions in solutions lead to the symmetries of the fields about the dissolved ions.
Salts of europium which are regarded as strong electrolytes exhibit sufficiently sharp absorption spectra in solutions at room temperature while their fluorescence spectra become adequately discrete at the temperature of dry ice. The absorption spectrum of europic chloride in water proved to be the same as in a mixture of water and alcohol. The latter solutions furnished the fluorescence spectra at the temperature of dry ice. Fluorescence spectra of the alcoholic solutions in the form of glasses were obtained at 77°K and 4°K.
The symmetry of the microfields about the europium ions in the anhydrous alcohols was C2v while that about the ions in aqueous solutions was D2h.
Photochemical Separation of Mercury Isotopes. I. A Study of the Emission and Absorption Hyperfine Lines of Mercury at 2537 A
Authors: Osborn K. R. , McDonald C. C. , Gunning H. E. 
Published: January 2005

An experimental and theoretical investigation has been made of the emission and absorption parameters in the excitation of Hg202 atoms in natural mercury to the 6(3P1) state by irradiation with the resonance line from an electrodeless discharge containing Hg202. The absorption has been studied as a function of (a) absorption path length, (b) the concentration of mercury in the absorption cell, (c) the pressure of certain foreign gases in the absorption cell, (d) the operating temperature of the lamp, and (e) the type of excitor used with the lamp.
The results of the study show that for the unique formation of Hg2026(3P1) atoms in natural mercury it is necessary to use a well-cooled source operating at the minimum power level consistent with steady radiation output. Furthermore, the pressure of foreign gas in the absorption cell must be kept low to eliminate Lorentz broadening effects on the absorption hyperfine line.
It has been found that the emission line from an electrodeless discharge operated at 26°C, and excited by a 2450 Mc oscillator, can be satisfactorily represented as a Doppler line modified by self-absorption. For the calculation of the frequency distribution of the emission line, the Doppler temperature of the emitting gas and the equilibrium temperature of the mercury in the lamp were taken as identical with the lamp wall temperature (26°C). The optical thickness of the path of self-absorption was evaluated from the dimensions of the lamp. It was found that the observed absorptions could be calculated directly from the ratio of the areas of the Doppler absorption line of the Hg202 atoms in the absorption cell to that of the self-absorbed emission line. The agreement between theory and experiment is taken as evidence that only Hg202 atoms are undergoing excitation under the defined conditions.
During the investigation the cross sections for Lorentz broadening of hydrogen, methyl chloride and isopropyl chloride were determined with respect to the Hg202 absorption line. The values found were respectively 53.1, 192, and 297×10—16 cm2.
This study was undertaken as a precursor to a systematic investigation of the reactions of various substrates with photo-excited mercury isotopes.
Lattice Entropies—Entropies of Vaporization of Ions from Crystals
Authors: Altshuller A. P. 
Published: January 2005

The entropies of vaporization of salts, the lattice entropies, have been calculated for salts containing both monatomic and polyatomic ions. The variations of the lattice entropies of these salts with valence type are discussed. The effects of ion size and ionic character on the lattice entropies also are considered.
The entropies of vaporization of single monatomic and polyatomic ions also have been computed. The effects of ion size, charge on the cation and anion, size of the central atom in oxy-anions, and the number of oxygen atoms attached to the central atom of the oxy-anions all are discussed.
The lattice entropies of monatomic salts should depend on the change from vibrational modes in the solid to translational modes in the gas. The lattice entropies of polyatomic salts depend in a complicated manner on the internal modes of motion in the gaseous polyatomic ions and in the solid.
Central-Field Approximation for the Electronic Wave Functions of Simple Molecules
Authors: Funabashi Koichi , Magee John L. 
Published: January 2005

The use of a central-field type of molecular orbital for the electronic wave functions of simple molecules has been investigated and application has been made to H2, H2O and CH4.
Ionization potentials calculated with the use of these wave functions are generally in good agreement with experimental values. No empirical data have been used in these calculations except the known equilibrium dimensions of the molecules. Interactions of all electrons are included. Configuration interaction, however, is not used.
Excitation potentials for H2O and CH4 are not in very good agreement with experimental values, which possibly means that configuration interaction cannot be neglected in such calculations.
Effects of Pressure on Ultrasonic Relaxation in Liquids
Authors: Litovitz T. A. , Carnevale E. H. , Kendall P. A. 
Published: January 2005

Measurements of sound absorption as a function of pressure in carbon disulfide and glycerol indicate that the relaxation effects causing the compressional losses in these liquids react differently to pressure changes. In CS2 the relaxation frequency increased with increasing pressure. In glycerol the relaxation frequency dropped as the pressure was increased. These results are consistent with the view that different relaxation mechanisms exist in associated and nonassociated liquids. The direction of the pressure changes in each case is in accord with the view that thermal relaxation is the cause of compressional loss in nonassociated liquids and that structural relaxation is the predominant factor in associated liquids.
A detailed study of the thermal relaxation effects in CS2 showed that the variations in relaxation frequency with pressure could not be adequately explained by Kittel's theory of thermal relaxation in liquids.
Theoretical considerations of the relaxational part of the specific heat indicated that it should be only slightly pressure dependent.
Potentiometric Titration, Association Phenomena, and Interaction of Neighboring Groups in Polyelectrolytes
Authors: Lifson Shneior 
Published: January 2005

The partition functions and potentiometric titration equations are calculated for a number of types of polyelectrolytes, including polyampholytes and other electrolytic copolymers. The effects of the interaction between neighboring groups and of the electrostatic potential of the macromolecule as a whole are both accounted for independently, by treating the ionized macromolecule as a separate phase in equilibrium with the surrounding solution.
The possibility of association of monovalent cations with the acidic groups of polyacids is discussed, following the derivation of the titration equations for both the H+ ion and the associating metallic cation.