bluuebunny/crossref_metadata_2025 huggingface dataset:
The Electrostatic Contribution to Hindered Rotation in Certain Ions and Dipolar Ions in Solution. II
Authors: Hill Terrell L.
Published: January 2005

The previous treatment of ethylene diamine, oxalic acid, glycine, α-alanine, leucine, α-amino butyric acid, and dithionic acid is extended here to analogous compounds with one additional angle of rotation: 1,3-propane diamine, malonic acid, β-alanine, and pyrophosphoric acid.
The Relation between ζ-Potential and the Electrical Capacity of the Double Layer
Authors: Eversole W. G. , Estee Charles R.
Published: January 2005

The usual calculation of the electrical capacity of the double layer from ζ-potentials is in error because (1) the electrogravitational plane of the outer charge is not at a distance 1/k and (2) the inner charge is not in the ζ-potential plane. An equation is derived which makes allowance for the distribution of charge on both sides of the ζ-potential plane. Calculations from ζ-potentials of glass in dilute aqueous solutions of simple salts give values which increase from about 1μf/cm2 at 10−5 molar to about 25μf/cm2 at high salt concentrations (1 molar). The equations are related qualitatively to electrocapillary phenomena.
The Variation in the Structure of Water in Ionic Solutions. II
Authors: Stewart G. W.
Published: January 2005

Earlier experiments with 15 strong electrolytes have been extended to 38 and there continues to be a striking correspondence between the rate of variation of the partial molal ionic volume with concentration and the rate of variation of water structure as crudely indicated by the x-ray diffraction pattern. The concentration in mole fraction of the solutions varied from 0.001 to 0.096 having a mean of 0.028. The influences of concentration on adiabatic compressibility and of solubility on the variation of water structure are mentioned. Qualitative explanation of the effect of the ions in solution may be obtained by assuming a direct effect on the breaking of H bonds and the indirect effect of altering the pure temperature expansion of the water.
Stability and Structure of Burner Flames
Authors: Lewis Bernard , von Elbe Guenther
Published: January 2005

It has been shown that the condition of equality of gas and burning velocities, required for stabilization of a flame above a burner, is established near the rim of the orifice or an obstruction within the stream by the effects of friction and inhibition of the explosive reaction. This condition is maintained between two critical gradients of the gas velocity at the solid surface, the lower gradient bordering on the flash-back and the upper gradient on the blow-off range. Values of the gradients in the range of laminar flow were determined by hydrodynamic equations from gas flow and tube dimensions; and their independence of tube diameter, except for extreme sizes, has been demonstrated both for upright and inverted flames. In the latter the critical velocity gradient for blow-off was also found to be independent of the diameter of the centrally mounted wire within a considerable range. The effect of the surrounding atmosphere on the critical blow-off gradient has been shown. The gas-flow pattern was studied experimentally by photographing stroboscopically illuminated magnesium oxide dust particles. No appreciable redistribution of velocities over the cross section of the stream was observed below the combustion zone. The burning velocity was found constant over the surface of the inner cone, except at the tip, where it increases to the axial gas velocity, and at the base, where it decreases to zero. The experimental flame cone outline and flow pattern agree with the theoretical within the limitations imposed by simplifying assumptions. The temperature distribution in the flame was determined by the sodium line-reversal method, only the center of the flame being colored, and observations of the width and emission spectrum of the luminous combustion zone were made. In natural gas-air flames C–C and C–H bands are observed in the zone, and the temperature rises gradually behind the zone to a maximum that corresponds to the theoretical flame temperature. In natural gas-oxygen flames no C–C or C–H bands are observed; and the temperature attains a maximum, exceeding the theoretical, immediately behind the combustion zone. Temperature distribution and flow pattern have been correlated. The flow pattern of inverted flames was also studied with particular attention to the region of flame attachment just above the central wire where the formation of an annular vortex is demonstrated. An interpretation of the formation of polyhedral flame cones, described by Smith and Pickering, has been given.
The Ratio Rule
Authors: Noether Hermann D.
Published: January 2005

An empirical rule for calculating the frequencies of isotopic groups in molecules is proposed and experimental evidence for it reported.
Vibrational Frequencies of the Isotopic Water Molecules; Equilibria with the Isotopic Hydrogens
Authors: Libby W. F.
Published: January 2005

The fundamental frequencies, anharmonicities, and vibrational modes for the molecules HDO, HTO, DTO, and T2O are calculated on the basis of Dennison's and Darling's recent analysis of the vibrational spectrum of the H2O molecule. The equilibrium constants for nine equilibria involving these molecules are given. Experimental values for the reactions HD+H2O=H2+HDO and HT+H2O=H2+HTO are compared with those calculated. It is concluded that the vibrational potential function is essentially unaltered by isotopic substitution.
Mechanical Properties of Polymeric Materials
Authors: Tobolsky Arthur , Eyring Henry
Published: January 2005

A molecular model in terms of which the elastic viscous properties of rubber-like substances can be interpreted is presented. Experiments on stress relaxation at constant extension, creep under constant load, extrusion, vibration, and breaking are discussed in terms of a mathematical formulation of this molecular model.
The Diffusion of Air Through Monel Metal
Authors: Coleman H. S. , Yeagley H. L.
Published: January 2005

The rate at which gases from the atmosphere diffuse through monel metal at various temperatures has been observed. An evacuated heavy-walled metal tube, a section of which was machined to a thin wall, was heated in a furnace. The rate at which the pressure inside the tube increased as a result of the diffusion of gases from the atmosphere was noted. The log R vs. 1/T curves, which are usually linear, show breaks about 900°C indicating some unusual physical change occurring in the alloy at this temperature. Dilatometric measurements on the same alloy were used to check the location of this break.
A Note Concerning l-Type Doubling in Linear Polyatomic Molecules
Authors: Nielsen Harald H. , Shaffer Wave H.
Published: January 2005

It is shown that certain Coriolis interaction terms in the rotation-vibration Hamiltonian of a linear polyatomic molecule give second-order contributions to the energy which remove the degeneracy of levels associated with the quantum number l of internal angular momentum arising from a doubly degenerate perpendicular mode of oscillation. This type of splitting is called ``l-type doubling'' because it is exactly like ``Λ-type doubling'' in the electronic energy levels of diatomic molecules.
Crystal Structure of Gadolinium Formate, Gd(OOCH)3
Authors: Pabst A.
Published: January 2005

The crystal structure of gadolinium formate has been studied by means of Laue, rotation, and powder x-ray patterns. It has a rhombohedral lattice. The unit cell, a0=6.17A, a=115° 30′, contains one molecule, Gd(OOCH)3. Density—(calculated) 3.85, (Berman balance) 3.77. By taking into consideration the symmetry of special positions all space groups except D37—R32 and C3v5—R3m can be excluded. A structure has been found in the latter group which yields excellent agreement of calculated and observed intensities.
Average H–H2 Repulsive Potential from Collision Cross Section Measurements
Authors: Amdur I.
Published: January 2005

The average repulsive potential between a hydrogen atom and a hydrogen molecule has been computed from experimental values of elastic collision cross sections for fast hydrogen atoms (with energies of 200 to 800 electron volts) scattered in room temperature molecular hydrogen. It was possible to solve the classical theory scattering equations explicitly for the repulsive potential by proper analytical representation of the experimental cross section values as a function of the relative kinetic energy of the scattering system. The potential function so obtained predicts total collision cross sections within the experimental error and has the form V(r)=A exp (−ar2)+B exp (−br2) where r, the distance between the mass points representing the hydrogen atom and the hydrogen molecule, extends, in the present case, from 0.28 to 0.70A. For r in A units, A = 0.846×10−10 erg, a = 24.9A−2, B = 0.211×10−10 erg and b = 2.40A−2.
The Quenching of Cadmium Resonance Radiation (3261A) by Hydrocarbons and Other Gases
Authors: Steacie E. W. R. , LeRoy D. J.
Published: January 2005

An investigation has been made of the quenching of cadmium resonance radiation (3261A) by a number of hydrocarbons and other gases. The following values of the quenching cross sections were obtained (in cm2 × 1016): H2 3.541−C4H835.2C2H6D2 1.802−C4H830.6C3H8NH3 0.052C6H628.4n−C4H10C2H424.9C2H222.0iso−C4H10C3H629.1cyclopropane0.71}ca. 0.02A few rough measurements have also been made with λ2288.
The Transference Numbers of Potassium Bromide in Aqueous Solution at 25°C
Authors: Keenan A. G. , Gordon A. R.
Published: January 2005

The transference numbers for aqueous solutions of potassium bromide at 25°C have been determined by the moving boundary method. Cells with cadmium bromide and lithium bromide as cation indicators and with potassium iodate as anion indicator were employed. The measurements are more difficult than with potassium and sodium chlorides; with sheared junctions, a thorough investigation of the effect of indicator concentration is necessary for each solution studied, and the same is true with both sheared and autogenic boundaries of the effect of current density. The results differ slightly from those previously reported by Longsworth, but are consistent with the known value of t+0. Potassium bromide also differs from the alkali chlorides and acetates in that the Longsworth function t+0′ is not linear in the concentration, thus precluding an independent extrapolation of the transference data.
The Structure of the Protein Molecule
Authors: Dervichian D. G.
Published: January 2005

A two-dimensional double layer of amino acids is postulated as the constitution of proteins in solution. From the known size of a single amino acid residue, the shape and size of a protein molecule of molecular weight class 3500 may be estimated. The denatured molecules are postulated to have a filamentous or fibrous form, characterized by the polypeptide chain. The evidence for such a postulate is reviewed.
Determination of Chlorine Vibrations in Dichlorobenzenes from Intensities and Polarizations of Their Raman Lines
Authors: Nordheim Gertrud , Sponer H.
Published: January 2005

Intensities and polarization properties of vibrations in which mainly chlorine atoms are participating, are investigated theoretically for the dichlorobenzenes. It is assumed that the change of polarizability in these vibrations is connected primarily with displacements of the chlorine atoms and that contributions from the individual atoms are additive. The Raman tensors belonging to the chlorine vibrations are then obtained by either adding or subtracting the single C–Cl contributions with reference to a chosen system of axes rigidly connected with the molecule. Intensity ratios were obtained for the symmetrical and unsymmetrical valence vibrations and deformation vibrations, respectively. Very small depolarization factors were found for lines representing symmetrical valence vibrations. For deformation vibrations the simplified theory gives complete depolarization for all allowed Raman lines. The results are discussed in connection with existing experimental data.
Theory of Dissolution of Gels
Authors: Tobolsky Arthur
Published: January 2005

A theory of the dissolution of three-dimensional cross linked polymers is presented. The existence of a definite melting temperature is discussed in terms of molecular constants characterizing the gel.
Raman Spectra of Hydrocarbons III. Diisobutylene, Cyclohexene, and Dipentene
Authors: Cleveland Forrest F.
Published: January 2005

Raman frequencies, relative intensities, and depolarization factors are listed for diisobutylene, cyclohexene, and dipentene. The relative intensities and depolarization factors were obtained with the aid of a Gaertner microdensitometer. The results are compared with data previously obtained for six olefins containing the groups XHC=CH2, XYC=CH2, or XHC=CHY (trans). The present compounds contain the groups XYC=CH2, XHC=CHX (cis), and XYC=CHZ. The first of these has nearly the same olefinic frequencies previously found for 2-methyl-1-heptene, except that the 1414 cm−1 frequency of the latter has dropped to 1376. The last two groups were contained in the similar ring structures of cyclohexene and dipentene and had nearly the same frequencies, except that the 1653 and 3023 cm−1 frequencies for XHC=CHX (cis) appeared at 1682 and 3012 for XYC=CHZ. Previous data for the three compounds are collected and compared with the present results. Lack of agreement between the present results in the 1100 and 3000 cm−1 region for diisobutylene and the previous data for 2,4,4-trimethyl-1-pentene is attributed to incorrect assignment of the exciting lines in the previous work.
The Scattering of Low Velocity Hydrogen Ions in Helium
Authors: Simons J. H. , Muschlitz E. E. , Unger L. G.
Published: January 2005

The low velocity scattering of H+, H2+ and H3+ in helium was measured. No neutralization was experienced and the potential laws were evaluated. For H+ in the range 3 to 130 volts (ra = 2.66 to 0.55A), V=−1.36×10−18r2.27. For H2+ in the range 4 to 50 volts (ra = 1.67 to 0.87A), V=−1.47×10−32r4. In the range 50 to 120 volts (ra = 0.87 to 0.66A), V=−1.31×10−32r4. For H3+ in the range 1.5 to 14 volts (ra = 2.22 to 1.59A), V=−3.9×10−53r6.68. In the range 14 to 65 volts (ra = 1.59 to 1.12A), V=−1.06×10−24r4.46. In the range 65 to 130 volts (ra = 1.12 to 0.89A),V=−4.83×10−24r3.01. The interaction of H+ in He shows the effect of the chemical combination to form HeH+. Assuming an equilibrium distance of 0.8A, the interaction energy is 3.27 ev. H2+ in He follows the law expected on the basis of the interaction of the charge on an ion with a polarizable molecule. The interaction of H3+ with He is more complex. An exact analytical treatment of the scattering problem shows that n, calculated from the experimental data by the previously used general approximate method, is correct. An exact numerical solution is given for the case n = 4 and several values of the mass ratio of ion to molecule and values of fc obtained, where fcKa = Ke. A less laborious method of calculating f, involving a simplifying assumption, is used; and it is shown that fc = f well within the precision of the experiments. A similar method is used to calculate f for the same mass ratios and n = 0, 1, and 2. A family of curves is obtained from which values of f can be interpolated for other values of n and mass ratio.
Infra-Red Absorption of Pyridine Vapor
Authors: Turkevich John , Stevenson Peter Cooper
Published: January 2005

The determination of the infra-red spectrum of pyridine vapor was of interest in this laboratory since its knowledge was necessary for the calculation of thermodynamic functions for possible pyridine syntheses. The spectrum for the liquid was measured by Coblentz and by LeCompte. These measurements, however, were carried on samples of unknown purity and the use of the results for frequency assignment is vitiated by the fact that selection rules which discriminate between various types of molecular vibrations, do not hold rigorously for molecules in the liquid state. The determination of the infra-red absorption spectrum was, therefore, carried out on a carefully purified sample of pyridine in the vapor state.
The Kinetic Theory of Rubber
Authors: Auluck F. C. , Kothari D. S.
Published: January 2005

The (isothermal) Young's modulus of ideal rubber is determined by statistical methods. The macro-state of a chain-molecule is here defined in terms of its length and not in terms of the distance between the ends of the chain. Section 1 deals with thermodynamical results holding for ideal rubber and in Section 2 the treatment based on ends-separation of the molecule-chain is described. Section 3 treats the problem on the basis of the length of the molecule-chain.
Viscosity and Structure of Pure Hydrocarbons
Authors: Kierstead Henry A. , Turkevich John
Published: January 2005

The two constants, A and E, of a two-constant equation, φ=A exp (—E/kT), for the fluidity φ, are tabulated for a number of hydrocarbons. The variations of these constants with structure are discussed.
A Direct Experimental Determination of the Electron Affinity of Oxygen
Authors: Vier Dwayne T. , Mayer Joseph E.
Published: January 2005

The electron affinity of oxygen atoms for one electron, the negative of the energy change at absolute zero of the reaction e−+Ogas→Ogas−,has been determined to be 70.8±2.0 kcal./mole. The method used was to determine the ratio of negative ions to electrons leaving a hot filament surface exposed to oxygen gas at a low pressure.
The Resonance Emission of Cadmium Hydride Bands in Cadmium Photosensitized Reactions of Hydrocarbons
Authors: Steacie E. W. R. , LeRoy D. J.
Published: January 2005

An investigation has been made of the resonance excitation of cadmium hydride bands in mixtures of ethylene or propane with cadmium vapor illuminated with λλ3261 and 2288. With λ3261 no resonance excitation with ethylene could be detected. With propane, CdH bands were emitted with fair intensity, thus proving that the primary process in the cadmium photosensitized reactions of the paraffins is Cd(53P1)+RH→CdH+R.With λ2288 no resonance emission could be detected, but the results were inconclusive.
Raman Spectra of Some Disubstituted Diacetylenes
Authors: Meister Arnold G. , Cleveland Forrest F.
Published: January 2005

Raman frequencies and relative intensities are reported for dimethyldiacetylene, diethyldiacetylene, dipropyldiacetylene, dibutyldiacetylene, and diamyldiacetylene. Depolarization factors also were obtained except for diethyldiacetylene. The relative intensities and depolarization factors were obtained with the use of a Gaertner microdensitometer. A tentative assignment was made of all the observed Raman frequencies of dimethyldiacetylene, assuming that it has the symmetry D′3h. Using the chain and methyl group frequencies thus established for dimethyldiacetylene, a comparison was made with the other spectra in order to determine how these frequencies are affected by introducing additional CH2 groups into the dimethyldiacetylene molecule. A comparison was made of the Raman spectra of the disubstituted diacetylenes with those of the corresponding acetylenes. For dimethyldiacetylene, three cases of Fermi resonance occurred, but there were also two cases where only a single line was observed, in spite of the fact that the frequency and symmetry conditions for resonance were satisfied. The carbon-carbon triple-bond frequency, which appears at 2183 cm−1 for diacetylene, increases to 2264 for dimethyldiacetylene, then drops to 2251–2257 for the other four compounds.
Dissociation of Methyl Chloride on a Hot Filament
Authors: Doty Paul M.
Published: January 2005

An experimental method for determining directly the bond energies in some polyatomic molecules is suggested, and the experimental data obtained in applying it to the case of carbon-chlorine bond in methyl chloride are presented and discussed. The decomposition of methyl chloride and carbon tetrachloride on hot tungsten is shown to be quite inefficient.
Equilibrium Distribution in Sizes for Linear Polymer Molecules
Authors: Tobolsky Arthur V.
Published: January 2005

Systems of linear polymer molecules are characterized by favorable heats of polymerization counterbalanced by unfavorable entropies of polymerization. Long chains are therefore formed and are stable at low temperatures while at sufficiently high temperature appreciable amounts of monomeric units split off. At any given temperature there exists a definite equilibrium distribution in sizes. This distribution is derived here by statistical methods and proves to be a very simple function of the heat of polymerization.
The Heat Capacity of Gaseous Butadiene-1,3
Authors: Aston John G. , Moessen Gustave W. , Hardy Howard C. , Szasz George J.
Published: January 2005

The heat capacity of gaseous butadiene-1,3 at 300°K and at 363°K has been determined by the measurement of the velocity of high frequency sound in the gas over the pressure range from one-third to one atmos. The heat capacity of the gas at zero pressure, evaluated by extrapolation to zero pressure, is in essential agreement with the value calculated from experimental state data. The experimental results are compared with values calculated from spectroscopic and molecular data and a marked disagreement is observed.
Thermal Isomerization of Butene-1 to Butene-2
Authors: McCarthy W. Walter , Turkevich John
Published: January 2005

The thermal isomerization of butene-1 was investigated in the temperature range of 450–550°C using infra-red absorption as a method of analysis. The vibrational spectra of butene-1, butene-2, and isobutene are reported.
Velocity of Sound and Molecular Association in Liquids
Authors: Lagemann R. T.
Published: January 2005

Two new, empirical criteria for determining molecular association in liquids are pointed out. One is the quantity PCR/TC in which R is a function of the velocity of sound; the other is the ratio of the velocity of sound in a liquid to the velocity of sound in the gas of the same compound. In both cases low numerical values of the ratios are qualitative indicators of association.
The Mercury Photosensitized Polymerization and Hydrogenation of Butadiene
Authors: Gunning H. E. , Steacie E. W. R.
Published: January 2005

An investigation has been made of the mercury (3P1) photosensitized polymerization and hydrogenation of butadiene. The main products of the reaction of butadiene with mercury (3P1) atoms are hydrogen, an acetylenic compound in the C4 fraction, dimer, and polymer. In the presence of excess hydrogen, the products are mainly butane, butene, and octanes. The variation of the rate of the polymerization reaction with time, and with the pressure of butadiene, suggests the following mechanism: C4H6+Hg(3P1)→C4H6*+Hg(1S0), followed by C4H6*+C4H6→2C4H6, or C4H6*+C4H6→(C4H6)2 or C4H6*→C4H4+H2. Polymerization arises largely by a free radical mechanism H2+Hg(3P1)→2H+Hg(1S0),H+C4H6→C4H7,C4H7+C4H6→C8H13, etc. The mechanism is shown to be consistent with the value found for the quantum yield.
Electrical Anisotropy of Xerogels of Hydrophile Colloids. Part II
Authors: Sheppard S. E. , Newsome P. T.
Published: January 2005

An improved, though still relative, quantitative expression has been derived for the electrical anisotropy E. A. The E. A. is a linear function of the elongation up to a certain limit, as is also the optical birefringence. The relation of electrical to optical anisotropy has been studied in greater detail. A more critical discussion in terms of atomic model structures is given of the hypothesis that E. A. in the compounds studied is due to the formation of continuous parallel chains of hydrogen bridges, having electronically conducting character: The materials studied were: polyvinyl acetate and its hydrolyzed stages down to polyvinyl alcohol, cellulose acetate and its hydrolyzed stages down to (hydrate) cellulose.
The Mercury-Sensitized Reaction Between Hydrogen and Nitric Oxide
Authors: Taylor H. Austin , Tanford Charles
Published: January 2005

The reaction of hydrogen atoms with nitric oxide has been studied by mercury sensitization of various mixtures of hydrogen and nitric oxide to produce nitrogen and water. The rate at constant nitric oxide pressure is proportional to the hydrogen at low hydrogen pressures, the effect diminishing at higher concentrations. With a given hydrogen concentration nitric oxide is almost without effect until an excess is present when it shows a retardation. At constant total pressure a maximum rate occurs with a particular excess of hydrogen. A mechanism based on HNO radicals has been postulated. These radicals decompose by a wall reaction to give nitrous oxide which is rapidly reduced to nitrogen.
The Electrostatic Contribution to Hindered Rotation in Certain Ions and Dipolar Ions in Solution. III
Authors: Hill Terrell L.
Published: January 2005

In the present paper we shall extend the previous methods to a relatively complicated molecule, glutamic acid:  COOH (1)  | CHNH3+ (3)  |(CH2)2  | COOH (2).Other calculations will also be made and an empirical relationship among the effective dielectric constants found in this and earlier papers will be pointed out.
The Principles of Thermodynamics
Authors: Leaf Boris
Published: January 2005

A formulation of thermodynamics has been developed which points out the restrictions of classical treatments. This formulation in terms of potential and charge concepts predicts the property ascribed to the entropy of increasing during thermodynamic processes and leads to an equation for entropy produced and heat dissipated in irreversible processes. The postulates of the treatment presented have allowed deduction of a generalized form of the second law of thermodynamics which applies to each energy field of the system. These concepts have been further developed in discussion of the phase rule; the functions H, A, and F; a generalization of Kelvin's postulate; and a generalization of the Carnot cycle. The results obtained have permitted derivation of the principles of Brønsted's system of energetics.
The Electrostatic Contribution to Hindered Rotation in Certain Ions and Dipolar Ions in Solution. IV
Authors: Hill Terrell L.
Published: January 2005

The present communication is essentially a refinement of the earlier papers of the same title. This refinement is made possible by adopting particular models to represent the shape of molecular cavities, following Kirkwood and Westheimer. An important consequence of this procedure is that the effective dielectric constants used are no longer constant, but vary with intercharge distance. It is pointed out that a more detailed treatment of the molecular shapes involved should lead to further improved calculations.
The Asymmetric Rotor II. Calculation of Dipole Intensities and Line Classification
Authors: Cross Paul C. , Hainer R. M. , King Gilbert W.
Published: January 2005

A table of line strengths for rigid asymmetric rotors is given, by means of which to this approximation the relative intensities of all important rotational lines up to J < 13 for all bands of any molecule can be readily calculated, provided the asymmetry is roughly the same in the initial and final states. A classification of the irregularly spaced lines of the asymmetric rotor is made into ``sub-branches'' defined by the changes of the K values of the initial level in the limiting prolate and oblate symmetric rotors, and into ``wings'' which collect together lines of the sub-branches which have uniformly varying strength and Boltzmann factor, and fairly uniform spacing.
Electrical Anisotropy of Xerogels of Hydrophile Colloids Part I
Authors: Sheppard S. E. , Newsome P. T.
Published: January 2005

A number of colloid materials—proteins, plastics, and the like—have been coated in sheet form and ``fibered'' internally by stretching to 100 percent or more elongation. Circular disks were cut from the fibered sheets, and their degree of orientation measured in an (alternating) electric field. Account is given of the relation of the orientation measured to field strength, thickness, humidity, and moisture content. It was observed that induced electrical anisotropy is not shown by all kinds of natural and synthetic colloids; thus it is not shown by organophile xerogels, but only by the hydrophile ones. With most of these the electrical response depends upon the relative humidity and the absorbed water content, but with polyvinyl alcohol the effect was independent of the absorbed water.
Raman Spectra of Hexachloroethane and Hexabromoethane
Authors: Hamilton Dwight T. , Cleveland Forrest F.
Published: January 2005

Raman frequencies, relative intensities, and depolarization factors are reported for hexachloroethane and hexabromoethane. The relative intensities and depolarization factors were obtained by use of a Gaertner microdensitometer. The fundamental frequencies of hexachloroethane were used to calculate force constants from the equations used by Stitt for ethane. The Raman data indicate that the equilibrium configuration for hexachloroethane is that corresponding to the point group D3d. The force constants so obtained were then used to calculate the values of the frequencies that are allowed by the selection rules in the infra-red spectrum. Selection rules for the fundamentals, binary combinations, overtones of non-degenerate frequencies, and overtones of degenerate frequencies up to the fourth overtone for any molecule whose symmetry is D3h, D′3h, or D3d were worked out and are discussed.
Polymer Spectra of a Cyanine Dye
Authors: Mattoon Richard W.
Published: January 2005

In dilute aqueous solutions the dye 1,1′-diethyl-2,2′-cyanine chloride, a photographic sensitizer, has two broad molecular absorption bands with maxima at 4900 and 5230A. For a 10−2 molar water solution at room temperature, which is a gel, a new, intense, and exceedingly narrow absorption and fluorescence band has been found at 5730A by G. Scheibe, and by E. Jelley by other methods. The electric polarization of this band in both absorption and fluorescence is parallel to the long dye polymers formed in the gel. In the present investigation the occurrence and behavior of this ``P band'' were studied for thin dye films deposited on glass from solutions containing water. The P band shifts about 50A to greater wave-length, becomes broader and weaker, and finally disappears as the water is removed by pumping and/or by increasing the temperature. This behavior is reversible if water vapor is readmitted. The position of the P band enables a measurement of the humidity of the atmosphere surrounding the film. The effect of temperature from −195 to +100°C is described. The P band can be made to appear starting with water solutions as dilute as 10−5 M by freezing the water, locally concentrating the solution. For dye films, there is observed a second, weaker absorption band (called the PM1 band) at 5430A similar to the P band in structure and behavior but polarized perpendicular to the polymer chains and requiring a higher dye concentration before appearing. Reasons discussed in the paper indicate that the P band is due to single dye polymer chains while the PM1 band should belong to a system of coupled chains lying mutually parallel and forming threads. These threads were observed microscopically. A dehydrated film may contain a fraction of the dye molecules in monomeric form, another fraction (showing only the molecular bands much broadened) in an array anchored to the supporting surface such that the mere addition of water vapor immediately produces the polymer chains with the P and PM1 bands, and the remainder in crystalline form with a broad absorption band at 5650 and a broad fluorescence band at 6200A. Experiments undertaken to determine the number of water molecules per dye molecule necessary for polymerization were only sufficient to determine that the order of magnitude of the ratio is from 1 : 2 to 10 : 1. An attempt is made to interpret the absorption and fluorescence bands of the polymer chains by the hypothesis of exciton migration.
The Effect of Substituents on the Dissociation Constants of Carboxylic Acids
Authors: Sarmousakis James N.
Published: January 2005

The Kirkwood-Westheimer electrostatic theory for relative acid strength has been extended by the use of an oblate spheroidal molecular model and applied to the study of a number of substituted benzoic acids. When reasonable values of certain structural and electrical parameters, describing the acid and base molecules in equilibrium, are used, the agreement between theory and experiment with respect to the meta acids is good. The theoretically calculated and experimentally determined values of log Kaxb0 for the parasubstituted acids, where Kaxb0 is the ratio of the dissociation constant of the substituted acid to that of the parent acid, show differences Δ log Kaxb0 which may be considered measures of the resonance effects operative in the para acids. The quantity Δ log Kaxb0 for each acid changes very little from one single-component hydroxylic solvent to another.
The Thermodynamic Properties and Potential Energy of Solid Argon
Authors: Rice O. K.
Published: January 2005

In an earlier paper an attempt was made to obtain the interatomic potential for a pair of argon atoms, using the specific heat data at low temperatures and a theory in which the Debye characteristic temperature Θ was related to the curvature of the interatomic potential energy curve. Difficulties in accounting for certain other experimental data were explained on the supposition that disorder sets in in the solid below the melting point. As there are certain objections to this point of view, a new calculation is presented herewith in which the Debye theory is assumed to hold throughout, and Θ and the potential energy of the solid are calculated independently of each other from the available experimental data on the specific heat at low temperatures, and on the equation of state at high pressures. A consistent picture of the thermodynamic properties of solid argon is thus obtained, but the interatomic potential curve for a pair of atoms differs greatly from that obtained by the method used previously. The interatomic potential curve found here shows extreme change in curvature near the minimum. This change in curvature is so great that, if the result is correct, the theory of small vibrations will not be applicable, and it will not be possible to relate Θ to the curvature, as was done in the earlier work. The significance of this conclusion for the theory of the solid state is discussed.
A Method for Determining Small Quantities of Oxygen
Authors: Pollack Manfred , Pringsheim Peter , Terwoord Dolores
Published: January 2005

A method is described which permits one to follow the production rate of minute quantities of oxygen. The method is based on the quenching of the phosphorescence of a dye adsorbed on silica gel. Examples of the application of the method are discussed.
The Vibrational Spectrum of Pyridine and the Thermodynamic Properties of Pyridine Vapors
Authors: Kline Charles H. , Turkevich John
Published: January 2005

An analysis of the vibrations of the pyridine molecule was made on the basis of infra-red, Raman, and ultraviolet absorption spectra. The fundamental frequencies were assigned and the thermodynamic properties of pyridine were calculated on the basis of such an assignment.
The Molecular Structure and Thermodynamics of Propane The Vibration Frequencies, Barrier to Internal Rotation, Entropy, and Heat Capacity
Authors: Pitzer Kenneth S.
Published: January 2005

A substantially complete picture is proposed for the vibrational and torsional motions of the propane molecule. The vibrational assignment of Wu and Barker is extended and slightly revised so that definite values are assigned to all normal modes. It is believed that, with possibly one exception, all are correct within 2 percent. Comparison with the experimental entropy and heat capacity shows excellent agreement. The free energy, heat content, and heat capacity functions are then calculated over the range 180 to 1500°K. By obtaining the fundamental frequency of one torsional mode from a combination band in the infra-red spectrum, it was possible to evaluate the other from the entropy. The force constants calculable therefrom indicate that the apparent increase of potential barrier from ethane to propane arises from interaction of methyl group hydrogen atoms. For that mode in propane where these distances remain larger the torsional force constant is the same as that for ethane.
An Empirical Correlation and Method of Calculation of Barriers Hindering Internal Rotation
Authors: Aston John G. , Isserow Saul , Szasz George J. , Kennedy Robert M.
Published: January 2005

The barriers hindering internal rotation of methyl groups can be calculated by assuming that they are solely due to repulsion between hydrogen atoms according to the law Vij=4.99 ×105/rij5. For dimethyl ether, dimethyl sulfide, and propylene the empirically calculated values are low. This discrepancy is discussed. This treatment is applied to ethyl and isopropyl alcohol and several normal paraffins. The resulting entropies, heat capacities, and equilibrium constants are compared with the available experimental data.
Magnetic Studies of Chromium Oxide Catalysts
Authors: Turkevich John
Published: January 2005

The magnetic susceptibility of active chromium oxide gel and ``glowed'' inactive chromium oxide was measured from liquid air temperature to 444°C and no difference in magnetic behavior was noted. Activated adsorption of hydrogen does not markedly affect the magnetic susceptibility of the active gel catalyst. The interaction of chromic nitrate with ammonia, filtration, and drying results in a chromium oxide intermediate in oxygen content to Cr2O3 and CrO3. Revivification of the catalyst by oxygen treatment results in a similar chromium oxide. Mechanism for the preparation of an active chromium oxide catalyst and a structure for such an oxide have been proposed.
Raman Effect of Acetylenes II. Diiodoacetylene, Liquid Acetylene and Deuteroacetylenes
Authors: Glockler George , Morrell Charles E.
Published: January 2005

An apparatus consisting of eight discharge tubes for Raman work has been designed which is more convenient than the usual helical design of these light sources. It is possible to arrange these eight tubes concentrically around a Raman tube of any diameter. Cylindrical filters of any dimensions can be interposed with great convenience. The vibration Raman spectra of C2I2: 191.3, 310.2, 627.0 688.2 and 2109.4; liquid C2H2: 381.6, 618, 631, 1762, 1959 and 3338; gaseous C2H2: 1973.8 and 3373.7; gaseous C2HD: 1851.2 and 3334.8; gaseous C2D2: 1762.4 and 2700.5 cm—1 have been observed and are interpreted in the usual manner on the basis of symmetry considerations. Striking differences in the spectra of liquid and gaseous acetylene (C2H2) indicate a serious distortion of the molecules in the liquid state. The extent of this disturbance seems to change completely the symmetry of the molecules of the liquid which are no longer linear as in the gaseous state. Certain Raman lines are accompanied by faint satellites which fit a rotation formula and may be due to rotation effects. The free energies of C2HD and C2D2 were calculated and the free energy change of the reaction C2H2+C2D2⇆2C2HD has been evaluated and the equilibrium constant determined for a series of temperatures.
Determination of the Thorium Content of Rocks
Authors: Urry Wm. D.
Published: January 2005

A new method for the determination of thorium in quantities of the order of 10—5 to 10—6 g is employed to complete the data necessary for the calculation of the age of geological material. The alpha-particle activity of thoron in a streaming gas is measured with a counter, a procedure which is shown to be superior to the usual ionization measurements on the thoron deposit. Simultaneously, the Pa/Ra ratio in common rocks can be determined.
On the Zero-Point Energy of an Activated Complex and the Reaction 2NO+O2→2NO2
Authors: Rice O. K.
Published: January 2005

Considerations, based on the uncertainty principle, have been brought forward which indicate that a reaction, whose rate is determined solely by a transitory activated complex in the formation of which classical degrees of freedom must be frozen out into vibrations, must have a positive activation energy at all temperatures, which increases with the temperature. A negative activation energy must mean the formation of a more or less stable intermediate compound, or ``molecular complex.'' The theory has been applied to the reaction 2NO+O2→2NO2.
The Structure of Ice II
Authors: McFarlan Ronald L.
Published: January 2005

The stability of the high pressure ice forms discovered by Tammann and Bridgman at very low temperatures and atmospheric pressure has made it possible to obtain x-ray powder diffraction photographs of these forms. The experimental procedure is very briefly discussed. An analysis of the ice II diffraction patterns leads to a side-centered orthorhombic cell with a=7.80A, b=4.50A, and c=5.56A. This cell contains eight molecules, has the symmetry of space group V5—C2221, and gives a value for the density of 1.21. The proposed arrangement of the hydrogen atoms indicates that the transition from ice I to ice II breaks up the water molecule, and that ice II is an ionic crystal. According to the model described the effect of a pressure of 2100 atmospheres in forming ice II is: (1) To decrease the packing volume of the oxygen ion approximately three percent; (2) To break down the open ice I structure by a slipping of the oxygen ion layers relative to each other; (3) To give a four-coordinated structure where each oxygen is surrounded by a badly distorted tetrahedron of oxygen ions.
The Rate of Thermal Decomposition of Deuterium Iodide
Authors: Blagg John C. L. , Murphy G. M.
Published: January 2005

The partition functions for deuterium iodide have been calculated at temperatures from 300 to 1500°K. Constants were calculated for an equation to give the value of the free energy function at any temperature within this range. A similar calculation was made for D2 using the data of Johnston and Long. Combining these with the data for the other molecules involved, the equilibrium constant for the decomposition of deuterium iodide and for the exchange reaction was calculated. These results can be differentiated and integrated to give values for ΔH0, ΔCp and ΔS0. The equilibrium constant for the reaction H2+2DI⇄D2+2HI has been plotted against the temperature from 300 to 1500°K. The equilibrium constant for the reaction DI ⇄½D2+½I2 has been calculated. The rate of thermal decomposition of deuterium iodide was measured between 660 and 719°K. The experimental ratio of the rate constants for the reactions HI→½H2+½I2 and DI→½D2+½I2 has been compared with the theoretical value of Wheeler, Topley and Eyring. Contrary to their expectations, it was found to be lower than the theoretical value.
The Far Ultraviolet Absorption Spectrum of N2O
Authors: Duncan A. B. F.
Published: January 2005

The absorption spectrum of nitrous oxide below 2200A has been reinvestigated. Much new material has been found, particularly below 1550A, including some discrete systems of bands, and some continuous regions of absorption. No bands are found below 997A, but only continous absorption down to about 850A, the limit of observation. A Rydberg series was found, converging to an ionization potential of 12.66 volts. Evidence was found for a total of ten electronic states including the members of the Rydberg series. The vibration frequency in the electronic transition around 1500A is 621 cm—1.
Liquid Hydrogen Chloride. Electrical Conductance and Dielectric Constant
Authors: Glockler George , Peck R. E.
Published: January 2005

Liquid hydrogen chloride has a specific electrical conductivity of 0.35×10—8 reciprocal ohms at —85°C. The temperature coefficient is negative: —0.65×10—10 in the range from —84°C to —64°C. The molecular conductivity at infinite dilution is estimated to be 184 (—85°C) and 192 (—53°C). The ionization constant is 0.083×10—16 at —78°C and 0.051×10—16 at —68°C. The change in heat content of the ionization reaction is: (x+y+2)HCl→(H2Cl·HClx)++(Cl·HCly)−,  ΔH195≐−3500 cal.
Absolute Rates of Four-Atom Reactions
Authors: Altar Wm. , Eyring H.
Published: January 2005

Equipotential surfaces such as one encounters in valence problems and particularly in the calculation of absolute rates, are discussed in a ``bond space'' instead of configuration space, with much simplification resulting both in the general aspects and in the practical handling of such problems. The exchange part, as well as the so-called coulombic part, of the bond energies is seen to obey a simple vector addition rule. A complete treatment of a four-atom reaction without symmetry (H2+ICl→HI+HCl) is carried out and results are compared with the existing experiments.
The Production of Hydrogen Peroxide in Water by Alpha-Rays
Authors: Nurnberger Carl E.
Published: January 2005

The ultraviolet absorption spectrum of air-free water irradiated with alpha-rays has been photographed between 2200 and 2800A. The spectrum appears to belong to a dilute aqueous solution of hydrogen peroxide. The gases evolved from the irradiated water contain hydrogen in excess of an electrolytic mixture. The parallel variation of excess H2 pressure and H2O absorption is consistent with Duane and Scheuer's hypothesis. Apparatus has been developed in which excess H2 and H2O absorption can be measured simultaneously at different times without disrupting the normal course of an experiment. The method is applicable to other radio and photochemical reactions.
The Entropy of Carbon Tetrachloride
Authors: Lord R. C. , Blanchard E. R.
Published: January 2005

A new calculation of the entropy of carbon tetrachloride has been made from Raman spectra and electron diffraction data. The effect of the isotopes of chlorine has been investigated. A new value of the calorimetric entropy has been computed from recent (and in part unpublished) thermal data. The agreement of the entropies is sufficiently good as to leave little reason to doubt the validity of the spectroscopic calculations.
The Role of Molecular Orientation in Photochemical Reactions in Monolayers
Authors: Mitchell Joseph S.
Published: January 2005

The theory of the dependence, on the molecular orientation, of the velocity of photochemical reactions in monolayers at the surface of aqueous substrates is developed. The molecular extinction coefficient in the film is discussed and a definition is given of the ``apparent quantum efficiency.'' Consideration of the molecular thermal agitation suggests the possibility of a phase boundary potential gradient of the order of 108 volts per cm. Under certain conditions, the apparent quantum efficiency is proportional to the absolute temperature. Factors modifying the absorption spectrum of a compound in a monolayer are discussed. By an application of the general theory of radiation, a relation is obtained between the molecular orientation and an integral of the molecular extinction coefficient in the film over the absorption band. The molecular extinction coefficient in the film cannot be deduced a priori from that in solution; it is proportional to the mean value of sin2θ (where θ is the angle between the molecular dipole axis and the direction of the incident light) and is usually of the order of 3/2 sin2θ that in solution. The theoretical accuracy of the sin2θ relation is discussed and both quadrupole absorption and reabsorption of coherently scattered radiation are shown to be of no practical importance. Direct measurement of the absorption spectrum of a monolayer is essential for the absolute determination of the quantum efficiency of a photochemical reaction.