bluuebunny/crossref_metadata_2025 huggingface dataset:
An Ultrasonic Investigation of a Chemical Kinetics Problem: The Dissociation of Magnesium Sulfate
Authors: Bies David Alan
Published: April 2005

New equations for the excess sound absorption per wavelength and the relaxation frequency have been derived. These equations are derived on the assumption that a dissociation process of the type (AB)⇌(A)+(B) is irreversibly perturbed by the sound field due to assumed pressure dependence of the equilibrium. These equations are applied to the problem of excess sound absorption in dilute magnesium sulfate solutions.

By using mixtures of dioxane and water to vary the dielectric constant of the solvent the effect of varying the ion Coulombic interaction forces of the ions in solution has been studied experimentally. This work and the work of other investigators on the excess sound absorption in dilute magnesium sulfate solutions is explained quantitatively.

The specific rates of dissociation and ion association for magnesium sulfate in solutions of water and water-dioxane have been determined. Good agreement is found between values of the mass action equilibrium constant determined by acoustic means and values determined by the usual conductivity method.

The experimental activation energy of molecular dissociation is determined to be 6.5 kcal/mole while the activation energy of ion association is estimated to be 8.5 kcal/mole.
Compressibilities of Ozone, Oxygen, and Ozone-Oxygen Mixtures and the Thermodynamic Quantities for Pure Ozone
Authors: Birdsall C. M. , Jenkins A. C. , DiPaolo F. S. , Beattie J. A. , Apt C. M.
Published: April 2005

The compressibilities of ozone and ozone-oxygen mixtures were calculated from recently determined critical constants for pure ozone, and from well-established data for oxygen. Data for pure ozone, pure oxygen, and mixtures containing 20, 40, 60, and 80 mole percent ozone are presented. The calculated compressibilities of pure ozone are used to correct thermodynamic quantities for the ideal gas, computed from spectroscopic data, to real gas conditions. Experimental determination of the compressibilities would be difficult because of the unstable nature of ozone.
Dielectric Constant of Polar Liquids at High Field Strengths
Authors: Booth F.
Published: April 2005

A critical examination is given of a simplifying assumption made in an earlier calculation of the functional dependence of the integral dielectric constant of polar liquids on the applied field. It was assumed in this calculation that, for the cavity and reaction fields at all field strengths the usual expressions for low field strengths could be employed. It was pointed out that this simplification is plausible if the static dielectric constant is large compared with the optical dielectric constant. In the present note it is shown that, if it is postulated that the reaction field alone retains its conventional value, then the cavity field is appreciably increased by dielectric saturation. In the case of water the effect is equivalent to an increase of the external field by about 10 percent; a modified relation between the field and the dielectric constant is suggested.

The alteration of the reaction field as a result of saturation, and the effect of this modification on the dielectric constant, are also examined.
Molecular Formulation of Thermodynamic Functions Encountered in Solution Theory
Authors: Buff Frank P. , Brout Robert
Published: April 2005

The general statistical mechanical formulation of partial molar energies, ``internal pressure,'' and heat capacity of multicomponent systems is developed with use of the grand ensemble. In the case of two component systems, detailed concentration expansions are presented for partial molar free energies and energies and for radial distribution functions about standard states at constant temperature and pressure as well as constant temperature and partial molar volume.
Effect of Variations in Source Intensity on the Alpha-Induced Decomposition of Ammonia
Authors: Burtt Benjamin P. , Baurer Theodore
Published: April 2005

The ion yield in the alpha-induced decomposition of gaseous ammonia is found to increase slightly with the irradiation intensity, both in the presence and absence of electric fields. This is true for ammonia pressures of both 20 cm and 50 cm, at room temperature. Even a weak electric field increases the ion yield at 50 cm pressure. There is no evidence at 20 or 50 cm pressure of initiation of the reaction by ion recombination. Possible mechanisms are suggested.
Fine Structure of the 2.7 Micron Carbon Dioxide Rotation-Vibration Band
Authors: France W. L. , Dickey F. P.
Published: April 2005

The infrared spectrum of CO2 in the region of 2.7μ has been remeasured. Five rotation-vibration bands have been identified and analyzed in detail. One of these is due to C13O2. The rotational constants obtained were B000=0.3904 cm−1 and D000=0.25×10−6 cm−1.In two of the bands l-type doubling occurs, and the values of the splitting constants q were determined.
Mass Spectrum of Lithium Iodide
Authors: Friedman Lewis
Published: April 2005

The mass spectrum of lithium-iodide vapor produced from salt heated in an oven in the ion source of an analytical mass spectrometer was investigated as a function of oven temperature. Evidence was obtained for the existence in the vapor of both monomer and dimer. Partial heats of sublimation to monomer and dimer at 0°K were found to be 44.9±0.7 and 45.5±2 kcal respectively. The heat of dissociation of (LiI)2 into gaseous monomers was found to be 44.4±2.2 kcal. The partial heat of sublimation of monomer was used with supplementary thermochemical data to obtain values for the lattice energy and the heat of dissociation of the diatomic molecule.

Appearance potentials for the major ions in the spectrum where determined. Upper limits for the energy of dissociation of the gaseous diatomic molecule were derived from the appearance potentials of Li+ and I+ which were slightly higher than the thermochemical value.
Infrared Intensities and Bond Moments in Formaldehyde
Authors: Hisatsune I. C. , Eggers D. F.
Published: April 2005

The infrared band intensities of formaldehyde have been measured in the gas phase using the pressure broadening method. From the results of the normal coordinate analysis and the experimental intensities, the bond moments and their derivatives have been calculated for the three symmetry species. The relative signs of ∂μ/∂Q5 and ∂μ/∂Q6 have been determined from the investigation of the Coriolis interaction between ν5 and ν6. The results chosen from the calculations are: μCH = 0.5D (C——H+), (∂μ/∂r)CH = 1.3×10—10 esu, μCO = 1.9D (C+—O—), (∂μ/∂r)CO = —1.9×10—10 esu. The B1 symmetry block gave an abnormally large μCH of about 1D.
On the Analysis of Dielectric Relaxation Measurements
Authors: Cole Robert H.
Published: April 2005

Convenient methods of analyzing dielectric dispersion and loss data satisfying the Debye equations are described and illustrated. The similarities and differences of the Fuoss-Kirkwood and circular arc representations of symmetrical, non-Debye-type dispersions are considered. Interpretations given by various writers to the asymmetric dispersion found by D. W. Davidson and the writer for glycols are discussed. Finally, the possibilities and limitations of reduced representations of dielectric measurements are examined
Self-Diffusion Coefficient and Viscosity in Liquids
Authors: Li James C. M. , Chang Pin
Published: April 2005

The relation between self-diffusion coefficient and viscosity is examined in terms of the early hydrodynamic theory and Eyring's kinetic theory. They differ by a factor of about 6. A detailed consideration of the kinetic theory shows that this factor should have been included in Eyring's derivation of viscosity if a proper meaning is given to the relative velocity involved.
Decomposition of Ammonia Photosensitized by Mercury 6(3P1) Atoms
Authors: McDonald C. C. , Gunning H. E.
Published: April 2005

An investigation has been made of the mercury—6(3P1)—photosensitized decomposition of ammonia at room temperature, under both flow and static conditions. Nitrogen and hydrogen were produced in the static experiments; hydrazine was an additional product in the flow experiments.

The quantum yield of ammonia decomposition in the flow experiments did not depend on the flow rate but increased in an exponential manner, as the reaction pressure was decreased, from a value of 0.09 at 650 mm toward unity at very low pressures. The quantum yield in the static experiments at high ammonia pressures and at a low extent of reaction was about the same as in the flow experiments at comparable pressures. The static quantum yield decreased when the extent of reaction was increased, when the ammonia pressure was decreased, or when hydrogen was added to the reaction.

The percentage of the decomposed ammonia which was recovered as hydrazine increased from zero at low flow rates to 95 percent at high flow rates. At a fixed flow rate, the hydrazine-to-nitrogen ratio increased, as the ammonia pressure was increased, from zero to a maximum value which was pressure independent at higher pressures. The hydrazine-to-nitrogen ratio increased as the incident intensity of 2537 A radiation was decreased. When ethylene was added to the flow experiments the hydrazine-to-nitrogen ratio was markedly increased. However, when platinum wire was introduced into the irradiated zone, the reaction was found to be unchanged.

A mechanism is suggested which appears to give the best representation of the results.
Asymmetric Rotor. XII. The Infrared Spectrum of Hydrogen Sulfide from 7480 to 7880 cm—1
Authors: Ordway Girard L. , Cross Paul C. , Bair Edward J.
Published: April 2005

About two hundred lines have been observed in the spectrum of hydrogen sulfide between 7480 and 7880 cm—1. The absorption has been analyzed as due to three levels of the interacting Darling-Dennison pairs (v1v2v3) = (201) (003) and (102) (300). The constants obtained were for (201)ν0=7576.3, A′=9.97, B′=8.54, C′=4.55 cm—1; for (300)ν0=7751.9, A′=10.08, B′=8.52, C′=4.54 cm—1; and for (003), ν=7779.2, A′=9.80, B′=8.68, C′=4.57 cm—1. The (102) band, expected to be very weak, may be coincident with the (201) band and have approximately the same constants.
An SCF LCAO MO Study of N2
Authors: Scherr Charles W.
Published: April 2005

The self-consistent-field molecular-orbital method in the LCAO (linear combination of atomic orbitals) approximation is applied to the ground-state configuration of the nitrogen molecule at the observed equilibrium internuclear separation. No other approximations are used; all electrons are included. The forms of the resulting molecular orbitals are discussed. The s-p hybridization is computed to be 26.1 percent in agreement with Mulliken's magic formula estimation of 21 percent. The quadrupole moment is computed to be —1.87 a.u. (experiment, 1.11 a.u. of undetermined sign). The ratio of the computed to the experimental total molecular energy is found to be 0.9905. Ionization potentials and single-electron excitation energies are computed and compared with experimental spectroscopic values. The spectral results are more encouraging than have been hitherto reported from calculations by the LCAO molecular-orbital method. The approximation of neglecting the inner-outer-shell mixing, as it has usually been done in computations of this type, somewhat changes the present results and is not recommended.
Correlations between Characteristic Frequencies of the Paraffins and the Skeletal Frequencies of Some Structurally Analogous Polar Molecules
Authors: Sheppard N. , Simpson D. M. , Agar J. N.
Published: April 2005

Some close analogies are found in the region 1500 to 600 cm—1 between the frequencies of a number of paraffins and their more polar analogs in which CH3 groups are replaced by F, OH, or NH2 groups. The great intensities of the infrared bands of the polar molecules have led to their assignment to skeletal stretching modes; a similar assignment for the frequencies of the paraffins may therefore be deduced. On this criterion the 1053 cm—1 band of propane, the 1170 cm—1 band of isobutane, and the 1249 cm—1 band of neopentane are to be attributed principally to skeletal stretching vibrations. Some apparently contradictory conclusions reached earlier from studies of deuterium substituted propanes and neopentanes are discussed.
Theory of Protein Solutions. I
Authors: Hill Terrell L.
Published: April 2005

A summary of a few results of the McMillan-Mayer solution theory is given in Sec. II, in order to have available necessary equations in a form required in later sections. It is pointed out in Sec. III that binding equilibria in a solution can in principle be discussed equally rigorously either implicitly or explicitly. The definition of ``binding'' in an explicit formulation is, strictly speaking, somewhat arbitrary but the arbitrariness disappears for practical purposes if the binding forces are very strong. However, the purely thermodynamic results are rigorously independent of the exact definition used. With the aid of Secs. II and III, it is possible to formulate in Sec. IV a general theory of protein solutions, including the effect of binding of ions or molecules on protein molecules. The discussion here is restricted to a single protein species and a single type of molecule capable of being bound, but the generalization to any number of protein or bound species is easy and will be published later. The topics discussed are osmotic pressure virial expansion, number of bound molecules per protein molecule expanded in powers of the protein concentration, distribution functions for sets of protein molecules (including the radial distribution function), potentials of average force on sets of protein molecules, superposition approximation in relation to the osmotic pressure and the Born-Green-Yvon integrodifferential equation for the distribution functions, and, finally, the relation to the recent Kirkwood—Shumaker theory. The theory applies equally well to polyelectrolyte, colloidal, and other solutions, but the ``protein'' language is used throughout for definiteness.
Note on an Analytical Proof of Wulff's Theorem in Three Dimensions
Authors: Benson G. C. , Patterson D.
Published: April 2005

A proof of Wulff's theorem for the equilibrium shape of a two-dimensional crystal has been given by Burton, Cabrera, and Frank. This has been extended to three dimensions in the present note and an expression has been derived for the principal radii of curvature of the crystal.
Acid Catalysis in the Thermal Decomposition of Ammonium Nitrate
Authors: Wood Bernard J. , Wise Henry
Published: April 2005

Experimental measurements of the kinetics of thermal decomposition of ammonium nitrate have been made in the temperature range from 443 to 553°K. The results indicate that the degradation of ammonium nitrate is an autocatalytic liquid-phase reaction, the rate of which is proportional to the product of the mass of salt and the concentration of acid. The activation energy for this process is found to be 31.4 kcal. Adjustment of the concentration of acid present offers an effective means for the control of the rate of thermal degradation of ammonium nitrate.
On the Helical Configuration of a Polymer Chain
Authors: Shimanouchi Takehiko , Mizushima San-ichiro
Published: April 2005

A mathematical expression for the helical configuration of a polymer chain has been derived as a function of the bond lengths, bond angles, and internal rotation angles. The result of the calculation has been applied to the determination of stable configurations of several polymer chains.
Production of Excited Hydroxyl Radicals in the Hydrogen Atom-Ozone Reaction
Authors: McKinley J. D. , Garvin David , Boudart M. J.
Published: April 2005

Near-infrared emission spectrograms of vibrationally excited hydroxyl radicals in the ground state have been obtained upon mixing H atoms and ozone. A recent interpretation of a particular source of the night-sky radiation has been verified. A nonequilibrium distribution of energy between the reaction products is indicated.
Analysis of the Near Ultraviolet Absorption Spectra of ortho- and para-Dichlorobenzene Vapors
Authors: Anno Tosinobu , Matubara Ikuo
Published: April 2005

The absorption spectra of o- and p-dichlorobenzene vapors appearing in the region 2900—2400 A and 2950—2400 A, respectively, were photographed and measured. For the ortho-spectrum the band at 36 232 cm—1 is assigned as the 0—0 band. The progression with frequency intervals of 1089 cm—1 starts from the stronger bands. For the para-spectrum, the band at 35 750 cm—1 is taken to be the 0—0 band. The only progression-forming frequency is 1051 cm—1. In both the spectra, most of the prominent bands are assigned to progressions or combinations of the possible fundamental frequencies. The fundamental frequencies are compared with the Raman values. From the vibrational analysis it is concluded that both molecules in the excited electronic states retain all their elements of symmetry in the ground states. For the para-compound the molecular structure in the upper state is discussed in some detail.
Nuclear Magnetic Resonance in Concentrated Aqueous Electrolytes
Authors: Shoolery James N. , Alder Berni J.
Published: April 2005

The proton magnetic resonance of water has been examined in the presence of various concentrations of different diamagnetic salts. The observed shifts of the resonance frequency relative to that of pure water are interpreted in terms of the breakdown of the hydrogen-bonded structure of water and the ability of the ions to polarize the water molecules. The concentration dependence of the shifts for the multivalent electrolytes indicates cation-anion interactions at higher concentrations. The quite narrow single line observed for all but the Al+++, Be++, and the very concentrated ZnCl2 solutions shows that in most cases the proton exchanges faster than 104 times per second. The magnetic field dependence of the line width in the AlCl3 solution indicates that a rate of exchange of the proton of about 102 times per second is responsible for the broadening, while in the ZnCl2 and BeCl2 solutions the high viscosity appears mainly to be responsible for the increased line width. The fluorine magnetic resonance studied at several concentrations in KF solutions provides further information about the solvent-ion interaction.
Reactions of Hg (3P1) with Toluene
Authors: Sehon A. H. , Darwent B. deB.
Published: April 2005

The reactions between Hg(3P1) and toluene have been investigated between 150° and 400°C at pressures from 0.4 to 30.5 mm Hg. The gaseous products are H2, CH4, and C2H6. The quantum yield for H2 is 5×10—4 at 150°C and increases to about 10—1 at 400°C. A mechanism based on two types of excited toluene molecules is proposed.
Reactions of Nitrogen Activated by Electric Discharge
Authors: Varney R. N.
Published: April 2005

For gaseous reactions of nitrogen with hydrogen or with oxygen, it was necessary to pass only the nitrogen through a glow discharge, the other gas being admitted at a later point in the flow line. Ammonia, nitrous oxide, and dinitrogen trioxide were formed, respectively. By suitable control of fields it was established that nitrogen ions were playing no direct role in the reactions but rather a neutral form of activated nitrogen in every case. Passing the hydrogen or oxygen alone through the discharge and then admixing nitrogen yielded no reaction product at all. Several further results indicated that ionic processes on the whole are not active in gas discharge reactions.
Vacuum Photolysis of Silver Bromide and Silver Chloride
Authors: Luckey George W.
Published: April 2005

The quantum yields of halogen production in the vacuum photolysis of silver bromide and silver chloride have been measured at various temperatures, wavelengths, and light intensities. Silver-bromide crystals containing small amounts of copper and cadmium bromide have also been studied. At room temperature, the yields of thick crystals follow the equation, φ=Q(1−e−ka),where Q is the surface efficiency, k is the absorption coefficient, and a is a parameter which is defined below. At room temperature, in the halogen evolution range studied, the value of a for silver bromide is about 0.4 micron and that for silver chloride is about 0.24 micron. The values of Q are usually between 0.5 and 1.0.

The quantum yield of halogen production at room temperature is similar to the yield of a fast wall reaction. Both depend on the diffusion of reactants to the surface. The parameter a is related to the thickness of the diffusion layer. A numerical solution of the diffusion equation by C. A. Duboc has shown that a=1.154D12k14k114Io14,where D is the diffusion coefficient of positive holes and electrons, k1 is the recombination coefficient of positive holes and electrons in the silver halide, and Io is the incident intensity of light.

Above a certain temperature, the quantum yields decrease with increasing temperature, the long-wavelength yields increase relative to those at short wavelength and the yields increase with increasing light intensity. These effects are inhibited by the addition of copper bromide to silver-bromide crystals. The decrease in yield at high temperatures is probably caused by the decreased effectiveness of traps. The cadmium results indicate that this decrease is also affected by the ionic conductivity of the crystals. The addition of copper or cadmium ion does not have a large effect on the quantum yields at room temperature. This indicates that positive-ion vacancies in the silver halides are not good positive hole-traps at room temperature. The data and the solution of the diffusion equation indicate that the quantum yield of photoconductivity and photolysis are closely related. Additional measurements of photoconductivity and light-absorption coefficients are needed before the results can be completely interpreted.
Selection Rules for Normal Modes of Chain Molecules
Authors: Tobin Marvin C.
Published: April 2005

The selection rules for chain molecules are derived on the basis of the theory of one-dimensional space groups. The selection rules for crystals of polymer chains are discussed and correlated with those of isolated chains. The polyethylene molecule is analyzed in detail by these methods and the predictions of the theory compared with experiment. The effects of perturbations on the spectra are discussed.
Infrared Intensity of the C — D Stretch of Chloroform-d in Various Solvents
Authors: Huggins Charles M. , Pimentel George C.
Published: April 2005

Infrared measurements of the frequency and intensity of the C — D stretching and bending motions of CDCl3 in various solvents are presented. The expected relationship between heat of solution and lowered stretching frequency is shown not to extend to CDCl3. There is, however, a correlation between apparent integrated intensity of this band and the extent of interaction in the same solvent. The band is over thirty times as intense in triethylamine as in carbon tetrachloride solution. No large change in the intensity of the bending motion was observed. The infrared spectral properties of chloroform-d are interpreted to indicate molecular interactions similar to hydrogen bonding interactions.
Method of Integrating the Rate Equations for Free Radical Initiated Polymerizations
Authors: Howe John P.
Published: April 2005

A method is given for integrating the equations for the rate of polymerization reactions without the assumption of steady states for the concentrations of the various free radicals. The main reaction steps used are: free radical production, chain propagation, chain transfer, and chain termination. Explicit expressions are found for the total amount of polymer, the number average, and the weight average as a function of time for the particular case of free radicals produced initially by a pulse of light. Other modes of dependence on time for the primary free radicals may also be treated.
Decomposition of Carbon Dioxide by Ionizing Radiation. Part I
Authors: Harteck P. , Dondes S.
Published: April 2005

The irradiation of gaseous carbon dioxide with radon or in a nuclear reactor, produces about 0.1 percent decomposition of primarily dissociated carbon dioxide, correlating with previous results in the literature. The irradiation of solid carbon dioxide with radon produces carbon monoxide and oxygen with a G value of 9 to 10. The irradiation of gaseous carbon dioxide, containing a small amount of nitrogen dioxide, by radon or in a nuclear reactor, produced carbon monoxide and oxygen, with a G value of 9 to 10. Percentages as small as 0.5 percent of nitrogen dioxide are sufficient to stop the back reaction to carbon dioxide. A new mechanism has therefore been proposed for the ineffectual decomposition of carbon dioxide by ionizing radiation, and the effective decomposition when nitrogen dioxide is present. With the proposed mechanisms, the classical experiments of Lind, the carbon monoxide oxidation and the carbon monoxide decomposition, are quantitatively explained.
Statistical Computation of Mean Dimensions of Macromolecules. II
Authors: Wall F. T. , Hiller L. A. , Atchison W. F.
Published: April 2005

Random walks subject to the excluded volume effect have been generated by means of a high-speed electronic digital computer for four different two-dimensional lattices. A semiempirical theory has also been developed for interpreting the statistical data. From the results obtained it is possible to show for several two-dimensional lattices that the quotient, 〈rn2〉Av/n, diverges as n→ ∞, where 〈rn2〉Av is the mean square length of permissible walks of n steps. This conclusion was reached by using an appropriate difference equation in conjunction with data on the mean square lengths of successful walks and the mean square lengths of failures resulting from ring closures. Integration of that difference equation indicates that if n is sufficiently large, 〈rn2〉Av is proportional to nA, where A depends upon the lattice system.
Effect of a High cis-Barrier on the Microwave Spectrum of Hydrogen Peroxide
Authors: Massey J. T. , Hart Robert W.
Published: April 2005

The frequency spectrum in the microwave region and the Stark effect are obtained for the case of a potential function with a high cis-peak and a low trans-peak. Using the presently available experimental data on H2O2 it is not possible to determine whether this potential function or the cis-peak equal trans-peak potential function is correct. It is shown, however, that the microwave data can answer this question if sufficient resolution is obtained.
Infrared Spectrum, X-Ray Diffraction Pattern, and Structure of Ammonium Fluoride
Authors: Plumb Robert C. , Hornig Donald F.
Published: April 2005

The infrared spectrum of ammonium fluoride and deutero-ammonium fluoride at —195°C and 25°C is shown to be explicable in terms of ``essentially'' Td symmetry requiring that the axial ratio (c/a) be 1.63. New x-ray-lattice parameter measurements show this to be true. A comparison of the spectrum of NH4F with other ammonium salts indicates that broad bands do not necessarily accompany strong hydrogen bonds.
Spectra of Transition-Metal Complexes
Authors: Orgel L. E.
Published: April 2005

The electronic transitions observed in complexes of the transition-metal ions are interpreted in terms of a slightly modified crystal-field theory. Parameters of chemical interest are derived.
Studies of the Interaction between Stable Molecules and Atoms. III. A Molecular Orbital Treatment of the Quadratic Form of H4
Authors: Griffing Virginia , Maček Andrej
Published: April 2005

Molecular orbital calculations of the quadratic arrangement of four hydrogen atoms have been carried out as a function of the internuclear distance. It is shown that the complex has orbital degeneracy in the ground state. An approximation, which includes the lowest orbital and the degenerate orbitals only, yields a triplet and three singlet states, the triplet being the lowest one in accordance with Hund's rule. The actual calculations show that the quadratic H4 is unstable with respect to a totally symmetrical displacement at all points of the potential energy surface.
Infrared Absorption Spectra of Monodeuterated Pyridines
Authors: Andersen F. Allan , Bak Bo/rge , Brodersen Svend , Rastrup-Andersen John
Published: April 2005

For this work 2D-, 3D-, and 4D-pyridine have been prepared from corresponding halogen compounds. The infrared spectra of the compounds in the liquid phase are reported over the spectral range 400—3200 cm—1. Interpretation of the spectra is carried through by analogy with the spectra of isotopic benzenes, pyridine, and pyridine-d5.
Theory of Normal Paraffin Liquids
Authors: Kurata Michio , Isida Sin-iti
Published: April 2005

A hole theory of n-paraffin liquids, which is the same in mathematical form as Flory's theory of polymer solutions, is developed to derive the relationships between the physical constants and the number of carbon atoms n. If the number of segments in a molecule is equal to n⅔, quantitative agreements between the theory and the observations can be shown for the critical temperature, the critical pressure, the boiling temperature and the heat of vaporization. It is also possible to give theoretical foundations for some empirical rules recently proposed by Grunberg and Varshni.
Statistical Mechanics of Polymer Solutions. Parts I and II
Authors: Kurata Michio , Tamura Mikio , Watari Tatsuro
Published: April 2005

Some contributions are made to the refining of the lattice model theory of Flory of chain polymer solutions by introducing the idea used in the recent theory of regular assembly that combinatory factor constructed in terms of multiple site clusters can be properly used to take long-range correlations between a given site and its far distant neighbors into account.

In Part I, the combinatory factors of Flory and others in current use are reconstructed to exemplify the pseudo-assembly method which has been presented by Kikuchi and the present authors for an easy construction of combinatory factors of higher-order approximation for regular assembly, and to give a thorough understanding of the succeeding uses in Part II.

In Part II, a refined theory of chain polymer solutions is developed. The final expressions for the entropy of dilution and the osmotic pressure depend on the flexibility and the degree of branching of the polymer chain, and give a better agreement with observed data even at high dilution.
Mercury Photosensitized Decomposition of Nitrous Oxide
Authors: Cvetanović R. J.
Published: April 2005

The reaction of nitrous oxide with Hg(3P1) atoms at 23°C has been investigated. The evidence obtained indicates that the sole primary process is a splitting of the nitrous oxide molecule into a nitrogen molecule and an oxygen atom. The possible secondary reactions are discussed.
Contribution to the Theory of Fast Reaction Rates
Authors: De Vogelaere R. , Boudart M.
Published: April 2005

Classical calculations of the motion of a mass point on a potential surface are carried out. The surface corresponds to a reaction of the type AB+A=A+BA and is characterized by a single saddle-point. With reference to the mathematically similar problem of the allowed cone of cosmic radiation, a novel feature of fast chemical kinetics is described: the possibility of a substantial decrease of the transmission coefficient above a certain critical energy of the system. This result does not depend on the analytical expression of the surface chosen in the present work. The generality and some consequences of this phenomenon are discussed.
Proton Magnetic Resonance Studies of Chloroform in Solution: Evidence for Hydrogen Bonding
Authors: Huggins Charles M. , Pimentel George C. , Shoolery James N.
Published: April 2005

The concentration and temperature dependences of proton magnetic resonance measurements on chloroform in acetone and triethylamine solutions are presented. The behavior is similar to hydrogen bonding systems and it is concluded that there is a specific interaction involving the chloroform proton and the solvent molecule. In each system the data are consistent with the assumption of a one-to-one complex. Equilibrium constants and heats of formation are calculated.
Infrared Spectra of Gaseous and Solid Hydrazoic Acid and Deutero-Hydrazoic Acid: The Thermodynamic Properties of HN3
Authors: Dows David A. , Pimentel George C.
Published: April 2005

Infrared studies of HN3 and DN3 in the gas and solid phases and of HN3 in CCl4 solutions are presented. The two low-frequency skeletal bending modes are identified, permitting calculation of the thermodynamic properties of hydrazoic acid. Hydrogen bonding of HN3 and DN3 in the solid state is indicated by frequency shifts of the NH and ND stretching motions (216 and 151 cm—1, respectively). No evidence of hydrogen bonding was observed in solutions of HN3 in CCl4 at concentrations up to 0.3 M. An irreversible phase transition is observed on warming solid hydrazoic acid above about 120°K.
Ion Pair Yields in the X-Ray Decomposition of Hydrogen Bromide in Rare Gas Atmospheres
Authors: Zubler Edward G. , Hamill William H. , Williams Russell R.
Published: April 2005

The rate of x-ray induced decomposition of hydrogen bromide has been measured both in the pure gas and in rare gas atmospheres. The rate of ion pair formation under identical irradiation has been determined from the saturation ionization currents in rare gases and ion pair yields for decomposition of hydrogen bromide have been computed. Average yields were A–HBr, 4.7; Kr–HBr, 4.0; Xe–HBr, 4.7; HBr, 4.6; HBr–Xe, 5.2; where the first substance named is the major component. A mechanism for decomposition by ion formation accounts for a yield of 4.0. Values above this are attributed to dissociative excitation without ionization.
Measurement of the Chapman-Jouguet Pressure and Reaction Zone Length in a Detonating High Explosive
Authors: Duff Russell E. , Houston Edwin
Published: April 2005

The Chapman-Jouguet pressure and the reaction zone length in detonating Composition B containing 63 percent RDX at a density of 1.67 g/cc have been measured by determining the initial free surface velocity imparted to aluminum plates as a function of plate thickness. The C-J pressure is 0.272 megabar and the reaction zone length is 0.13 mm. The experimental free surface velocity-plate thickness curve provides powerful confirmation for the pressure profile in a detonating explosive predicted by the hydrodynamic theory of detonation proposed by Zeldovich, von Neumann, and Doring.
Effect of Isotopic Substitution on the Mass Spectra of Molecules. II. Oxygen and Carbon Dioxide, Experimental
Authors: Schaeffer Oliver A. , Owen Henry R.
Published: April 2005

The relative changes in the probability of bond breaking following electron impact have been studied for the molecules O16O16 and O16O18; O16C12O16, O16C13O16, and O16C12O18. The experimental results were obtained with a 60° mass spectrometer employing a source designed to equalize the collection efficiency of the fragment ions formed. The relative changes were studied systematically as a function of the various ion source voltages. In the case of oxygen the ratio of bond breaking in O16O18 divided by that in O16O16 is 0.98. The formation of C+ from O16C13O16 is 1.022 times the formation of C+ from O16C12O16 while the formation of C+ from O16C12O18 is 0.997 times the formation of C+ from O16C12O16. The formation of CO+ from O16C13O16 is 0.974 times that from O16C12O16 while the relative formation of C12O18+ from O16C12O18 is 1.03 times and that of C12O16+ is 0.97 times the formation of CO+ from O16C12O16. Finally the relative formation of O16+ is 1.05 times and that of O18+ is 0.98 times the formation of O+ from O16C12O16. The values for O16C13O16 are compared to previous values in the literature.
Infrared Spectrum of SOF2
Authors: O'Loane J. Kenneth , Wilson M. Kent
Published: April 2005

An investigation of the infrared spectrum of gaseous thionyl fluoride results in the following fundamental assignment: ν1(a′)=1333 cm−1,  ν2(a′)=808 cm−1,  ν3(a′)=530 cm−1.ν4(a′)=(410) cm−1,  ν5(a′′)=748 cm−1,  ν6(a′′)=390 cm−1.

Thermodynamic functions for SOF2 are calculated with the usual assumptions.
Raman Spectra of Thionyl Fluoride and Sulfuryl Fluoride
Authors: Bender Paul , Wood James M.
Published: April 2005

The Raman spectra of liquid and gaseous sulfuryl fluoride (SO2F2) and of liquid thionyl fluoride (SOF2) have been investigated and depolization factors measured for the stronger lines scattered by the liquids. For SO2F2 the Raman shift due to the infrared inactive torsional mode has been found to be 388 cm—1, and other previous assignments based on the infrared spectrum have been confirmed. For SOF2, the symmetric SF2 stretch occurs at a higher frequency than the asymmetric stretch; the reverse is true for SO2F2. The symmetric SF2 bending mode has escaped detection for both compounds.
Concentration of Nitrogen-15 by Chemical Exchange in a Thermal Diffusion Column
Authors: Spindel W. , Taylor T. I.
Published: April 2005

A concentration of nitrogen-15 has been effected in a thermal diffusion column under conditions where the gaseous exchange action, N14O2+N15O⇄N15O2+N14O, can contribute to the separative process. The top of the column is fed with NO2 of normal isotopic abundance. Reversible thermal decomposition of NO2 into NO and O2 establishes a radial concentration gradient so that the descending cold stream is predominantly NO2 and the inner hot ascending stream is largely NO and O2. As a result of the exchange reaction, N15 preferentially concentrates in the NO2 and is carried to the bottom of the column. Here the enriched NO2 re-enters the hot rising stream and is again decomposed into NO which undergoes further exchange. This reversible thermal decomposition makes it possible to operate the column without a chemical converter as was needed in the CO–CO2 system.

The over-all isotope separation has been studied in a two-meter column as a function of pressure (0.25 to 1.0 atmosphere), temperature (400 to 700°C) and withdrawal rate (5 to 66 cc atmospheres per day). A maximum over-all separation of 2.6 was obtained at a filament temperature of 685°C and a pressure of 0.5 atmosphere. At a withdrawal rate of 27 cc atmospheres the over-all separation is about 70 percent of this maximum value.

The system is a rather complicated one, and it is not yet possible to completely evaluate the contribution of each separative process that can occur in the column.
On the Adsorption of Oxygen on Tungsten as Revealed in the Field Emission Electron Microscope
Authors: Becker J. A. , Brandes R. G.
Published: April 2005

The tungsten surface in a field emission microscope is exposed to oxygen gas at a pressure near 5×10—8 mm and the effect of the gas on the field emission is observed. During the first 30 seconds, the emission decreases rapidly, but some regions deactivate more rapidly than others. During the next 12 minutes, the rate of deactivation is much slower, but again the change in activity for some planes is much more pronounced than for others. After the surface is heavily covered, the oxygen is desorbed by glowing the tungsten for one minute at successively higher temperatures.

The chief conclusions are: Oxygen is adsorbed on tungsten in three stages or layers. In the first layer, the bond strength is about 5 electron volts and the oxygen cannot be removed below about 1500°K. In the second layer, the bond strength is about 2.5 ev and the oxygen cannot be removed below about 750°K. These bond strengths depend somewhat on the crystallographic plane. In the third layer, the oxygen forms a variety of molecular complexes with the substrate. These reveal themselves as intensely bright, highly localized groups of spots. Each spot is due to electrons emitted by individual atoms in a molecule. The conditions necessary to observe such adatoms are given.
Quenching of NaI Fluorescence by H2, HCl, CO2, and H2O
Authors: Hanson Howard G.
Published: April 2005

The experimental quenching cross sections of H2, HCl, CO2, and H2O for the sodium D lines arising from the optical dissociation of the sodium iodide molecule have been determined by measurements with a photomultiplier tube. The velocities of the excited sodium atoms after dissociation of the sodium iodide molecules by ultraviolet light of different wavelengths have been determined by using an approximation for the repulsive potential curve of an excited sodium atom and normal iodine atom obtained from a measurement of the excitation of the sodium D lines as a function of exciting ultraviolet wavelength. The variation of quenching cross section for HCl and CO2 with relative velocities of excited sodium atom and quenching molecules shows a decrease of cross section with increase in relative velocity. The cross section for H2 shows little change with relative velocity in the range of velocities used. H2O shows little quenching action. The source of ultraviolet light was a hydrogen discharge lamp and the wavelength of the exciting ultraviolet light in the 2100 A—2500 A range was controlled by a reflection grating monochromator.
Shape of the Consolute Curve and its Consequences for the Theory of Binary Liquid Mixtures of Nonelectrolytes
Authors: Kohler F.
Published: April 2005

The experimental results on the shape of the consolute curve of binary liquid mixtures with components A and B, especially the cubic dependence of the concentration on temperature, imply certain peculiarities in the behavior of the excess free energy of mixing ΔGexc. The term ΔGexc is expressed as W · x(1 — x) ·Ψ (x). Here 2W can be considered as the change in free energy, times Avogadro's number, when z contacts A—A and z contacts B—B are changed into 2z contacts A—B; x is the molefraction of one component, and z the coordination number. Moreover, Ψ(x) is much more sensitive than ΔGexc, and has a theoretical significance, being proportional to the ratio of the number of A—B contacts in the system investigated to their number in a perfect solution if the assumptions of the strictly regular model are regarded as valid.

With the assumption that the system is symmetrical, the consolute curve consists of the points at which the first derivative of ΔGm with respect to x vanishes. If the function Ψ is expressed as a power series in s=2x—1, one also obtains Tc—T, Tc being the critical temperature, as a power series in s. The experimental results on the consolute curves serve now to determine the coefficients of the power series, by which Ψ is given. Two additional assumptions are needed: (1) The coefficients of the high powers vanish in order to make use of the relation Ψ(1) = 1 and (2) the value of ΔGexc for T = Tc and x=0.5 is known approximately. With these assumptions the experimentally established flatness of the consolute curves leads to a curve for Ψ vs x having a double-maximum Ψ being greater than unity for high values of s, i.e., for great dilution of one component. This confirms earlier conclusions drawn from vapor pressure measurements and investigations of the volume change on mixing.

From a molecular point of view one can express this result by saying that the solvation of the diluted component is increased as compared to a perfect solution, even if the mixture is so strongly endothermic as to separate into two phases. The theoretical interpretation is not yet clear.
Absorption Spectra of Iodine and Bromine in the Gas Phase and ``Inert'' Solvents. I. Iodine
Authors: Evans Dennis F.
Published: April 2005

The strong absorption of iodine dissolved in paraffin hydrocarbons in the region of 2200 A—2600 A is not shown either by gaseous iodine or by iodine dissolved in perfluoroheptane (PFH) or di-perfluorohexyl ether, and is present only to a much smaller extent for iodine dissolved in chloroform.

The interaction of iodine with n-heptane has been studied quantitatively in PFH solution. It is concluded that the above absorption is a charge transfer transition due to a very weak, or possibly collisional type, complex, and is not a solvent shift of the N – V transition of the iodine molecule.
Magnetic Susceptibility and Free Energy of Graphite Bromide
Authors: Hennig G. R. , McClelland J. D.
Published: April 2005

The magnetic susceptibility of graphite bromide residue compounds has been measured by a Faraday method. The addition of bromine decreased the diamagnetism of graphite. Fair agreement was obtained between the measured diamagnetism and values calculated by assuming an undistorted graphite band structure depleted in electrons due to the dissociation and ionization of two out of eleven bromine molecules.

It has also been shown that the transfer of electrons from the graphite bands to bromine can account for the observed pressure dependence of the graphite bromine equilibrium.
Pulse Technique for Measurement of the Probability of Formation and Mobility of Negative Ions
Authors: McAfee K. B.
Published: April 2005

A new technique for measurement of the attachment coefficient of electrons to molecules has been devised. The technique involves production of a beam of electrons in an attaching gas. The transient current flowing after the initiation and termination of the electron beam is interpreted as a flow of negative ions produced by electron-molecule collisions. Analysis of the transient current which may last several milliseconds yields a value for the mobility of the negative ions thus formed. The ratio of the magnitude of the electron beam current to the negative ion current yields a direct measure of the attachment coefficient.

Preliminary results obtained with SF6 show a very large attachment coefficient. Values of α/p (the ratio of attachment coefficient to pressure) are considerably larger in SF6 than those obtained for O2 in studies elsewhere. As might be expected the mobility of negative ions formed in SF6 is much lower than that observed for other gases. This is attributed to the very large collision cross section resulting from (1) the interaction between the negative ion and neutral gas molecules comprising polarization attraction and hard sphere repulsion and (2) resonance or exchange interaction.
Ionic Conductance of Some Solid Metallic Azides
Authors: Jacobs P. W. M. , Tompkins F. C.
Published: April 2005

Measurements of the ionic conductance of several metallic azides have shown an unusually low activation energy for the structure sensitive conductance in potassium, calcium, and strontium azides. This is here associated with the mobility of surface lattice defects.
Hydrodynamic Frictional and Diffusion Coefficients in Idealized Liquids. I. The Collisional Contribution
Authors: Collins F. C. , Raffel H.
Published: April 2005

The approximate method of calculation of the collisional contribution to transport properties in liquids presented in an earlier paper is now extended to the calculation of the similar contribution to the frictional and diffusion coefficients. For the special case where the diffusing molecule is large compared to its neighbors, the calculated collisional contribution to the frictional coefficient is in good agreement with Stokes' law and the Langevin equation of colloid statistics is valid. However, for small diffusing molecules, the calculated frictional coefficient is not independent of the velocity of the given molecule. Numerical diffusion coefficients using molecular parameters obtained from sonic velocity data are about three times the experimental values as might be expected from the corresponding behavior of the calculated viscosity coefficient contribution previously reported. In spite of the failure of the Stokes equation for the frictional coefficient of small molecules, the Stokes-Einstein equation represents fairly satisfactorily the case of self-diffusion. This is due to the averaging over all velocities of the diffusing molecule.