bluuebunny/crossref_metadata_2025 huggingface dataset:
Accommodation Coefficients on Gas Covered Platinum
Authors: Amdur I. , Jones Margaret McCormack , Pearlman H.
Published: January 2005

Accommodation coefficients on a platinum wire have been computed for five monatomic and five diatomic gases from Pirani gauge measurements at room temperature, 18.9° to 30.5°C. Through careful control of experimental conditions it was possible to apply exact theoretical relations for the effects of radiation, wire conduction, and free molecule conduction upon the temperature distribution along the gauge wire. For each of the gases the accommodation coefficient increases with pressure up to about 0.1 mm and then remains constant throughout the pressure range in which complete free molecule conduction exists, indicating the absence of complete gas saturation of the wire surface at the lower pressures. There is no detectable temperature coefficient in the small interval in which measurements were made. At room temperature the mean accommodation coefficients on a completely gas covered platinum wire are: helium, 0.403±0.001; neon, 0.700±0.002; argon, 0.847±0.002; krypton, 0.844±0.002; xenon, 0.858±0.002; hydrogen, 0.312±0.001; deuterium, 0.393±0.001; nitrogen, 0.769±0.002; carbon monoxide, 0.772±0.002; oxygen, 0.782±0.002.
Molecular Constants and Chemical Theories I. The Parachor (Molecular Volume)
Authors: Samuel R.
Published: January 2005

Theories of valency are based on physical properties of molecules, most of which are expressed in terms of so-called ``additive molecular constants.'' Dipole moments, molecular volumes, bond distance, energies of formation, etc., belong to this class. The following paper intends to show that such constants are capable of being consistently interpreted in various entirely different ways. Hence a number of entirely equivalent but different and discordant theories of valency are possible, leading, for instance, to classical or to resonance structures of inorganic molecules. The choice between them therefore is arbitrary and not due to necessity. In the following part, I, one of these additive molecular constants, namely, the molecular volume in terms of the parachor, is studied in detail. The existence of coordinate types of covalent linkage having been ruled out by new experimental evidence for many inorganic first-order molecules formed by a definite central atom (Section 1), a new set of atomic parachors is calculated on the basis of the classical formulae of chemistry (Section 2). Instead of resorting to different types of bonds and their respective parachor constants, it ascribes different constants to the same atom in different valence states (Section 3). The contributions of the constituent atoms to the volume of the covalent molecule thus calculated bear a close relation to their atomic numbers and to their ionization potentials (Section 4). The new atomic parachors account for such molecules as N2, O2, N2O, CO, CO2, SO2, which earlier had to be considered as anomalous, and also give the correct structure of the azides. However, as the molecular volume apparently can be separated into atomic contributions according to entirely different concepts of valency, the parachor (i.e., the molecular volume) is an example of an additive molecular constant which is unable to distinguish between different possible structures of a molecule or the different conflicting chemical theories on which they are based.
Molecular Constants and Chemical Theories II. Additive Molecular Constants and Chemical Structures
Authors: Samuel R.
Published: January 2005

All additive molecular constants, besides parachor and molecular refractivities (Part I), in particular also dipole moments, bond distances, and energies of formation (or bond energies) may be separated into individual (atomic or bond) contributions according to different proposed structures of a covalent molecule or different chemical theories on which these structures are based. Such constants do not therefore possess diagnostic qualities as to the nature of different covalent bonds, and different theories or concepts based on them, by necessity are inconclusive. A number of standard examples of molecules formed by a marked central atom are considered, which often are assumed to establish the existence of a second variety of covalent linkage, i.e., coordinate bonds, or its wave mechanical counterpart, i.e., enhanced resonance of covalent and ionic (or other) forms. For all of them, all the above molecular constants are in perfect agreement also with the older classical formulae, including those of pentacovalent nitrogen. Again wave mechanics does not offer any objections but is in full accord with these classical structures. While a decision between different sets of formulae and concepts cannot be reached by means of any of these additive molecular constants, spectroscopical evidence is leading farther and appears to favor the older classical system and its underlying concepts.
The Mechanism of Copolymerization
Authors: Alfrey Turner , Goldfinger G.
Published: January 2005

The mechanism of catalytic copolymerization of two monomers A and B is treated with the the aid of steady state approximation. Two initiation and two termination rates are assumed, one for each monomer. Four propagation rates are considered, corresponding to the four possibilities of addition, namely, addition of monomer A to a chain ending in A* or to a chain ending in B* and addition of monomer B to a chain ending in A* or to a chain ending in B*. Over-all rate and number average molecular weight are calculated. The composition of the polymer and the number distribution curves of groups of submolecules a and of submolecules b are calculated as functions of the monomer composition and two rate constant ratios. These last results are of general character and independent of the nature of the initiation and termination processes provided that the average degree of polymerization is ``high.''
Theory of Chain Copolymerization Reactions
Authors: Simha Robert , Branson Herman
Published: January 2005

The kinetics of chain copolymerizations is developed for reactions consisting of three steps: first, an activation of stable monomer; second, a growth of activated polymer radical by means of monomer addition; third, a stabilization of the growing chains by (a) monomer addition, (b) by means of growing polymer [Eq. (1)]. The existence of a steady state in respect to the concentration of growing chains beyond the induction period is assumed. The rate constants of growth and termination will in general depend upon the individual composition and upon the nature of the activated chain end. Equations for the rate of change of mole ratio z of the two monomer species are developed in terms of mean rates of growth and termination obtained by averaging the actual rates over the distribution of growing polymer [(4), (4a), (4′)]. The equilibrium conditions lead to a set of difference equations for this distribution [(5), (5′)]. It is investigated whether the solution and results derived therefrom are of a form which permits a determination of the dependence of the rate constants for growth and termination upon the composition of the polymer molecule (6). In addition, the influence of the type of active chain end involved on over-all rate and size distribution is considered by introducing four constants for propagation and termination, respectively, according to the four possibilities A — A, A — B, B — A, B — B [(6a), (7), (4b), (4b′)], but independent of chain composition. Various special cases according to the relative magnitude of the rates for the two reactants are presented. Experimentally it is difficult to distinguish on the basis of kinetic data between the foregoing mechanism and one in which the rates of growth (and termination) for each of the two kinds of monomer depend solely upon the nature of the monomer molecule added and are independent of the nature of the active chain end [(4c), (4c′), (4c″)]. Relations are derived for the molecular size distribution, the inhomogeneity of the copolymer mixture in regard to composition, the average molecular weight, and the average composition of copolymer as function of the composition of the monomer residue [(8a), (8a′), (9a), (10)]. The importance of these results for soluble and insoluble copolymers and for the theory of gel formation in vinyl-divinyl type polymers is pointed out.
The Crystal Structure of Ni4Mo
Authors: Harker David
Published: January 2005

A nickel-molybdenum alloy containing about 20 atom percent of molybdenum exists above 900°C as a cubic close-packed structure. If this alloy is quenched and then held at temperatures below 840°C, an ordering reaction occurs which results in a slight tetragonal distortion of the cubic structure. This ordered structure requires for its description a tetragonal cell with 2.5 times the volume of the distorted face-centered cubic cell. The completely ordered structure can be described analytically as follows: space group: C4h5—I4/m; dimensions of unit cell: a0=5.720A, c0=3.564A, c/a=0.6231; atomic positions: 2 Mo in 2(a), 8 Ni in 8(h), x=0.200. y=0.400.
The Dissociation of Ammonium Chloride
Authors: Stephenson C. C.
Published: January 2005

Two values for the standard free energy of dissociation of ammonium chloride into ammonia and hydrogen chloride, calculated by two independent paths, are 21,860 cal. and 21,780 cal. at 298.1°K. The good agreement serves as additional evidence for the complete dissociation of ammonium chloride in the vapor phase. The corresponding values calculated for ΔH at 298.1 are 42,160 and 42,260 cal. Two independent values for the standard entropy of the aqueous ammonium ion at 298.1°K derived from these data are 26.5 and 27.1 cal. mole−1 deg.−1.
The Spectrum of Deuteroacetone in the Vacuum Ultraviolet A Comparison with the Spectrum of Acetone
Authors: Lawson Martha , Duncan A. B. F.
Published: January 2005

The spectrum of acetone-d6 of over 90 percent purity has been photographed in the region 2000–1300A, with a dispersion of 4.14A per mm. Data for the transition at about 51,000 cm−1 are presented together with new data on acetone in the same region. A discussion of the normal state of the acetones is given, and an analysis is made of the electronic spectra. It is shown that no vibrational frequency near 1200 cm−1 appears in the excited state of acetone-d6 and that this frequency in acetone cannot be ascribed to the C–O vibration.
The Dissociation of H2O into H+OH
Authors: Dwyer R. J. , Oldenberg O.
Published: January 2005

The energy of dissociation of H2O into H+OH was measured by an experiment developed from the method of Bonhoeffer and Reichardt. A spectrograph of high resolving power served for the measurement of the intensity of the absorption spectrum of OH in a heated mixture of water vapor and oxygen. The result (for 0°K) was H+OH→H2O−118.2±0.7 kcal. and O+H→OH−100.1±0.9 kcal. The probabilities of transition of the lines of the OH band were recomputed.
The Reaction of Hydrogen Atoms with Acetylene
Authors: LeRoy D. J. , Steacie E. W. R.
Published: January 2005

An investigation has been made of the reaction between hydrogen atoms and acetylene. With the large hydrogen atom concentrations produced in the discharge tube, catalytic recombination of hydrogen atoms occurs but no hydrogenated products could be detected. With small hydrogen atom concentrations resulting from mercury photosensitization, ethane and butane are produced together with a partially hydrogenated polymer. The results are discussed from the point of view of the elementary reactions involved and it is concluded that ethyl and vinyl radicals play an important part in the reaction.
A Molecular Theory of the Viscoelastic Behavior of an Amorphous Linear Polymer
Authors: Alfrey T.
Published: January 2005

The kinetic theory of rubber elasticity is extended in two respects. First, the distribution of relative displacements of every chain atom is considered, not merely the distribution of relative chain-end displacements. Second, the rate of approach to elastic equilibrium, as well as the equilibrium itself, is considered. As a first approximation, it is predicted that a linear amorphous polymer will possess a distribution of elastic retardation times of the form J(τ)dτ=(C ln τ — D)d ln τ, where C and D are constants characteristic of the material.
Molecular Constants and Chemical Theories III. Bond Moments of Higher Valence States
Authors: Samuel R.
Published: January 2005

In continuation of Part I and Part II of this paper, bond moments are calculated for such molecules as are formed by a marked central atom in a higher state of valency. Again the classical structures are taken as a basis. The bond moments are additive in the same molecule and unchanged from molecule to molecule as long as the multiplicity of the bond and the state of valency of either atom remain the same. This treatment on the basis of classical formulae makes possible the simple and straightforward calculation of the total moments of a considerable number of molecules formed by pentavalent nitrogen (azoxybenzenes, N-ethers of nitrobenzophenoneoximes), for which no other such calculation has been possible so far. Observable facts of dipole measurements, therefore, are at least as well represented by the classical structures and their underlying concepts, as by any other theory of the covalent bond. Hence, dipole moments do not provide any evidence of the existence of such linkages as a semipolar double bond or its wave-mechanical equivalent, i.e., enhanced resonance with ionic parent structures.
Theory of the Diffuse Double Layer in Liquids
Authors: Anderson George M.
Published: January 2005

The theory of the diffuse double layer in liquids, as developed by Jaffe for plane, parallel, blocking electrodes, is extended to include the ionic charges as boundary conditions and the effects of a surplus of one ion. Dissociation and recombination effects are included. The results are expressed in terms of elliptic integrals and Jacobian elliptic functions. It is found that the electrically neutral condition can be divided into three regions designated field limited dielectrics, charge limited dielectrics, and electrolytes. Approximations of the exact expressions are developed for each region.
Truncated Reaction Operators
Authors: Meath William J. , Sando Kenneth M. , Goscinski S. Osvaldo , Hirschfelder Joseph O.
Published: January 2005

The reaction operator formulation for the exact solution of the Schrödinger equation is used with a truncated basis set to obtain approximate solutions. The relationship between this truncated reaction operator formalism and the Rayleigh—Ritz variational method is emphasized and shown explicitly. The truncated reaction operator and its matrix elements are discussed in general; computed and discussed for a simple example, the helium atom, using a three-membered basis set. It is shown that the reaction operator can be replaced by a function which we call the ``effective'' perturbation potential Veff. Approximations to Veff are computed for the ground state of helium. This function has fundamental significance and lends itself to accurate empiricism.
Work Function Change on Monolayer Adsorption
Authors: Macdonald J. Ross , Barlow C. A.
Published: January 2005

A self-consistent treatment is presented of the change in work function, or surface potential, produced by the adsorption of an immobile or mobile regular array of adsorbate entities on a plane (usually conducting) adsorbing surface. The adsorbed entities may be polarizable atoms, ions, or molecules, and the molecules and ions may have orientable permanent dipole moments, not assumed fixed in direction. The depolarizing field at a given adsorbed element arising from the total polarization of all its surrounding elements is taken into account in all cases, as is the possible presence of an average charge on the adsorbing surface. A distinction is introduced between the ``natural'' field polarizing a single adsorbate entity and the similar effective field leading to some time-average permanent dipole polarization. General formulas for surface potential in terms of surface charge and surface coverage are derived for all cases and compared with earlier, less general treatments of the same cases. The results are applied to electrolyte double-layer measurements and surface-potential determinations.
Exchange Reactions with Deuterium I. Deuterium and Hydrogen Chloride
Authors: Cross Paul C. , Leighton Philip A.
Published: January 2005

An apparatus for measuring exchange equilibria and rates of exchange of molecular deuterium with hydrogen containing compounds is described. The gas density balance is used to analyze the hydrogen-deuterium mixtures. Results on the equilibria H2+2DCl = D2+2HCl, H2+DCl = HD+HCl are reported which check the theoretical values to within the limits of the experimental errors.
The Viscosity of Deuterium Oxide and Its Mixtures with Water at 25°C
Authors: Jones Grinnell , Fornwalt Holmes J.
Published: January 2005

The viscosity, η, of 97.6 percent deuterium oxide and six more dilute mixtures with water, as well as that of nearly pure protium oxide, has been determined by comparison with ordinary water, and found to be almost but not quite a linear function of the specific gravity. The relative fluidity, Φ, has been related to the density by an equation of the type φ=1/η=1+A(Δs)+B(Δs)2, where (Δs) is the increase in the specific gravity over ordinary water. This equation has been found valid to 0.006 percent over the entire concentration range. Bingham's equation concerning the law of additive fluidities in binary systems, and containing but one arbitrary constant, has been tested and found valid to 0.01 percent.
Determination of the Radium Content of Rocks
Authors: Urry Wm. D.
Published: January 2005

The determination of the age of common rocks by the ``helium method'' necessitates accurate measurements of the radium content. The method of compensating the background by the use of two opposed ionization chambers is applied to radium determinations and the apparatus has an observational limit of 5.5×10—14×n—½ g radium for n hourly readings. With the thorium content determined as in the preceding article a summary of results for a suite of rocks from a single horizon and the present status of a geological time scale is given.
Rotatory Dispersion of Aliphatic Aldehydes
Authors: Levene P. A. , Rothen Alexandre
Published: January 2005

Rotatory dispersion curves of configurationally related aldehydes of the type     CH3     |H–C–(CH2)nC=O–H     |    C2H5(n being equal to 0, 1, 2, or 3) have been determined in the visible and the ultraviolet regions of the spectrum. Their analysis has shown first, that the band of the aldehydic group at λ2950 is rotatory active and that the sign of its contribution in the first member (n=0) is opposite to that of the higher members and second, that the magnitude of that contribution varies periodically with the number of carbon atoms located between the aldehydic group and the asymmetric carbon atom.
Studies on Glass XII. Some New Heat Capacity Data for Organic Glasses. The Entropy and Free Energy of dl-Lactic Acid
Authors: Parks George S. , Thomas S. Benson , Light Donald W.
Published: January 2005

Heat capacity measurements by the Nernst method have been made upon samples of secondary butyl alcohol and 3-methylhexane in the glassy and liquid condition and upon a sample of dl-lactic acid (1) in an incompletely crystallized state, (2) in the form of an acid glass and liquid, and (3) in the form of a mixed glass and liquid. From these results the specific heats and heat of fusion of pure crystalline dl-lactic acid also have been derived. The data for the several glasses and undercooled liquids show a rapid rise from the heat capacity characteristic of a crystalline solid to that for the liquid state within a transition region of about 10° and the nature of this transition region has been discussed. A calculation of the molal entropy and free energy of formation of liquid dl-lactic acid at 298.1°K yields 45.9 (±1.0) e.u. and —124,300±(2300) cal., respectively.
Studies on Glass XIII. Glass Formation by a Hydrocarbon Polymer
Authors: Ferry John D. , Parks George S.
Published: January 2005

Polyisobutylene, with an average molecular weight of about 4900, is at room temperature a highly viscous liquid. When cooled, it has been found to form a glass, with the same transitions in thermal properties characteristic in the vitrification of substances of low molecular weight. The heat capacity of polyisobutylene has been measured from 118°K to 295°K. It increases by 32 percent between 192°K and 202°K. The thermal expansion coefficient of polyisobutylene has been measured from 160°K to 300°K. It increases by 200 percent between 185°K and 205°K. The mean temperature of transition corresponds to a viscosity of about 1013 poises, in agreement with a rule observed generally for glass-forming materials. The factors on which the transition temperature depends are discussed.
The Kinetics of the Oxidation of Gaseous Hydrocarbons III. The Oxidation of Acetylene
Authors: Steacie E. W. R. , McDonald R. D.
Published: January 2005

An investigation of the kinetics of the oxidation of gaseous acetylene has been made by the static method. The results show marked irregularities due to variations in the surface. The rate of the reaction is given by −(d/dt)(C2H2)=K(C2H2)2.7/(O2)0·1 when oxygen is in excess. In a packed bulb the order is diminished to about 1.4. Packing decreases the rate at high pressures and has little effect at low pressures. In an empty vessel the CO/CO2 ratio of the products is independent of the pressure. Packing decreases this ratio, and it further decreases rapidly with diminishing pressure. The apparent heat of activation of the reaction is about 35,000 calories. The addition of glyoxal to the reaction mixture causes no change in the rate of the reaction, while formaldehyde causes a marked retardation. The products of the reaction are discussed in the light of recent work on the oxidation and decomposition of glyoxal.
Resonance Fluorescence of Benzene. II
Authors: Cuthbertson G. R. , Kistiakowsky G. B.
Published: January 2005

Further study of the resonance fluorescence of benzene with an improved technique is described and the analysis of the spectrum given some time ago by Kistiakowsky and Nelles is amplified and corrected. The new assignment shows that, upon absorption of the 2536A mercury line, only the changes of the quantum number of one (ν1; ω = 990 cm—1) vibration of the nonexcited benzene molecule are unrestricted in fluorescence. In other vibrations the changes of the quantum numbers are not larger than unity (or two when required by selection rules). This interpretation of the resonance spectrum accounts for most of the line groups measured on the new plates. Five frequencies, besides ν1, or their multiples can be tentatively identified; they are: 432; 791; 1542; 2557 and 3174 cm—1. The fluorescence of hexadeuterobenzene has also been studied and the spectrum interpreted in the same manner but not as completely as that of benzene. The frequencies observed are: 944 (Δν unrestricted); 2460. The quenching of the resonance fluorescence of benzene has been investigated with five different gases. This fluorescence is quenched by being changed into high pressure fluorescence. There is very little, if any, loss of electronic excitation energy by benzene molecules on collisions. The quenching action is quite unspecific and appears to increase as the kinetic cross section of the foreign gas molecules. Some new high pressure fluorescence bands have been observed in benzene in the presence of foreign gases. These bands support V. Henri's analysis of the absorption spectrum as consisting of two close electronic levels of the excited molecule. Attempts to excite resonance fluorescence of benzene derivatives have, on the whole, been unsuccessful. Fluorobenzene and toluene, even at 0.01 mm pressure, emit spectra which, by using a spectrograph with a resolving power of better than 25,000, appear nearly continuous. Other derivatives tried have too little fluorescence to study it at low pressures.
The Infrared Absorption Spectra of H2S, HDS and D2S
Authors: Bailey C. R. , Thompson J. W. , Hale J. B.
Published: January 2005

The infrared spectra of H2S, HDS and D2S have been examined up to 15 μ with a monochromating prism spectrometer, and the results compared with the Raman spectra. The fundamental frequencies have been assigned with reasonable certainty, and a calculation has been made of the frequencies corresponding to infinitesimal amplitude. The cruder methods of the vibrational-rotational spectrum suggest a vertical angle of 110°, as compared with 92° obtained previously from a rotational analysis.
Kinetics of OH Radicals as Determined by Their Absorption Spectrum I. The Electric Discharge Through Water Vapor
Authors: Frost A. A. , Oldenberg O.
Published: January 2005

(1) The order of the reaction causing the rapid disappearance of OH radicals after interrupting an electric discharge through H2O vapor is measured by photometry of absorption spectra taken in snapshots. (2) These spectra are taken in time intervals of a few tenths of a second with a 21-foot grating and rotating interrupter and sector. (3) Relative concentrations of OH radicals are derived by comparing intensities of rotational lines within one branch of the 0→0 band of OH, the relative intensities being given by the theory of Hill and Van Vleck. (4) The decay of OH with time for various H2O pressures and addition of He is given in diagrams and a table of rate constants. (5) A discussion of the kinetics leads to triple collisions consuming OH. (6) KCl covering the surface of the absorption tube materially increases the rate of the reaction. (7) The absorption spectrum of H2O2 investigated simultaneously showed that no appreciable H2O2 is formed in the reaction. (8) In the processes consuming OH radicals after interrupting the discharge through H2O vapor in clean glass tubes, the triple collision H+OH+M→H2O+M plays a predominant part.
The Diamagnetic Anisotropy of Aromatic Molecules
Authors: Pauling Linus
Published: January 2005

Values of the diamagnetic anisotropy of benzene and other aromatic hydrocarbon molecules are calculated on the basis of the assumption that the pz electrons (one per aromatic carbon atom) are free to move from carbon atom to adjacent carbon atom under the influence of the impressed fields. When combined with the assumed values for the contributions of the other electrons (-2.0×10-6 for hydrogen, -4.5×10-6 for aromatic carbon, -6.0×10-6 for aliphatic carbon) these lead to principal diamagnetic susceptibilities of molecules in approximate agreement with the available experimental data. The diamagnetic anisotropy of graphite is also discussed.
The Exchange of Energy Between Organic Molecules and Solid Surfaces Part I. Accommodation Coefficients and Specific Heats of Hydrocarbon Molecules
Authors: Beeck Otto
Published: January 2005

A molecular beam method primarily devised for the investigation of heterogeneous thermal decomposition of hydrocarbon-molecules (to be published later) was used to determine the accommodation coefficients of various hydrocarbon molecules at 20°C on an ordinarily clean nickel surface at 140°C and at pressures in the region of 10-6 mm Hg. The absolute values of the accommodation coefficients were obtained by relative measurements with the help of the following simple relation that was found to exist for paraffin hydrocarbons between the accommodation coefficient α, the specific heat per mole at constant pressure for the ideal gas state Cv0, and the molecular weight M,α(Cv0+R/2)/M=constant=0.352,where R is the gas constant per mole. This equation supports a further relation which can be set up for the mean specific heat between 20° and 140°C for the paraffins by using a few reliable Cv0 values: Cv0 = 0.352M +1.80. A combination of both relations gives the simple equation for α of the paraffins: α=c1M/(c1M+c2),where c1 = 0.352 and c2 = 1.80+R/2. The accommodation coefficient for hydrogen was found to be 0.310, in excellent agreement with earlier experimental values. The accommodation coefficients of ethane and ethylene whose specific heats are known from normal frequencies were found to be equal within a few tenths of a percent; acetylene was found to be 3 percent lower. Specific heats have been calculated for paraffin gases and vapors up to n-heptane by a combination of the results of this work and the specific heat of ethane from the normal frequencies. The specific heats are given to 300°C. Under the assumption of equal accommodation coefficients for paraffins and corresponding olefines based on the accommodation coefficient measurements of ethane and ethylene and on their specific heats, specific heats are given for propylene and n- and isobutylene at 300°C. It was found that the absolute difference between the specific heats of a paraffin and the corresponding olefine decreases with the chain length. The Cv0 values of the following pairs were found to be equal within the experimental error of one percent: n- and isobutane, n- and isobutylene, methyl acetylene and allene. Approximate values for the mean specific heats between 20° and 140 C are given for methyl acetylene and allene. A discussion is given of the relationship of the present work to spectroscopic work in the field.
Absorption Spectra of the Vapors of Twelve Alcohols and of Nitric Acid in the Region of the O–H Harmonic Band at λ9500
Authors: Badger Richard M. , Bauer Simon H.
Published: January 2005

The absorption spectra of the vapors of twelve alcohols and of nitric acid have been investigated by photographic methods in the region λλ9450–9850. In each case a strong harmonic band of the O–H vibration was found. In the primary alcohols and in o-chlor phenol the O–H vibration was found to split into two components, a possible explanation for which is briefly discussed. In the bands of certain other substances a considerable complexity of structure was observed which is attributed either to a free rotation or a torsional vibration of the hydroxyl hydrogen with respect to the remainder of the molecule. Systematic shifts in the frequency of the O–H vibration with changes in the structure of the alcohol molecule were found.
The Absolute Rate of a Chemical Reaction: The Formal Thermodynamic Treatment
Authors: Rodebush W. H.
Published: January 2005

In order to assign a definite value to the entropy of activation, it is necessary to make definite assumptions as to the topography of the energy surface traversed by the reacting system. When this is done, the entropy of activation becomes the difference between the entropy of the average molecule and the entropy of the activated complex at the steady state concentration required for unit rate of reaction. The racemization of diphenyl derivatives is considered as a special case of unimolecular reaction where hv≪kT.
The Ultraviolet Absorption Spectra of Simple Hydrocarbons I. n-Heptene-3 and Tetramethylethylene
Authors: Carr Emma P. , Walker Margery K.
Published: January 2005

The ultraviolet absorption spectra of n-heptene-3 and tetramethylethylene were measured in liquid and hexane solution phase, between 4000A and 2100A and in vapor phase between 2300A and 1500A. Curves showing the logarithm of the molecular extinction coefficient as a function of the wave number are given for the measurements in the quartz region and tables giving the regions of absorption together with the wave-lengths of the centers of bands for the measurements with the fluorite vacuum spectrograph. Comparison with earlier work shows the progressive shift toward the visible of the absorption bands in the Schumann region as the hydrogen atoms of ethylene are replaced by alkyl groups, and the parallelism between the spectra of different hydrocarbons having the same configuration with respect to the double bond.
The Ultraviolet Absorption Spectra of Simple Hydrocarbons II. In Liquid and Solution Phase
Authors: Carr Emma P. , Walter Gertrude F.
Published: January 2005

Molecular extinction coefficients for twelve olefine hydrocarbons have been determined between λ = 3300A and 2100A and are given in the form of curves showing the logarithm of the extinction coefficient as a function of the wave number. The beginning of absorption, as measured by log ε = — 2.0, is quite characteristic of the number of alkyl groups bound to the carbon atoms of the double bond and is only very slightly affected by the nature of the alkyl group.
Vibration Spectra and Molecular Structure I. General Remarks and a Study of the Spectrum of the OH Group
Authors: Barnes R. B. , Bonner L. G. , Condon E. U.
Published: January 2005

A brief survey is given of the ideas underlying the interpretation of molecular vibration spectra in connection with molecular structure problems. This is followed by a discussion of the reasons for the appearance or nonappearance in the spectrum of the characteristic frequency at 3400 cm—1 for various molecules containing the OH group. In certain alcohols and glycols this frequency has not been reported in the Raman effect, but it is concluded that this must be due to experimental difficulties. In the carboxylic acids, on the other hand, as well as in certain aromatic compounds containing OH, the characteristic frequency is definitely absent from both the Raman and infrared spectra, and the role of the hydrogen bond in association and chelation is discussed in connection with these cases.
Normal Vibration Frequencies of the Molecule XYZ3
Authors: Rosenthal Jenny E. , Voge H. H.
Published: January 2005

A very general expression is set up for the potential energy of the tetrahedral molecule XYZ3. The normal vibration frequencies are given as functions of the constants in this expression. The equation for the parallel frequencies is shown to be essentially independent of the shape of the tetrahedron, while for the perpendicular case the two angles determining the molecular configuration must be taken into account. Connections are given between the general potential energy constants and the constants for the special forces used by Dennison and Sutherland.
The Infrared Absorption Spectra of Mixtures of Acetone and Water
Authors: Williams Dudley , Plyler E. K.
Published: January 2005

A study of the infrared absorption spectra of acetone containing water revealed an associational band in the region 2.7μ. This band was studied for concentrations of water varying from 0.5 percent to 70 percent by weight. The intensity of the associational band increased with the water content of the mixture. When the water content was large, the 3μ water band overlapped the associational band. Absorption spectra were obtained for ten mixtures. It was found that concentrations of water as low as 0.1 percent could be detected by the presence of this band.
The Infrared Absorption Spectra of Deuteroxide Solutions in Deuterium Oxide
Authors: Plyler E. K. , Williams Dudley
Published: January 2005

The infrared aborption spectra of deuterium oxide and deuteroxide solutions in D2O have been measured in the region from 2.5μ to 9μ. Also solutions of Na2CO3 and K2CO3 in D2O have been studied in the same region. The spectra of deuterium oxide possess strong bands at 4.0μ and 8.2μ and the results agree with those of other workers. The absorption at 4.0μ is probably composed of several overlapping bands. Intense bands were observed in the NaOD solutions at 3.1μ, 4.95μ and 7.1μ. The hydrolyzing salts in D2O gave rise to bands in these regions, but with some shifts in wave-length. The changes in the spectra were probably caused by the absorption of the CO3 ion and D2CO3 which was formed in the solution. The relation of the absorption of NaOD in D2O to the absorption of NaOH in H2O is discussed. It is concluded that the OD ion has an absorption band at 3.1μ and that the bands at 4.95μ and 7.1μ are produced by hydration.
The Raman Spectrum of Tetraethyl Silane. Vibrational Resonance of Tetraalkyls
Authors: Anderson Thomas F.
Published: January 2005

The Raman spectrum of tetraethyl silane is reported. Assignments of frequencies for this compound and for other tetraalkyls are made. An analysis of resonance between vibrations v1+v2 and v3 explains the presence of extra lines which appear in the Raman spectra of each of these compounds. Resonance between frequencies 2v2 and v4 explains the presence of two additional lines observed in Si(C2H5)4. Resonance between ethyl vibrations in Si(C2H5)4 and in Pb(C2H5)4 accounts for a split in the frequencies characteristic of the ethyl group. First-order perturbation calculations of the observed resonance effects are given in some detail.
Studies on Glass XIV. Note on the Compressibility of Glucose Glass
Authors: Lyman John C. , Parks George S.
Published: January 2005

The coefficient of cubical compressibility of glucose glass at 24°C has been found to be 18.8 (10—6) atmos.—1 for the pressure range 7–25 atmos. The relatively large intermolecular forces in polyhydroxy substances, such as glassy glucose and liquid glycerol, are indicated by a comparison of the compressibility and expansion coefficients for these and other typical organic compounds.
The Kinetics of the Decomposition of Ethyl Ether at High Pressures
Authors: Steacie E. W. R. , Hatcher W. H. , Rosenberg S.
Published: January 2005

The decomposition of diethyl ether has been investigated with considerable accuracy at pressures up to 260 atmospheres at 426°C. The results confirm the previous approximate values found by Steacie and Solomon. The rate of the reaction is still increasing at the highest pressures investigated. The results may be qualitatively explained by the Rice-Herzfeld mechanism, and support the idea that the reaction is not a simple unimolecular change.
The Distribution of Molecules in a Model Liquid
Authors: Morrell W. E. , Hildebrand J. H.
Published: January 2005

A three-dimensional model molecular assemblage has been constructed permitting a determination of the relative frequency of occurrence of the varying intermolecular distances. The model simulates the expansive effect of temperature. A good approximation is obtained to the distribution of molecules in liquid mercury determined by Menke by the aid of x-ray diffraction.
X-Ray Diffraction Study of Liquid Sodium
Authors: Tarasov L. P. , Warren B. E.
Published: January 2005

The x-ray scattering curve for liquid sodium is obtained photographically with Mo Kα radiation, monochromatized by reflection from rocksalt. By a Fourier analysis of the corrected scattering curve, one obtains directly the radial distribution of atoms about any atom in the liquid. The distribution curve shows a first concentration at about 4.0A, followed by a dip at 5.0A, and a second concentration at about 7A. The significance of the curve as giving a picture of a simple monatomic liquid is discussed.
Studies on the Decomposition of Azomethane I. Description of the Apparatus
Authors: Sickman Darrell V. , Rice O. K.
Published: January 2005

An apparatus for measuring the rates of gaseous reactions in the presence of large excesses of inert gases, using an adaptation of the Huygens manometer as the pressure measuring device, is described.
Studies on the Decomposition of Azomethane II. Pure Azomethane and Azomethane in the Presence of Helium
Authors: Rice O. K. , Sickman Darrell V.
Published: January 2005

In §§1–5 data on the decomposition of azomethane are presented and compared with those obtained by Ramsperger, with which they do not entirely agree. In §6 the possible effect of self-heating of the reacting gas is considered. In §7 some modifications in the theory of unimolecular reactions, called for if only partial deactivation occurs at collision, are discussed and found not to be of importance. The theory is applied to the present data and the pressure dependence of the rate seems to fit the theory better than was the case with Ramsperger's data. In §8 the effect of helium is discussed. It activates azomethane, being 0.120 as effective as azomethane itself. In §9 the possibility of the azomethane decomposition being a chain reaction is considered. It is concluded that if it is a chain reaction the chain is very short and its length is independent of temperature and pressure over the range studied in this research.
The Relative Atomic Weight of Oxygen in Water and in Air A Discussion of the Atmospheric Distribution of the Oxygen Isotopes and of the Chemical Standard of Atomic Weights
Authors: Dole Malcolm
Published: January 2005

A difference in the density of water made from atmospheric oxygen plus tank hydrogen and aqueous oxygen plus tank hydrogen is interpreted as indicating that the atomic weight of oxygen in the air is 0.000108 atomic weight units heavier than the oxygen of Lake Michigan water. This observation finds experimental confirmation in the work of several other investigators and can be applied in certain cases to the reinterpretation of already existing data, clarifying several anomalous and inexplicable effects. The difference in atomic weights can be accounted for quantitatively by assuming that an isotopic exchange equilibrium of the type discussed by Urey and Greiff occurs at a temperature of —50°C in the lower regions of the stratosphere. The distribution of oxygen isotopes in the atmosphere is calculated by means of the usual hypsometric equation, but the separation due to gravity is not sufficient to explain quantitatively the excess atomic weight of atmospheric oxygen. The chemical and physical standards of atomic weights are discussed and the proposal is made that a single standard based on the mass of a pure isotope such as protium be adopted.
Viscosity, Plasticity, and Diffusion as Examples of Absolute Reaction Rates
Authors: Eyring Henry
Published: January 2005

Since to form a hole the size of a molecule in a liquid requires almost the same increase in free energy as to vaporize a molecule, the concentration of vapor above the liquid is a measure of such ``molecular'' holes in the liquid. This provides an explanation of the law of rectilinear diameters of Cailletet and Mathias. The theory of reaction rates yields an equation for absolute viscosity applicable to cases involving activation energies where the usual theory of energy transfer does not apply. This equation reduces to a number of the successful empirical equations under the appropriate limiting conditions. The increase of viscosity with shearing stress is explained. The same theory yields an equation for the diffusion coefficient which when combined with the viscosity and applied to the results of Orr and Butler for the diffusion of heavy into light water gives a satisfactory and suggestive interpretation. The usual theories for diffusion coefficients and absolute electrical conductance should be replaced by those developed here when ion and solvent molecule are of about the same size.
Wave-Mechanical Treatment of the LiH Molecule
Authors: Knipp Julian K.
Published: January 2005

Variational treatments of the LiH molecule and LiH+ ion have been carried out in which the two electrons of the inner shell of the Li atom are represented by Slater wave functions and the orbitals of the two valence electrons are treated after the method of James and Coolidge (but without the interelectronic distance as one of the coordinates). In this treatment elliptical coordinates are used for the expression of the wave function for the outer electrons, which takes the form of an exponential times a power series. The energy matrix for the LiH molecule contain the matrix terms for the LiH+ ion, for which calculations were also made. The lowest state of the LiH+ ion is a 2Σ state with the dissociation products normal hydrogen and ionized lithium and is the only one-quantum state. The use of a very flexible eleven-term function gives at an internuclear distance of three Bohr radii an energy of repulsion of 0.181 ev. The slope of the potential energy curve at this point is found to be —0.791 ev per Bohr radius. The lowest state of the ion is surely stable with an equilibrium distance somewhat greater than three Bohr radii. The energies of the four two-quantum 2Σ states of LiH+ at the same internuclear distance are obtained from the next four roots of the eleventh-order determinantal equation used to obtain the energy of the lowest state. These states are found to be quite strongly repulsive at this distance. On applying the variational method to the ground state of the neutral LiH molecule, it is found that the best value for the calculated binding energy that can be expected is smaller than the observed value by over a half volt. The addition of two terms containing the cosine of the difference of the azimuthal angles of the two outer electrons improves the calculated energy by 0.13 ev. An eight-term wave function has been tried for the 3Σ state of LiH dissociating to the same products as the ground state. The energy found is a repulsion of 1.89 ev at a distance of three Bohr radii, the equilibrium distance of the ground state.
The Vibration-Rotation Energy Levels of Polyatomic Molecules II. Perturbations Due to Nearby Vibrational States
Authors: Wilson E. Bright
Published: January 2005

The use of the Wang secular equation for the interpretation of the rotational structure of a vibration-rotation band of an asymmetrical top molecule is not justified if either of the vibrational states involved in producing the band is perturbed by another vibrational state of nearly the same energy. The present paper discusses the conditions under which such a perturbation is to be expected and gives the secular equation which should be used instead of the Wang determinant in case the perturbation is important. This equation assumes a somewhat simpler form when applied to orthorhombic molecules, in which case it involves only one parameter in addition to the three moments of inertia.
The Crystal Structure of Silver Phosphate
Authors: Helmholz Lindsay
Published: January 2005

A new value for the oxygen parameter in the structure of silver phosphate has been determined which gives the P–O separation in the phosphate group as 1.61A±0.03A. The value found here is slightly larger than that determined from an analysis of the crystal KH2PO4. The slight increase in P–O distance is explained on the basis of the nature of the phosphate group and of some covalent bond formation between oxygen and the surrounding silver atoms. To get qualitative agreement between calculated and observed intensities it was found necessary to treat the silver atoms as oscillators with tetragonal symmetry, the symmetry of their environments in the crystal. The ratio of the amplitudes of vibration along the tetragonal axis and perpendicular to it has been evaluated from the data. This result is discussed in relation to the structure of silver iodide.
Viscosity and Diffusion Coefficients of Atomic Hydrogen and Atomic Deuterium
Authors: Amdur I.
Published: January 2005

The viscosity of atomic hydrogen has been recalculated from Harteck's experimental values for the relative viscosity of atomic-molecular hydrogen mixtures, on the assumption that atomic hydrogen like molecular hydrogen may be regarded as a van der Waals gas. The numerical results confirm this assumption and permit the evaluation of diffusion coefficients for H–H2, D–D2, H–D2, D–H2 and D–H binary mixtures as well as the viscosity of atomic deuterium.
Quantum-Mechanical Treatment of Helium Hydride Molecule-Ion HeH+
Authors: Beach J. Y.
Published: January 2005

Helium hydride molecule-ion has been treated by the variation method, including ionic and polarization terms in the variation function and varying the effective nuclear charge. The equilibrium internuclear distance is found to be 1.57a0. Fitting a parabola to the lower part of the best potential energy curve leads to a value of 0.43 megadyne/cm for the force constant and a value of 2800 cm—1 for the fundamental vibration frequency. The minimum energy obtained for the system is —5.844WH, which, when subtracted from the best value for the energy of the helium atom using the same type of variation function, gives a value for the dissociation energy of 2.02 ev. The doubly charged ion, HeH++, is found to be unstable.