bluuebunny/crossref_metadata_2025 huggingface dataset:
Free Energy and the Rate of Chemical Reactions The Relation Between the Rate and Oxidation-Reduction Potentials
Authors: Gershinowitz Harold
Published: January 2005

The theories of the rates of chemical reactions previously developed by Eyring, Rice and the author give a relationship between the rate of reaction and the free energy of formation of the activated state. With the aid of this relation it is possible to explain the experimental data which have shown that there is a connection between the rates of oxidation-reduction reactions and the potentials of the reagents used.
On the Thermodynamic Properties of Nitric Oxide An Example of an Associated Liquid
Authors: Rice O. K.
Published: January 2005

Liquid nitrix oxide consists largely of double molecules, as evidenced by the abnormally high entropy of vaporization and the high and variable specific heat. By making use of these data it is possible to calculate the extent to which single molecules exist in the liquid, the heat of dissociation of the double molecules, and the value the specific heat would have were the association in the liquid complete. A statistical calculation is made of the entropy of vaporization, and the result compared with the experimental value. An estimate is made of the heat of dissociation in the gas phase.
Determination of Molecular Structure by Electron Diffraction
Authors: Ackermann Philip G. , Mayer Joseph E.
Published: January 2005

(1) An apparatus has been designed and built for the purpose of determining molecular structure by electron diffraction using 6400 volt electrons. (2) The apparatus was checked with carbon tetrachloride whose structure is accurately known, and the interatomic distances in, and configurations of, a number of compounds determined. (3) Ethylene oxide was found to be a three membered ring with a carbon-carbon distance of 1.56±0.05A, a carbon-oxygen distance of 1.45±0.05A and a carbon-hydrogen distance of 1.05±0.07A. (4) Sulfur monochloride was found to have the two chlorine atoms attached to different sulfur atoms, the sulfur-sulfur distance was found to be 2.04±0.05A, the sulfur-chlorine distance of 1.98±0.05A and an angle of 105±5° between bonds. (5) In acetaldehyde the carbon-oxygen distance was found to be 1.20±0.05A, the carbon-carbon distance 1.51±0.05A and the bond angle 122±5°. (6) Paraldehyde was found to have a puckered ring structure with a carbon-oxygen distance of 1.41±0.05A, a carbon-carbon distance of 1.52±0.05A and the tetrahedral angle of 109° between bonds.
An Analytic Method of Interpretation of Electron Diffraction Photographs of Gases
Authors: Bauer S. H.
Published: January 2005

An analytic procedure to be used in the interpretation of electron diffraction photographs for gases is developed. The experimentally determined positions of the maxima and minima are employed to solve directly for the interatomic distances through successive approximations. The method is then generalized so as to be applicable to molecules in which rotations or large oscillations about a bond are permitted. As a test, three sets of data which have already been published are recalculated yielding somewhat altered values for the molecular parameters. New diffraction photographs of propane are analyzed. It is pointed out that the number of theoretical intensity curves which must be computed to obtain the correct structure is thereby greatly reduced.
Spectroscopic Studies of the Simpler Porphyrins I. The Absorption Spectra of Porphin, ms-Methyl Porphin, ms-Ethyl Porphin, ms-Propyl Porphin and ms-Phenyl Porphin
Authors: Albers V. M. , Knorr H. V.
Published: January 2005

The molecular absorption coefficients of porphin and four ms-substituted porphins have been measured throughout the visible region and the curves showing absorption coefficient as a function of wave-length are shown. All of the substances have a very strong absorption band at the violet end of the visible region. The rest of the spectrum, while similar in pattern for all of the substances, shows some characteristic differences.
Analysis of Rotatory Dispersions of Configurationally Related Halides
Authors: Levene P. A. , Rothen Alexandre , Marker R. E.
Published: January 2005

The rotatory dispersion curves of halides of the type     CH3     |H−C−(CH2)nX     |    R(where X=halogen atom, R=alkyl group) have been analyzed in the visible and the ultraviolet regions. The three halogen atoms function similarly with respect to the character of the rotatory dispersion curve in substances of identical structure. A periodicity is observed in the sign of some of the partial contributions of the halogen atom with the progressive increase in the value of n. The course of the rotatory dispersion of the halides with n=1 is anomalous. An attempt was made to apply the results of the observations obtained on substances having n>0 to elucidate the sign of rotation of the configurationally related substances having n=0.
The Absorption Spectrum of Methyl Alcohol Vapor in the Photographic Infrared
Authors: Badger Richard M. , Bauer Simon H.
Published: January 2005

The absorption of methyl alcohol vapor in the photographic infrared has been explored under low dispersion. Absorption regions were found at λ9500 and λ7300, which correspond to two harmonics of the O–H vibration, and at λ12,000 which is a harmonic of the C–H vibration. The two O–H harmonic bands were investigated under high dispersion and a somewhat complex rotational structure was resolved. The complete interpretation of the spectrum must be postponed until the theory of the torsion oscillator rotator is further developed.
The Continuous Absorption Spectrum of Bromine: A New Interpretation
Authors: Acton A. P. , Aickin R. G. , Bayliss N. S.
Published: January 2005

The continuous absorption spectrum of bromine was investigated quantitatively at six temperatures from 293°K to 906°K, and the contributions of the vibrational levels v″ = 0 and v″ = 1 to the total continuum were deduced from the variation of the absorption coefficients with temperature. Contrary to expectation, the absorption from the level v″ = 1 has three maxima and not two, and the absorption from v″ = 0 has a decided hump on the long wavelength side of the maximum. These results can be explained if the bromine continuum is composed of two overlapping continua, the stronger one (A) with its maximum at λ4150, and the weaker (B) with its maximum at λ4950. Although it is possible to assign A to the transition 3Π0+u←1Σg+, and B to 3Π1u←1Σg+, better agreement with the Franck-Condon principle is obtained if A is assigned to 1Πu←1Σg+, and B to 3Π0+u←1Σg+. The latter interpretation is also correlated with what is known of the chlorine and iodine continua. On either assumption, the value of re for 3Π1u of bromine is predicted to be about 2.6A.
The Normal Vibrations and the Isotope Effect of Molecules of the Type X2YN with an N-Fold Axis of Symmetry
Authors: Schimmel Herbert
Published: January 2005

In the present study it is assumed that the Y atoms are at the corners of a regular polygon and the X atoms are symmetrically situated on the N-fold axis of symmetry. The frequencies are calculated in terms of the parameters of a general quadratic potential energy form, the masses, and the geometrical constants of the figure. Frequency shifts due to isotopes are also calculated.
Thermodynamic Properties of Phosphorus Compounds
Authors: Anderson Thomas F. , Yost Don M.
Published: January 2005

With Raman spectrum, electron diffraction and existing equilibrium data the standard virtual entropies of P(s, white), P4(g). PCl3(g), PCl3(l), PCl5(g), and PCl5(s) are calculated to be 10.55, 66.88, 74.7, 52.8, 87.7, and 40.8 cal./deg. respectively. The corresponding standard free energies of formation are calculated to be (0), 5850, —64,650, —63,570, —72,540 and —77,950 cal., respectively.
The Far Ultraviolet Absorption Spectra and Ionization Potentials of the Alkyl Halides. Part I
Authors: Price W. C.
Published: January 2005

The absorption spectra of methyl iodide, bromide and chloride have been examined in the region 2000–1000A. The analysis shows that the bands are due to the excitation of non-bonding electrons localized on the halogen atoms. They can be fitted into Rydberg series which go to the two components of the doublet state of the molecular ion as limits. The values of the ionization potentials so determined are 9.49 and 10.11 volts for methyl iodide, 10.49 and 10.80 volts for methyl bromide, and 11.17 and 11.25 volts for methyl chloride. The separation of the two ionization potentials is in excellent agreement with those predicted by R. S. Mulliken, though their actual values are somewhat lower. The electronic and vibrational nature of the bands is discussed and some correlation of the spectra of the three molecules is made.
The Far Ultraviolet Absorption Spectra and Ionization Potentials of the Alkyl Halides. Part II
Authors: Price W. C.
Published: January 2005

The absorption spectra of the ethyl and higher halides have been examined in the region 2000–1000A. It has been found that they are essentially similar to those of the methyl halides. The ionization potentials of ethyl iodide are given as 9.30 and 9.88 volts and those of ethyl bromide as 10.24 and 10.56 volts. The ionization potentials of the higher halides cannot be determined exactly because of the presence of continuous absorption from the C–C and C–H bonds, and of the diffuseness of the bands themselves. However there is strong evidence that the ionization potentials of consecutive members of the homologous series diminish asymptotically to a limiting value, the diminution from methyl to ethyl being by far the greatest. A comparison of the way the ionization potentials diminish and the dipole moments of the carbon-halogen bonds increase as we ascend the homologous series indicates a definite connection between the two phenomena.
The Radiochemical Synthesis and Decomposition of Hydrogen Bromide
Authors: Eyring H. , Hirschfelder J. O. , Taylor H. S.
Published: January 2005

A theory is developed for the radiochemical synthesis and decomposition of hydrogen bromide which makes use of experimentally known processes of ionization, the known rates of a few simple chemical reactions, and the extensive experimental results of Lind and Livingston. The analysis indicates that in pure hydrogen gas, six hydrogen atoms are formed per ion pair; in pure hydrogen bromide, six hydrogen bromide molecules would be decomposed; and in equal mixtures of Br2 and HBr the chance that an electron will form negative ions with HBr (HBr +ε→H+Br—) is greater than with Br2.
Thermal Transitions in Copper Sulphate Pentahydrate Molecular Rotation and the Dehydration of Hydrates
Authors: Taylor T. Ivan , Klug Harold P.
Published: January 2005

A study of the thermal transitions in copper sulphate pentahydrate has been made from warming curves obtained by a differential thermocouple method. Small transitions were observed at 29°C, 35°C, 53.7°C, and dehydrations at 96.5°C, 102°C, and at 113°C. The first three of these may be interpreted as transitions from oscillation to rotation of the water molecules in the crystal. The last three are associated with the stepwise dehydration to the tetra-, tri-, and monohydrates, respectively. The existence of the tetrahydrate, not previously known, has been demonstrated. A discussion of the dehydration in the light of its crystal structure is given. A mechanism of dehydration by heat, based on the concept of molecular rotation, has been suggested.
The Analysis of Isotopic Mixtures of Deuteromethanes and Ethanes by Infrared Absorption Spectra
Authors: Benedict W. S. , Morikawa Kiyoshi , Barnes R. Bowling , Taylor H. S.
Published: January 2005

The infrared absorption spectra of a large number of deuterium-containing methane samples, and a few of ethane, have been studied with a rocksalt spectrometer. All the observable fundamental frequencies of each individual methane isotope have been identified, and from the relative intensity of absorption at various characteristic wave-lengths the composition of any mixture of these isotopes may be determined. The infrared spectra of deuteroethanes including C2D6 have been observed.
The Raman Spectra of Some Simple Molecules in Solution
Authors: West W. , Arthur Paul
Published: January 2005

The Raman spectra of HCl, HBr, SO2 and NH3 in various nonionizing solvents indicate vibrational frequencies in the solute molecules of lower value than in the corresponding gaseous states, the relative diminution amounting, in the hydrogen halides dissolved in some solvents, to 3 percent of the gas frequencies. The frequency shift is smaller for the two polyatomic molecules. There seems to be a definite relation between the relative frequency displacement and the dielectric constant of the solvent for the dissolved molecules of HCl and HBr. Δv/v increases with solvent dielectric constant to a limiting value of 0.03. A similar trend is shown in SO2 and for NH3 it seems that other factors than the dielectric constant of the solvent are effective in determining the frequency displacement. Concentrated solutions of HCl and HBr in several ionizing solvents have no features in their Raman spectra which can be identified as vibrations in HCl or HBr molecules. The bearing of these results on the dissociation process of HCl in solvents is discussed.
The Infrared Absorption Spectrum of Hydrogen Chloride in Solution
Authors: West William , Edwards Roy T.
Published: January 2005

The near infrared absorption bands of HCl in nonionizing solvents in the neighborhood of 3.5μ and 1.8μ, measured with a 3600 line per inch grating, have the following characteristics; they show no rotational structure; they usually have two components of unequal intensities; the absorption region is displaced towards lower frequencies compared with the gas. The displacement is independent of concentration up to mole fraction 0.1, but increases with diminishing temperature in certain solvents. The interval between the components varies directly with the dielectric constant of the solvent. In solution, the relative displacement of the more intense component from the origin of the gas band is approximately the same for the 3.5μ and 1.8μ bands, as is also the interval between components. A simple relation exists approximately between the frequency displacement from the gas origin and the dielectric constant of the solvent, of the form Δv/v=C[(D—1)/(2D+1)], a deduction of which formula has been made by J. G. Kirkwood. The more intense component, whose relative shift from the gas origin is within the limits of error the same as the corresponding shift in the Raman spectrum, is interpreted as originating in the internuclear vibration, and it is tentatively suggested that the other component represents a combination between such vibrational transitions and some slow intermolecular vibration between HCl and solvent molecules. The effect of the medium on the anharmonic character of the mechanical and electrical vibrations in the HCl molecule is qualitatively discussed.
The Absorption Spectra of Salts of Ytterbium in Crystals and Solutions Compared with Those of Cerium
Authors: Freed Simon , Mesirow Raymond J.
Published: January 2005

The absorption spectra of salts of ytterbium [the chloride YbCl3–6H2O, the acetate Yb(C2H3O2)3–4H2O and the ethylsulfate Yb(C2H5SO4)3–9H2O] were found to resemble those of cerium very closely, especially in their diffuseness even at low temperatures. This is in marked contrast with the sharp spectra of the other rare earths. The resemblance was anticipated on the supposition that the thirteen electrons in the 4f shell of Yb+++, one short of the maximum the shell can hold, would give rise to but one term 2F, the same term as the one electron of Ce+++ gives rise to. That is, activations aside from fine structure, are impossible when the thirteen electrons remain in the 4f shell. This prohibition is derived from the Pauli exclusion principle as it has been applied in gases. The lattice, however, may possibly modify the application of this principle. It was thought likely that the activated states of the ions in crystals would respond to any change in the application of the principle the lattice might impose. The spectra show that the principle holds for these ions in crystals in exactly the same way as it does in gases. Strong confirmation is obtained that the sharp spectra of the other rare earths consist of ``forbidden transitions,'' arising from a change in coupling among the electrons of the 4f shell.
The Line Absorption Spectrum of Gadolinium Ion in Crystals
Authors: Nutting G. C. , Spedding F. H.
Published: January 2005

With a view to determining the dependence upon crystal symmetry and chemical composition of the energy levels in a solid, the absorption spectrum of Gd+++ in a number of different synthetic crystals has been photographed at temperatures between 300° and 20°K. Using the external crystallographic symmetry as an indication of the probable degree of symmetry about the gadolinium ion in the lattice, it is established that the important factor in determining the splitting of the multiplets or the excited levels is the lattice symmetry and not the negative ion except insofar as the negative ion influences the crystal structure, for the spectra of monoclinic gadolinium chloride, bromide, sulfate and selenate are almost identical, but are very different from the spectra of the hexagonal formate, bromate and ethylsulfate. Gadolinium propionate and butyrate evidently have somewhat different internal symmetry from that of the other monoclinic crystals since their spectra resemble much more the spectrum of triclinic gadolinium acetate. The group of compounds including gadolinium trichloracetate, propionate, butyrate, isobutyrate and trichlorbutyrate is similar in that the spectra of all are weak, diffuse, and little resolved even at the temperature of liquid hydrogen. The presence or absence of water of crystallization affects the spectra only slightly. The positions of the multiplets, and the positions of the lines within the multiplets of anhydrous gadolinium formate are much the same as in the ethylsulfate and bromate enneahydrates. The phenomenon of highly discrete selective reflection in the ultraviolet region by three compounds has been observed. A discussion of the nature of the excited states of the gadolinium ion in crystals is presented.
Carbon Dioxide. The Heat Capacity and Vapor Pressure of the Solid. The Heat of Sublimation. Thermodynamic and Spectroscopic Values of the Entropy
Authors: Giauque W. F. , Egan C. J.
Published: January 2005

An apparatus for low temperature calorimetric and vapor pressure measurements on condensed gases is described. The heat capacity of solid carbon dioxide has been measured from 15 to 195°K. The heat of vaporization at the sublimation point, 194.67°K, was found to be 6030 cal./mole. The vapor pressure has been measured and the observations are closely represented by the equation: Solid carbon dioxide, 154 — 196°K; log10 P(int. cm Hg) = — (1354.210/T)+8.69903+0.0015880T—4.5107×10—6T2. The entropy of carbon dioxide gas has been calculated from the calorimetric data and the third law of thermodynamics to be 51.11 cal./deg. per mole at 298.1°K. This value is in excellent agreement with the value 51.07 cal./deg. per mole obtained from band spectrum data.
The Statistical Mechanics of Condensing Systems. I
Authors: Mayer Joseph E.
Published: January 2005

It is shown that for a system composed of N identical molecules with mutual potential energy, the assumption that the total potential energy can be expressed as the sum of that between pairs of molecules allows the derivation of simple, accurate formal equations for the thermodynamic properties of the system. Under certain conditions, generally fulfilled at low temperatures, the equations predict a region where the pressure and Gibb's free energy are independent of volume, the characteristic of condensing systems. The equations permit calculation of the Gibb's free energy of the liquid in equilibrium with the vapor and all the properties of the saturated vapor, but not the volume or volume dependence of the condensed phase.
The Statistical Mechanics of Condensing Systems. II
Authors: Mayer Joseph E. , Ackermann Philip G.
Published: January 2005

It is shown how the quantities entering into the equations for the thermodynamic functions of a saturated vapor, given in the previous article, may be calculated. It is necessary to evaluate certain integrals which enter into the final expressions as the terms of an (almost) infinite, but rapidly convergent series. The first two of these integrals have been evaluated with fair accuracy for a gas obeying the inverse seventh power law of force attraction. The third integral has been estimated. The coefficients with which these integrals enter into the final expression have also been estimated. The results of the calculation have been compared with the experimental values for CO2 and CH4. Specifically, the volume of the saturated vapor in units of the volume of the molecules, and the ratio (PV)/(RT) for the saturated vapor have been calculated on an arbitrary temperature scale. The agreement between the calculations and the experimental values is not unencouraging.
One-Electron Rotatory Power
Authors: Condon E. U. , Altar William , Eyring Henry
Published: January 2005

It is shown that a single electron moving in a field of suitable dissymmetry can give rise to optical rotatory power in a medium containing molecules of this type. This effect is called one-electron rotatory power and is in striking contrast to the models developed by Born, Oseen, Gray and others in which a dynamic coupling between several electronic oscillators is responsible for the rotatory power. The detailed calculations are carried out for the potential function, V=12(k1x2+k2y2+k3z2)+Axyz,which shows rotatory power both quantum mechanically and classically. Next it is shown how fields of this type may be adapted to an approximate description of the field in which the chromophoric electrons of a molecule move, the constants k1, k2, k3 and A being largely determined by the average charge on the different atoms of the molecule as found from additivity of dipole moments due to the bonds in the molecule. As illustrations of the theory absolute calculations are made for the contribution of the nitrite group to the rotatory power of methyl phenyl carbinol nitrite which agrees satisfactorily with experimental data, for the phenyl group contribution of the same molecule and for the hydroxyl group contribution in secondary butyl alcohol. In the latter two instances the theoretical values are much too small but as there is a great deal of freedom in the choice of the configuration because of free rotation these results merely indicate need for more detailed calculations. The general quantum-mechanical theory of circular dichroism is developed and a quantum-mechanical derivation of Natanson's rule is given. The quantum-mechanical definition of Kuhn's ``anisotropy factor'' is given and an alternative measure of the contribution of an absorption band to rotatory power called the rotatory strength is defined and discussed. It is shown that spin magnetic moments may generally be neglected in calculation of rotatory power owing to the weakness of spin-orbit interaction. Interpretation of experiments of Schwab, Rost and Rudolph on the catalytic dehydration of butyl alcohol on active quartz is discussed and kinetic arguments advanced to show how the relative configuration of quartz and butyl alcohol may be inferred from such data. The relation of one-electron rotatory power to known dipole moment and solvent effects on rotatory power is briefly discussed.
Absorbing and Reflecting Powers of Electrolytes in the Far Infrared
Authors: Cartwright C. Hawley
Published: January 2005

The absorbing and reflecting powers and the dispersion of different concentrations of HCl, LiCl, NaCl, KCl, KBr, LiI, KI, ZnI2, MgSO4, KOH and H2SO4 were measured in the spectral region of 50μ to 150μ. The results are discussed in terms of, (1) Maxwell's equations in which the inertia of the ions is included, (2) the influence of ions on the absorbing power of water molecules, (3) the electrical conductivity for high frequency electromagnetic fields, (4) the radius of ions, (5) the hydration of ions and (6) the validity of Stokes' law for the microscopic process involved.
A Method for Deriving Expressions for the First Partial Derivatives of Thermodynamic Functions
Authors: Lerman Frank
Published: January 2005

By this direct method, any first partial derivative of the thermodynamic functions may be readily resolved into terms of temperature, pressure, volume, and entropy, and of six basic forms of a mathematical quantity named a vired. These six basic vireds have been expressed in terms of the better known and more easily measurable thermodynamic quantities and therefore may be used in determining any of the first partial derivatives. This method stresses the interrelationship between the partial derivatives and is a distinct departure from Bridgman's method for obtaining expressions for the first derivatives by substitution from a list of 45 arbitrarily defined quantities which have been expressed in simpler terms.
Studies in the Autoxidation of Monolayers II. Catalysts and Inhibitors
Authors: Gee Geoffrey
Published: January 2005

An account is given of the effect of metallic catalysts and organic pro- and anti-oxygens added to the substrate on the rate of oxidation of monolayers of maleic anhydride α-elaeostearin. The catalytic effect depends both in direction and magnitude on the pH of the substrate. The results are discussed in the light of the autoxidation mechanism proposed in Part I, and a semi-quantitative kinetic treatment developed which accounts successfully for the principal features of the results.
Photochemical Studies. XXV. The Direct Photochemical Decomposition of Nitrous Oxide
Authors: Noyes W. Albert
Published: January 2005

The number of molecules of gas uncondensed by liquid air formed per quantum absorbed by nitrous oxide has been determined both in the presence and absence of mercury. At least part of the primary dissociation must be into nitrogen molecules and oxygen atoms. A mechanism consistent with the facts involves the subsequent reactions O+N2O=2NO and O+O=O2. However, it is impossible to state definitely that none of the primary dissociation is into nitric oxide molecules and nitrogen atoms. The weakness of the absorption suggests that the absorption is ``forbidden'' and it is possible that the nitrogen molecules and oxygen atoms are produced in their normal electronic states (with perhaps some vibrational energy in the nitrogen molecule).
Two Bands in the Infrared Spectrum of Formaldehyde
Authors: Ebers Earle S. , Nielsen Harald H.
Published: January 2005

Two infrared bands of the type arising from oscillations of the electric moment normal to the axis of symmetry have been measured under high dispersion and identified as the two oscillations which are at right angles to each other and which in Sutherland and Dennison's notation are v5 and v6. Their centers are respectively at 1278 cm-1 and 1165 cm-1. The anomalous spacing between the principal rotation lines is accounted for on the basis of an interaction between rotation and the two oscillations which are only slightly anisotropic.
Transfer of Rotational Energy in Molecular Collisions II. Exchange of Energy in Collisions Between Unexcited HgH and N2 Molecules
Authors: Rieke F. F.
Published: January 2005

It has been found that the intensity distribution in the HgH 4017 band excited by sensitized fluorescence in the mixture Hg+H2+N2 is influenced by the intensity of the primary light which excites the fluorescence. This observation may be interpreted as evidence of a very slow exchange of vibrational energy in collisions between N2 and HgH molecules in their normal electronic states. Two other possible causes of the phenomenon—self-reversal and reactions involving high energy Hg atoms formed by stepwise excitation—are ruled out by additional experiments.
Evidence for Halogen Films on Tungsten in the Surface Ionization of Potassium Halides
Authors: Hendricks J. O. , Phipps T. E. , Copley M. J.
Published: January 2005

Molecular rays of the potassium halides were directed in high vacuum against tungsten and tungsten-oxygen surfaces, and the positive ion current to a collector cylinder was measured as a function of the surface temperature. Degrees of ionization on oxygen-free surfaces were calculated upon the assumption that each halide molecule produced one positive ion on striking a tungsten-oxygen surface. The high temperature results on oxygen-free filaments (1800°-2380°K) were interpreted as indicating surface dissociation of the potassium halide molecule, followed by partial ionization of the potassium atom and by the escape of the halogen as an atom. In the approximate temperature range 1800–1600°K a progressive change in the surface, with decreasing temperature, toward a higher work function was observed. This change led to surfaces of constant high work function, which were interpreted as due to the formation of halogen layers on the tungsten.
The Absorption Coefficient of Nitrogen Pentoxide in the Ultraviolet and the Visible Absorption Spectrum of NO3
Authors: Jones Ernest J. , Wulf Oliver R.
Published: January 2005

Absorption spectrograms have been made of the gaseous system N2O5–O3 during the decomposition of the ozone and into the subsequent decomposition of the N2O5, placing these in time such that one was taken when the system consisted essentially of only N2O5 and oxygen. From such spectrograms as the last mentioned, the absorption coefficient, α10, of N2O5 has been measured over the wave-length range 3800–2850A. The value rises steadily from approximately 0.002 at the first wave-length to approximately 0.52 at 2850A. The absorption coefficient curve continues to rise to shorter wave-lengths and qualitative observations indicated no maximum as far as 2400A. No absorption which could be attributed to N2O5 could be observed in the 4500A region. Absorption spectrograms of NO3 in the visible are given. In a study using low dispersion of the influence of oxygen on the absorption spectrum of NO2, no noticeable effect was observed.
A Theory of Liquid Structure
Authors: Hirschfelder Joseph , Stevenson David , Eyring Henry
Published: January 2005

A simple model of the liquid is used to extend the equation of state previously obtained and to treat the process of fusion, viscous flow, and binary liquid systems. Our equation of state which applies to dense liquids has been fitted on to Happel's modification of van der Waals equation to give a single equation applicable over the entire range from gas to liquid. A liquid differs from a solid in that the surplus volume in one part of the liquid becomes available in another part without an activation energy appreciable as compared to kT. This communal sharing of volume gives rise to an entropy of fusion R modified, of course, if there are other structural changes. Other entropy changes arise from expansion, changes of librations into free rotations and from polymerization. Double molecules held together by van der Waals forces are considered quantitatively and used in the explanation of viscous flow and deviations of the equation of state at the critical point. An explicit expression is given for the osmotic pressure of a binary liquid mixture. ``Holes'' are used to complete the analogy between critical phenomena for a one component system and critical solution phenomena of binary liquids. In binary liquids the presence of a lower critical solution temperature above which two phases exist results from hydrogen (or analogous) bonds or bridges between unlike molecules which prevent free rotation. The critical mixing point coincides with the onset of free rotations which disrupt these bonds.
Bimolecular Association Reactions
Authors: Kassel Louis S.
Published: January 2005

The recent classical treatment of the rates of bimolecular association reactions proposed by Kimball is extended, and found to involve an essentially different dependence of reaction probability on vibrational energy initially present in the natural coordinates as kinetic energy from that present as potential energy. Since this difference can scarcely have any quantum-mechanical analog, it is concluded that a classical treatment cannot be satisfactory.
The Raman Spectra of the Methyl Alcohols, CH3OH, CH3OD, and CH2DOD
Authors: Halford J. O. , Anderson Leigh C. , Kissin G. H.
Published: January 2005

Measurements of the Raman spectra of CH3OH, CH3OD, and CH2DOD, produced by the mercury lines at 2536 and 4358A units, are analyzed to yield a provisional assignment of the fundamental frequencies. The significance of the character of the OH and OD bands to the problem of internal rotation is discussed. A new approximation to a potential constant for the C–O bond is presented.
The Structure of H3, H3+, and of H3—. IV
Authors: Stevenson David , Hirschfelder Joseph
Published: January 2005

In this paper, a direct calculation is made of the force constant for bending the nuclei in the triatomic hydrogen molecule, H3, and in the ion, H3+, from a straight line. The neutral molecule has lower energy when the atoms are in a line rather than in neighboring triangular configurations. The opposite is true for the positive ion. The quantum-mechanical variational method is used together with the most general eigenfunctions which can be compounded from 1s hydrogen-like orbitals. The polar-homopolar composition of these eigenfunctions and the effective nuclear charge are varied simultaneously to give the lowest energy. For H3, we obtain the force constant for bending, 15.88 kcal./radian2, and the corresponding vibration frequency for bending, 3.26×1013 sec.—1. These values agree well with those obtained by the semi-empirical scheme. The force constant for bending H3+ from a straight line is — 15.41 kcal./radian2. This negative value for the force constant indicates that the positive ion has lowest energy for triangular configurations, as predicted by Coulson. The energy of H3— is calculated for a linear symmetrical configuration. It is found that for reasonably small separations, H3— is unstable with respect to H2+H—. At large separations H— is attracted to H2 to form a loose cluster but a rough calculation of the equilibrium constant indicates that Concentration H3—/Concentration H—=0.2×pressure H2 in atmospheres. Thus at the low pressures which are used in the mass spectrograph, H3— could not be detected.
A Mechanical Analyzer for the Solution of Secular Equations and the Calculation of Molecular Vibration Frequencies
Authors: MacDougall D. P. , Wilson E. Bright
Published: January 2005

A set of coupled harmonic oscillators has been constructed, so designed that it can be used to solve the numerical secular equations occurring in the theory of the vibration of polyatomic molecules and in other problems. Each oscillator consists of a shaft with cross arms carrying weights to increase the moment of inertia and springs to provide restoring force. The unit is free to rotate about the axis of the shaft, except for the restoring force of the springs. The various units are connected to one another by additional springs. In operation the springs and weights are adjusted to values which represent the coefficients of the secular equation to be solved, the whole device is driven by an eccentric of variable speed, and the frequencies of resonance, representing the roots of the equation, are measured.
Phosphorus at High Temperatures and Pressures
Authors: Jacobs Robert B.
Published: January 2005

A detailed study of the transformations of the element phosphorus has been carried out at high hydrostatic pressures and at elevated temperatures. This has resulted in the discovery of a new modification of phosphorus, which is noncrystalline in structure and black in color. Its properties have been investigated to a certain extent. Some new calorimetric data are described which shed light on the question of the relative thermodynamic stabilities of this and the other forms of phosphorus.
A Study of Melting of the Mononitrophenols at High Pressure
Authors: Dow R. B. , Hibshman H. B.
Published: January 2005

The melting of the mononitrophenols has been studied over a pressure range of 4,000 kg/cm2 by separate application of a piston displacement and a new dynamic method. By the dynamic method, the procedure was to observe the sudden change of temperature difference as the nitrophenol underwent melting with change of pressure. Comparison of results obtained by the two methods indicate close agreement for the pressure-melting temperature data of ortho- and metanitrophenol which have not been studied previously over the present pressure range. Application of the dynamic method is compared briefly with that of the piston displacement method in respect to melting and polymorphic transitions of solids at high pressure.
Rotatory Dispersion of Configurationally Related Alkyl Azides
Authors: Levene P. A. , Rothen Alexandre
Published: January 2005

From the viewpoint of chemical behavior, the —N3 group may be regarded as a pseudohalogen. Like iodides, azides possess an absorption band in the near ultraviolet region. For both practical and theoretical reasons it was important to obtain information on the rotatory properties of the azides as compared with those of the corresponding halides. The correlation of the configurations of primary and secondary azides is discussed in this communication. From the analysis of the rotatory dispersion of the primary azides and halides it became evident that the partial rotations of the azido group and of the halogen atom may be of opposite sign in configurationally related substances. An unexpected observation was made with regard to the members of a homologous series of secondary azides, namely, the rotation in the visible region as well as the partial rotation of the azido group, changes sign on passing from the second member of the series to the third. A tentative explanation of the phenomenon is given. It was found that in all alkyl azides the absorption band at λ2880 is not anisotropic or at best, insignificantly so.
Linear or Edge Energy and Tension as Related to the Energy of Surface Formation and of Vaporization
Authors: Harkins William D.
Published: January 2005

The free energy of the edge of a lens of a nonvolatile oil on water is found by a consideration of the magnitude of the molecular energy involved to be very small, and of the order of 3 × 10-6 erg per cm. Thus the linear tension of the edge should be of the order of 3 × 10-6 dyne. The smallness of the energy does not indicate a lack of importance of the edge, since the molecular energy is higher than in the surface. Linear energy and the presence of edges are of importance in practically all solids, since these are in general built up of crystal grains, and are of special significance in certain biological systems. Equations which give the relation between the free, latent and ``total'' energy of the edge and the latent heat of vaporization, are presented.
Factors Influencing Rates of Reaction in Solution
Authors: Ogg R. A. , Rice O. K.
Published: January 2005

The factors which may influence the rates of reactions in solution have been classified and discussed with particular reference to the effect on A in the expression Ae-E/RT for the rate constant K. Means by which these different effects may be studied experimentally have been discussed. An explanation has been given of the tendency of A and E to change in the same direction, and of K and E to change in opposite directions, when comparison is made of the rate of a given unimolecular reaction in various solvents.
The Analysis of the Raman Spectra of Si2Cl6(l) and of Si2H6(g)
Authors: Stitt Fred , Yost Don M.
Published: January 2005

The Raman spectra of Si2H6(g) and of Si2Cl6(l) have been photographed. Polarization measurements of the stronger lines of Si2Cl6 have been made. From a consideration of the relations among the modes of vibration of similar molecules having different symmetry, the analysis of the observed lines is facilitated by a knowledge of the assignments of the fundamental frequencies of SiH4, HSiCl3 and BrSiCl3. A definite assignment is made for the three observed lines of Si2H6. A tentative assignment of the observed lines of Si2Cl6 is made and some evidence is presented for the existence of internal rotation in this molecule at room temperature.
Photochemical Reduction with X-Rays and Effects of Addition Agents
Authors: Clark George L. , Coe Wesley S.
Published: January 2005

Ceric sulfate solution was reduced by exposure to x-radiation. In order to follow this reaction a very accurate method was developed for the determination of ceric sulfate in dilute solutions by the use of orthophenanthroline indicator. The amount of reduction of ceric sulfate by x-rays was found to be practically independent of concentration. Reduction was shown to be directly proportional to time of exposure up to 50 percent and slightly less efficient beyond that point. Silver perchlorate and silver nitrate decreased the amount of reduction of ceric sulfate by x-rays. Mercuric nitrate and acetic acid increased the amount of reduction caused by x-rays. Curves are also presented to show the effect of changing the concentration of these addition agents. Indications are that the mercuric nitrate was truly a catalyst to the reduction of ceric sulfate by x-rays and that the acetic acid increased the amount of reduction by direct action on the ceric sulfate under the influence of x-rays. Perchloric and nitric acids increased the reduction of ceric sulfate appreciably but not to as great an extent as did Hg(NO3)2. Sodium nitrate, perchlorate and sulfate showed no effect. Various organic substances were tried and found to increase the reduction by varying amounts. Experiments were carried out with various combinations of the catalysts and inhibitors to determine their relative efficiencies. The reduction of potassium permanganate by x-rays proceeded to manganese dioxide for low acid concentrations and to manganous ion at higher acidity. The reaction was greater than for ceric sulfate but not as nearly proportional to dosage. The effect of addition agents was similar to that for ceric sulfate. X-rays did not produce the same reaction in solutions of uranyl sulfate-oxalic acid as does ultraviolet radiation. Solutions of potassium iodate were reduced by x-rays but to a less degree than ceric sulfate or potassium permanganate. Hydrogen peroxide was formed in samples during radiation but did not effect the potassium iodate. Solutions of potassium bromate were not reduced by x-rays but even larger amounts of hydrogen peroxide were formed. Calculations were made for: ions reduced per r unit absorbed, r units necessary for reduction of one equivalent, ions reduced per ion pair formed by x-rays, and calories of absorbed energy necessary for reduction of one equivalent, by two independent methods. A mechanism was proposed for the formation of hydrogen peroxide by x-rays in the presence of dissolved oxygen.
The Raman Spectra of Water, Aqueous Solutions and Ice
Authors: Hibben James H.
Published: January 2005

The Raman spectra of water at different temperatures, of aqueous solutions and of ice have been discussed in detail. Several low frequency shifts such as Δν̃ 150, 445 and the shift at 2170 are easily discernible if ultraviolet excitation is used. The first two of these vary markedly in intensity with temperature changes and are affected by some solutes. All three are present in ice at slightly displaced frequencies. At least some of these frequencies may be ascribed to the intermolecular influences. Whatever may be the mechanism of polymerization or association these results indicate that effectively such a state exists and is a function of environmental conditions.
Infrared Absorption Spectra of Four Grignard Solutions
Authors: Plum William Byrle
Published: January 2005

Absorption spectra are reported for twelve liquids: four typical Grignard solutions, and eight related substances, for the range 1.0 to 13 μ. Absorption frequencies at 784, 910, 4250 and possibly 1950 cm.—1 appear to be associated with compounds which contain magnesium. Possible origins of these frequencies are discussed.
The Reactions Between Atomic Deuterium and the Saturated Aliphatic Hydrocarbons
Authors: Trenner N. R. , Morikawa Kiyoshi , Taylor H. S.
Published: January 2005

The exchange reactions between atomic deuterium and methane, ethane, propane and butane have been studied in the range of temperatures, 0–300°C, in each case until significant amounts of exchange have been obtained. The extent of deuterization and the nature of the fragments produced have been examined by fractionation analysis and determination of the thermal conductivities of the fractions. From the temperatures at which the several interactions occur, approximate values for the activation energies of the individual processes have been deduced and these have been shown to conform with the mechanisms of reaction formulated. It has been indicated that deuterization of alkyl radicals in presence of atomic deuterium is a more rapid process than the deuterization of the saturated hydrocarbons. From the activation energies obtained, values for the bond energies CH3–H=108 kcal. and CH3–CH3=97.6 kcal. have been deduced. The discrepancies between these and other values have been emphasized. The uncertainty of the value of the steric factor in the activation energy calculations has been indicated and its influence on the results derived has been exhibited.
An Attempted Theory of Photosynthesis
Authors: Franck J. , Herzfeld K. F.
Published: January 2005

An attempt is made to explain quantitatively many observations described in the literature on the photosynthetic production of oxygen in its dependence on light intensity, time of irradiation, etc. Four photochemical steps and two dark reactions are assumed, in which among others, a peracid, formic acid and a peraldehyde occur. These are the same intermediate compounds as in auto-oxydation processes, so that the similarity between these two inverse processes is striking. Light saturation is explained by back chain reactions initiated by photolytical decomposition of the per-compounds. The agreement between observations and calculations is good. The picture gained for the photosynthesis of CO2 can be applied in the same way for that of plant acids but the plant acids can also be photooxidized in a reaction sensitized by chlorophyll.
The Exchange of Energy Between Organic Molecules and Solid Surfaces Part II. Accommodation Coefficients and Specific Heats of Paraffin Hydrocarbons and the Influence of Temperature on the Accommodation Coefficients (Including Argon) at Some 10—6 mm (Hg) Pressure
Authors: Beeck Otto
Published: January 2005

The investigation of the accommodation coefficients of the paraffin hydrocarbons and their relation to the specific heats reported in Part I of this series has been extended to various temperatures of the nickel surface and to various gas temperatures. The results are, within the experimental error of about 1 percent, in full agreement with the general formulae derived in Part I, by which the accommodation coefficients of the paraffins were related to their molecular weights and their specific heats. A complete summary of these relations is given at the end of this paper.