bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Heat Conduction in Thermal Gaseous Explosions
Authors: Rice O. K.
Published: January 2005

The theory recently developed by Frank-Kamenetzky for thermal explosions in which heat is removed by conduction only, has been applied to the azomethane, ethyl azide and methyl nitrate explosions. A fairly detailed discussion has been given of the experimental results and their relation to the theory. In the case of azomethane and ethyl azide the conclusion is reached that at low pressures thermal conduction as contrasted to convection is an important, if not the exclusive, method of removal of heat from the reacting gas, with deviation appearing at high pressures. As was already concluded by Rice and Campbell, the results appear to indicate that the methyl nitrate explosion is not a thermal explosion. Certain criticisms directed by Frank-Kamenetzky against the determination of the heat of reaction from the induction period, as carried out by Rice and Campbell, have been considered and refuted.
The Reaction of Hydrogen Atoms with Butane
Authors: Steacie E. W. R. , Brown E. A.
Published: January 2005

The reaction of hydrogen atoms, produced by the Wood-Bonhoeffer method, with butane has been investigated over the temperature range 35° to 250°C. The activation energy is 9±1.5 kcal. The products consist solely of methane at low temperatures. At high temperatures ethane is also formed. It is concluded that the results indicate a mechanism in which a series of ``atomic cracking'' reactions play the main role. The main steps in the postulated mechanism are: Primary processH+C4H10→C4H9+H2.Secondary processes at low temperatures H+C4H9→C3H7+CH3→2C2H5H+C3H7→C2H5+CH3H+C2H5→2CH3H+CH3→CH4.Additional secondary processes at higher temperatures C4H9→C2H4+C2H5H+C2H4→C2H5C3H7→C2H4+CH3H2+C2H5→C2H6+HH2+CH3→CH4+H.
The Thermal Reaction Between Hydrogen and Oxygen II. The Third Explosion Limit
Authors: Oldenberg O. , Sommers H. S.
Published: January 2005

The thermal high pressure explosion of the hydrogen-oxygen mixture (``third explosion limit''), occurring near atmospheric pressure at 560°C, was studied. In the p—T diagram, a section of the limiting curve was determined. The effect of a KCl coat on a Pyrex surface was observed. The investigation of the third explosion limit does not lend itself to a decision between the competing theories of the thermal hydrogen-oxygen reaction.
The Sorting of Mixed Solvents by Ions
Authors: Scatchard George
Published: January 2005

The electrostatic interaction of ions with nonelectrolytes is computed for ethanol-water mixtures over the whole composition range by the Debye treatment which takes into consideration the heterogeneity of the solvent. A simple approximate relation is derived which may be extended to other solvents. The agreement with the experimental measurements is shown to be unsatisfactory. The possibility that the lack of agreement may be due to neglect of the discrete structure of the solvent is discussed qualitatively.
The Effect of the Rotation of Groups about Bonds on Optical Rotatory Power
Authors: Kauzmann Walter , Eyring Henry
Published: January 2005

It is shown that the numerical value of the optical activity of an optically active compound is markedly reduced if the groups surrounding the asymmetric atoms in the compound possess a threefold axial symmetry about the bonds connecting them with the asymmetric atoms. This threefold symmetry may be either inherent in the groups themselves, or it may be acquired by them through the free rotation of the groups about these bonds or by their orienting themselves to equal extents in each of the three possible equilibrium positions about each bond. The order of magnitude of the numerical value of the optical activity is thus a measure of the freedom of orientation about single bonds of the groups in an asymmetric molecule. That this effect is actually a dominant factor in determining the order of magnitude of the optical activity is proved by the contrast in the optical activities of cyclic and open chain compounds. It is shown to have an important effect on the temperature coefficient of optical activity and to lie at the root of the observed differences in the orders of magnitude of the rotatory powers of liquids and crystalline solids. The structures of certain sulphur compounds, polypeptides, and proteins are discussed in the light of the magnitudes of their optical activities.
Potential Energy Functions for Diatomic Molecules
Authors: Hulburt Hugh M. , Hirschfelder Joseph O.
Published: January 2005

The usual Morse functions are determined from the energy of dissociation, the equilibrium separation of the nuclei, and the fundamental vibration frequency. Two additional spectroscopic constants, ωexe and αe, are available for most of the common diatomic molecules and permit us to add a two-parameter correction term to the Morse curve. Both the potential V/D=(1−e−x)2+cx3(1+bx)e−2x and the extended Morse curve of the Coolidge, James and Vernon type, V/D=C2(1−e−x)2+C3(1−e−x)3+C4(1−e−x)4 agree with accurate potentials in those cases where they are known. Here x = 2β(r—re)/re. The constants for the first of these potentials are easy to evaluate and are given for 25 common diatomic molecules. With only a few exceptions, the improved potentials lie above the Morse curves and the corrections for moderately large internuclear separations may amount to ten percent of the energy of dissociation. Our treatment is based on the work of Dunham and the analysis of Coolidge, James and Vernon.
Some Mathematical Methods for the Study of Molecular Vibrations
Authors: Wilson E. Bright
Published: January 2005

Developments which reduce the labor of calculating the vibration frequencies of complex molecules are described. In particular a vectorial scheme is given for obtaining the reciprocal of the matrix of the kinetic energy in terms of valence-type coordinates. A general rule for writing down the coefficients of the transformation to symmetry coordinates is derived together with a method of obtaining the kinetic energy reciprocal matrix (G) in terms of symmetry coordinates with a minimum of algebra. A treatment of redundant coordinates is developed. In addition, reduction of the secular equation by the splitting out of high frequencies, a new type of isotope product rule, and the determination of normal coordinates are discussed. The molecule CH3Cl is worked out as an illustration.
Optical Sensitizing of Silver Halides by Dyes III. The Relation of Sensitizing to the Absorption Spectra and Constitution of Dyes
Authors: Sheppard S. E. , Lambert R. H. , Walker R. D.
Published: January 2005

Optical sensitizing is related to dye structure in general, not confined to particular classes of dyes. While sufficiently strong adsorption to silver halide, and relative insolubility of the adsorbed dye are essential, they are not sufficient conditions. The absorption spectra of adsorbed dyes correspond to their spectra in solution, and are affected in the same way by structural changes, but are not identical therewith. The displacement of the spectrum should be referred to the absorption of the dye in the gaseous state at low pressures; examples are given. This displacement corresponds to an adsorption energy available for sensitizing, but this energy difference may not be available, and is not generally sufficient. For ``molecular'' sensitizing, planarity of the dye molecule appears to be essential, and the following conditions are deduced as necessary and probably sufficient for sensitizing: (i) Planar configuration of dye molecules, respectively of adsorbed dye ions, (ii) edge-on adsorption of planar molecules oriented possibly orthogonally but more probably at an angle of 70° to a (111) plane of the crystal, and (iii) electronic transition in dye ion or dipole on absorption of a photon polarized in an azimuth defined by (i) and (ii). On these bases a hypothesis of coplanar coupling of electronic displacements in the dye and in a congruent plane of the silver halide lattice is advanced. It is suggested that this is a key factor in optical sensitizing by dyes, both for molecular and aggregate sensitizing. Certain other relations of constitution to sensitizing are discussed, including the influence of nuclear (perichrome) changes and of substitution.
The Spreading of Oils on Water Part II. Non-Ionized Molecules Having Only One Polar Group
Authors: Zisman W. A.
Published: January 2005

Experiments are described on the spreading upon water of drops of oil containing small amounts of alcohols, esters, ketones, phenols, non-ionized acids, and non-ionized amines. It is shown that such polar molecules do not cause spreading unless the molal concentration exceeds a certain value, c0, which varies with the nature of the polar group, the chain length, the possible geometrical configurations of the molecule, and with the solubility in oil. The cause of their spreading is demonstrated to be a reversible adsorption at the oil-water interface associated with the osmotic pressure of the polar molecules dissolved in the oil. The average lifetime of adsorption of such molecules is shown to be only a small fraction of that of ionized molecules. A0, the interfacial area per adsorbed molecule at the film pressure of 11.3 dynes per cm, is given for a considerable number of saturated and unsaturated straight- and branched-chain acids and alcohols. The observed changes of A0 with chain length and polar group are explained on the basis of structural and kinetic considerations. Certain new spreading phenomena due to the formation of colloidal suspensions and crystalline precipitates of the polar compounds are described, and use is made of the latter to measure the solubility in oils of the various straight chain saturated acids and alcohols.
Thermodynamic Properties of Binary Solid Solutions on the Basis of the Nearest Neighbor Approximation
Authors: Lassettre Edwin N. , Howe John P.
Published: January 2005

An approximate method of computing the partition function of a binary solid solution is formulated. If the only constraints are on the mean energy and mean composition, it is shown that no metastable phase is predicted. The partition function is shown to be obtainable from the largest eigenvalue of a quadratic form and the condition for a phase transition is shown to be related to the degeneracy of the largest eigenvalue. The physical interpretation of the eigenfunction is shown to be related to the probability of surface configuration, while the square of the eigenfunction is related to the probability of a configuration on the interior of the crystal. Some simple examples are discussed which are related to the effect of coordination number on phase transitions.
The Pyrolysis of Formaldoxime
Authors: Taylor H. Austin , Bender H.
Published: January 2005

Formaldoxime decomposes in a first-order reaction to give hydrogen cyanide and water at a rate k = 109.5e—39000/RT sec—1. The products react together at a slower rate to give principally carbon monoxide and ammonia although nitrogen, hydrogen, ethane and traces of unsaturate are also produced. The reaction is probably heterogeneous on a clean glass surface. It is accelerated by traces of air and by nitric oxide. These facts offer an adequate explanation of the fate of methyl radicals in nitric oxide inhibited reactions by the isomerization of the CH3NO complex into formaldoxime.
Infra-Red and Raman Spectra of Polyatomic Molecules XV. Diborane
Authors: Stitt Fred
Published: January 2005

The infra-red spectrum of diborane has been studied on a prism spectrometer from 400 to 4000 cm—1. Absorption occurs over much of the region investigated. A reliable and complete analysis of the infra-red and Raman spectra of diborane must await further work, but two alternative tentative analyses of the main features are presented which are in accord with the heat capacity of gaseous diborane from 100 to 300°K. One of these analyses is based on the assumed existence of a singlet electronic state at 412 cm—1 above the ground state and requires the potential barrier to internal rotation within the molecule to be of the order of 15,000 calories per mole. The alternative analysis assumes that no electronic state lies less than 1600 cm—1 above the ground state and requires a potential barrier of about 5000 calories per mole. Both analyses assume an ethane-like structure for the diborane molecule.
The Spreading of Oils on Water Part III. Spreading Pressures and the Gibbs Adsorption Relation
Authors: Zisman W. A.
Published: January 2005

The Gibbs adsorption relation between surface tension and concentration is applied to new data on the equilibrium pressure of spreading of oil drops containing long-chain alcohols. It is found that the graph of pressure against concentration is an hyperbola and an empirical formula is fitted to the measurements for each alcohol. There is derived an equation of state of the polar molecules adsorbed at the oil-water interface. It is then shown that the interfacial monolayer is a stable mixed film made up of polar and non-polar molecules, the latter being components originally of the oil. It is pointed out that these conclusions may be significant in the interpretation of film phenomena such as are involved in the stabilization of emulsions and the structure of cell membranes.
The Effect of Electrostatic Forces on Electrokinetic Potentials
Authors: Eversole W. G. , Boardman W. W.
Published: January 2005

Assuming that the ions in solution near a charged wall are subjected only to electrostatic and kinetic forces, it is shown that the potential gradient normal to the wall is determined principally by the valence and concentration of the ion of opposite charge to the wall. Assuming that the valence and concentration of this ion determine the effect of the salt on the electrokinetic potential of the wall, the surface potential of the wall and the thickness of the immobilized liquid layer are calculated from electrokinetic potential data. Salts of ``normal'' ions (NaCl, BaCl2, etc.) cause relatively small changes in the surface potential and thickness of the immobilized layer at a glass surface and these changes occur only at very low salt concentrations. Salts containing ``abnormal'' ions (H+, OH—, La+++, etc.) produce larger changes and the change continues over a much wider concentration range. The extreme effectiveness of salts like AlCl3 and ThCl4 in lowering negative electrokinetic potentials cannot be accounted for by the higher valence of the ions.
The Partition Functions of Molecules with Internal Torsion I. Single Asymmetric Top Attached to Rigid Framework
Authors: Price Donna
Published: January 2005

Crawford's method of treating ``pseudo-rigid'' molecules is extended to the case involving an asymmetric top. The exact classical kinetic energy for a molecule consisting of a rigid framework to which asymmetric tops are attached is given. From this the quantum-mechanical operator is derived for the case of one top of small moment of inertia and of small asymmetry. The energy matrix for the molecule is obtained from the operator; and by use of a perturbation method, the partition function for translation, over-all rotation and internal rotation, correct to the second order, is obtained from the matrix. This includes effects due to translational and angular momentum couplings.
The Mercury Photosensitized Reactions of Ethylene
Authors: LeRoy D. J. , Steacie E. W. R.
Published: January 2005

An investigation has been made of the mercury (3P1) photosensitized reactions of ethylene. In addition to hydrogen and acetylene the main products are butene, butane and hexenes. The variation of the rate with the pressure of ethylene suggests that a deactivation process is involved, the initial process being of the type C2H4+Hg(3P1)→C2H4*+Hg(1S0)followed by C2H4*+C2H4→2C2H4.or C2H4*→C2H2+H2.Polymerization arises largely by a free radical mechanism and butane is formed by the reactionsH2+Hg(3P1)→2H+Hg(1S0)H+C2H4→C2H52C2H5→C4H10.The mechanism is shown to be consistent with the value found for the quantum yield.
The Near Infra-Red Spectra of Linear Y2X2 Molecules Part I. Theory
Authors: Shaffer Wave H. , Nielsen Alvin H.
Published: January 2005

Complete expressions for the rotation-vibration energies of the linear Y2X2 molecules, through second order of approximation, have been obtained in the form E = hc(GV+FR). The vibrational term GV obtained agrees exactly with that found by Wu and Kiang, but there are numerous points of difference in the rotational term FR.
The Crystalline Structure of Pt3O4
Authors: Galloni Ernesto E. , Roffo Angel E.
Published: January 2005

By x-ray diffraction, the chemical formula and crystal structure of Pt3O4 have been established. The crystal lattice has a body-centered cube symmetry. The edges of the cubes are 6.226A long, and there are two molecules per unit cell. A chemical method for preparing this oxide has been given by Jörgensen but Wöhler claims that the compound thus obtained is a mixture of monoxide and dioxide rather than a separate chemical entity, see references 2 and 3.
Theory of Some van der Waals Molecules
Authors: Heller Ralph
Published: January 2005

Using a potential function of the form V(R)=A(ρ)e−R/ρ−c1R6−c2R8−c3R10−c4R12,the vibrational wave number and energy of dissociation of the molecules HgHe, HgNe, HgA, HgKr, HgXe, Hg2, (O2)2 and (NO)2 in the normal state are calculated. It is found that, if the single value ρ=0.28A is chosen, satisfactory agreement is obtained with experimental data except in the case of (NO)2. The latter structure is believed to owe its binding partly to first-order attractive forces.
Second-Neighbor Interactions and the Critical Behavior of Binary Solid Solutions
Authors: Chang T. S.
Published: January 2005

The Thiele semi-invariants γ1, γ2 and γ3 of a binary solid solution are calculated with the assumption that there are second-neighbor interactions as well as first-neighbor interactions. The results give a decrease of the critical temperature Tc at which the superlattice sets in, an increase of the local order σ at Tc, an increase of the discontinuity of the specific heat, thus in general agreement with the results obtained by applying Bethe's method to the same problem.
Remarks on the Fluorescence, Phosphorescence and Photochemistry of Dyestuffs
Authors: Franck James , Livingston Robert
Published: January 2005

Many of the apparently conflicting facts of the photochemistry as well as of the phosphorescence and of the fluorescence quenching of dyes can be given a rational and unified interpretation if it be assumed that an electronically excited dye molecule can go over, by a process of internal conversion, to the electronic ground state of a reactive energy-rich tautomer. The endothermic reversion of such a tautomer to the electronically excited state of the original molecule would explain the weak, temperature dependent phosphorescence observed in some systems. In the presence of a suitable reducing agent the reactive tautomer may be reduced to a semiquinone. This process and the likely subsequent reactions are sufficient to explain the majority of dye-sensitized photo-oxidations as well as the photo-bleaching of dyes by reducing agents. In the case of chlorophyll, and possibly a few other dyes, it appears to be necessary to assume that the tautomer and a normal dye molecule can undergo a process of disproportionation. The assumption of this step leads directly and simply to an explanation of the rapid reversible bleaching of chlorophyll which is consistent with the other known photochemical and optical properties of this substance. In addition to the more familiar reaction steps which have been assumed as follow reactions in setting up the various mechanisms, it is necessary to include a step in which the HO2 radical reduces a partially oxidized dye molecule (i.e., radical) back to the normal state. The several reaction steps assumed in these various schemes appear to be energetically feasible.
The Long Wave-Length Spectra of Aldehydes and Ketones Part I. Saturated Aldehydes and Ketones
Authors: McMurry Henry L.
Published: January 2005

Intensity calculations are used to help in deciding which of two theoretically predicted transitions should be identified with the weak longest wave-length absorption characteristic of the unconjugated ––C = O group. In terms of the localized LCAO MO and the AO approximations used, one of these transitions is forbidden while the calculated intensity for the other, allowed, transition is much too large to be compatible with the low intensities observed for the absorption. The observed absorption should, therefore, be ascribed to the forbidden transition. The Q and S integrals needed for the calculations, involving AO's of the C and O atoms, are tabulated. The intensity for the allowed transition, when expressed using semilocalized LCAO MO's depends somewhat on the nature of the atoms attached to the C=O group. The absorption regions appearing at shorter wave-lengths in ketones and aldehydes are discussed. It is concluded that the λ1900 region in ketones is characteristic of the C=O group and probably is due either to a Rydberg transition or most likely to the allowed transition for which intensity calculations have been made. If the latter is true the upper level of the λ1900 absorption could be largely responsible for the perturbations which cause the appearance of the long wave-length forbidden transition. It is shown that the long wave-length absorptions from the ––C = S group can be explained in the same manner as those for the ––C=O group.
The Long Wave-Length Spectra of Aldehydes and Ketones Part II. Conjugated Aldehydes and Ketones
Authors: McMurry Henry L.
Published: January 2005

An interpretation of the long wave-length absorption regions of conjugated aldehydes and ketones is given. The strong regions can be assigned to transitions of the N→V1 type known to produce the intense long wave-length absorption in polyenes. The weak absorption regions, which are characteristic of the carbonyl group, can be explained as arising from the type of transition previously proposed to explain the weak carbonyl absorption in saturated aldehydes and ketones. This transition involves the excitation of a loosely bound electron occupying a nonbonding orbital lying in the molecular plane and across the C–O direction, to an excited molecular orbital with a node in this plane. In conjugated molecules several of these excited MO's exist and transitions to them all are predicted. The longest wave-length carbonyl absorption represents a transition to the lowest of these MO's and the observed shift of this absorption toward longer wave-lengths with each addition to the number of conjugated bonds in the chain can be explained by the fact that this lowest excited MO is reduced in energy as the length of the chain increases. The longest wave-length absorption for quinones and for aromatic aldehydes and ketones can be explained by the same process as that producing this absorption in chain molecules. The long wave-length spectra of molecules containing conjugated C=S groups are shown to be similar to those for the analogous molecules containing C=O groups. The absorption from the C=S group is observed at longer wave-lengths because the orbital from which excitation comes is less firmly bound than in C=O.
Dielectric Constants of Aliphatic Ketones
Authors: Cole Robert H.
Published: January 2005

The dielectric constants and densities of eight aliphatic ketones were determined over nearly the entire temperature range of the liquid phase. The results lead to the conclusion that dipole-dipole coupling is the important factor in determining the dielectric constants of these liquids. The data show definite departures from Onsager's theory. Use of the Onsager formula to calculate dipole moments from dielectric constant data on the pure polar liquids, as suggested by Böttcher, is not justified in the case of the ketones and is to be undertaken with caution in other cases. It is not possible to attribute the departures for the ketones to proton bonding. The results are, however, consistent with Kirkwood's more detailed theory. It is further shown that dielectric constants of normal aliphatic alcohols are consistent with Kirkwood's theory as applied to a crude model of the liquid ``structure'' of these alcohols.
Adsorption and Nitrogen Isotope Exchange on Metallic Osmium Catalysts
Authors: Guyer Walter R. F. , Joris G. G. , Taylor Hugh S.
Published: January 2005

Osmium catalysts prepared by decomposition-reduction of ammonium osmium chloride with hydrogen at 573°K show activated adsorption of hydrogen from 80 to 537°K. At the lowest temperature the adsorption is in part van der Waals adsorption. Van der Waals adsorption of nitrogen on the same catalyst decreases continuously from 80°K. The nitrogen isobar at 1 atmos. pressure shows a minimum at 350°K and then shows increasing adsorption to a maximum at 428°K. The increase is attributed to activated adsorption of nitrogen which velocity measurements confirm. From a nitrogen adsorption isotherm at 80°K the area per gram of catalyst is computed to be 30.8 square meters. Only 4 percent of this area is covered at 1 atmos. pressure by nitrogen at 428°K. The nitrogen adsorption is less than 10 percent of the hydrogen adsorption at 1 atmos. pressure in the temperature range of 273–573°K. Such osmium catalysts show progressive sintering when heated at 673°K. The nitrogen isotope exchange reaction N228+N230 = 2N229 on these catalysts is just measurable at 473°K and very rapid at 573°K, with an activation energy of 21.8 kcal. The reaction is not second-order and is measurably inhibited by even 3 percent of hydrogen in the gas. With hydrogen concentrations of 50 percent and upwards there is no measurable exchange at 550°K. Oxygen poisons the exchange reaction which has an activation energy of 26 kcal. on the poisoned catalyst. Ammonia decomposes on the catalyst at 573°K at least 6 times as fast as the exchange reaction occurs, yielding an N2 : 3H2 mixture. The data on exchange point to a mechanism in which the slow process is the migration of atomically bound nitrogen on a surface on which active centers are few. Repeated adsorption and desorption of nitrogen from configurationally more complex active centers is a possible alternative mechanism for the exchange. Experiment cannot yet decide whether the breaking of bonds in the adsorption of the nitrogen molecule is the rate-determining process.
The Cadmium Photosensitized Reactions of Propane
Authors: Steacie E. W. R. , LeRoy D. J. , Potvin R.
Published: January 2005

An investigation has been made of the cadmium (53P1) photosensitized reactions of propane and of propane-hydrogen mixtures at a temperature of 310°C. The main products are hydrogen and hexanes, together with smaller amounts of methane, butane, pentanes and heptanes. The quantum efficiency of propane decomposition is roughly 0.6. The results indicate that the primary reaction is a C–H bond split, Cd(3P1)+C3H8=CdH+C3H7.The main secondary reactions are H+C3H8=C3H7+H22C3H7=C6H14.The liquid products of the reaction appear to be mainly 2,3-di-Me-butane and/or 2-Me-pentane. This indicates that mainly secondary hydrogens are attacked, yielding the isopropyl radical. More C–C bond splitting occurs than is the case in the mercury photosensitized reaction at the same temperature. A possible explanation of this is that reactions are occurring which involve the CdH molecule.
Dispersion and Absorption in Dielectrics I. Alternating Current Characteristics
Authors: Cole Kenneth S. , Cole Robert H.
Published: January 2005

The dispersion and absorption of a considerable number of liquid and dielectrics are represented by the empirical formula ε*−ε∞=(ε0−ε∞)/[1+(iωτ0)1−α]. In this equation, ε* is the complex dielectric constant, ε0 and ε∞ are the ``static'' and ``infinite frequency'' dielectric constants, ω=2π times the frequency, and τ0 is a generalized relaxation time. The parameter α can assume values between 0 and 1, the former value giving the result of Debye for polar dielectrics. The expression (1) requires that the locus of the dielectric constant in the complex plane be a circular arc with end points on the axis of reals and center below this axis.

If a distribution of relaxation times is assumed to account for Eq. (1), it is possible to calculate the necessary distribution function by the method of Fuoss and Kirkwood. It is, however, difficult to understand the physical significance of this formal result.

If a dielectric satisfying Eq. (1) is represented by a three-element electrical circuit, the mechanism responsible for the dispersion is equivalent to a complex impedance with a phase angle which is independent of the frequency. On this basis, the mechanism of interaction has the striking property that energy is conserved or ``stored'' in addition to being dissipated and that the ratio of the average energy stored to the energy dissipated per cycle is independent of the frequency.
The Measurement of the Dielectric Constants of Vapors and the Polarizations of Trimethylaluminum, Dimethylaluminum Chloride and Methylaluminum Dichloride
Authors: Wiswall R. H. , Smyth C. P.
Published: January 2005

Modifications of an apparatus for the measurement of the dielectric constants of vapors are described. The apparatus has been used to determine the dielectric constants of the vapors of trimethylaluminum and dimethylaluminum chloride over a range of temperature and pressure, and methylaluminum dichloride has been measured in solution with another apparatus. The accurate calculation of the dipole moments of the molecules is prevented by strong molecular association. The data indicate a strong probability that the single trimethylaluminum molecule has a pyramidal structure and that the aluminum-carbon bond is predominantly covalent.
The Vapor Density of Iodine at High Temperatures
Authors: Perlman M. L. , Rollefson G. K.
Published: January 2005

By measurement of pressure-volume products of iodine vapor at temperatures between 723°K and 1274°K, it was determined that the vapor in this region consists of diatomic molecules and atoms in equilibrium. No evidence was found for the existence of triatomic molecules. The heat of dissociation of iodine, calculated from the experimentally determined equilibrium constants and the known energy levels of the I atom and the I2 molecule, was found to be 35,514±50 calories. This is in good agreement with the value obtained by Brown from spectroscopic data alone, ΔH00=35,547±20 calories. Other quantities calculated were ΔF0298.1°K = 28,882±50 calories and ΔH0298.1°K = 36,057±50 calories.
Low Velocity Hydrogen Ion Scattering in Hydrogen, Water and Ammonia
Authors: Russell A. S. , Fontana C. M. , Simons J. H.
Published: January 2005

Improved technique has enabled more precise measurements to be made of the effective cross section for scattering of hydrogen, water, and ammonia for low velocity protons and of hydrogen for low velocity H2+ and H3+. From the measurements of proton scattering in hydrogen and ammonia and H3+ scattering in hydrogen, and the use of certain assumptions, the average force laws can be evaluated and the energy of combination estimated in the first two cases. The proton affinities thus calculated for hydrogen and ammonia agree with previous estimates. For H2+ in H2 an evaluation of force law and an estimate of energy of combination cannot be made, but the large interaction is a phenomenon of some interest. Further increase in precision, separation of scattering from neutralization, and extension of measurements to lower velocities of ions is necessary also to evaluate the force law and proton affinity of water. As measurements of this kind can be made using many kinds of ions, each of which can be scattered in a great variety of gases, much information of value can be obtained such as force laws, proton affinity or absolute basicity of substances, energies of solvation of ions, etc.
Raman Spectra of Acetylenes IV. Carbon Isotope Effect in Acetylenes
Authors: Cleveland Forrest F. , Murray M. J.
Published: January 2005

The carbon isotope shift in the frequency near 2200 cm—1 has been calculated for H–C13≡C12–H, CH3–C12≡C13–H, CH3–C13≡C12–H and CH3–C13≡C12–CH3 from the valence force equations, assuming a four-mass, linear oscillator. The results were —27, —26, —50 and —33.5 cm—1, respectively. Weak lines which may correspond to isotope shifts were observed for the monosubstituted acetylenes, 1-heptyne (—21 and —53 cm—1), 4-methoxy-1-butyne (—24 and —53) and phenylethyne (—24 and —54), and for the disubstituted acetylenes, 1-phenyl-1-butyn-3-one (—37), 1-phenyl-1-butynol-3 (—33), 1-phenyl-1-butyne (—29), 3-hexyne (—26), 3-octyne (—36) and 5-decyne (—38 cm—1). Shifts of —27 and —33 cm—1 for acetylene and dimethylacetylene, respectively, have been reported by Glockler and Renfrew.
The Thermodynamic Properties of Phosphorus, Phosphine, and Some Phosphorus Halides
Authors: Stevenson D. P. , Yost Don M.
Published: January 2005

A critical study of the equilibrium and molecular data for phosphorus and some of its compounds has been made and is described. The data are used to calculate the entropies and free energies of the substances considered.
The Thermal Reaction Between Hydrogen and Oxygen III. The Temperature Coefficient of the Steady Thermal Reaction
Authors: Oldenberg O. , Sommers H. S.
Published: January 2005

The thermal combination of hydrogen and oxygen, investigated in various vessels (quartz, clean Pyrex, Pyrex covered with KCl), follows the Arrhenius law over a considerable temperature range in which, according to Hinshelwood, a chain reaction in the gas phase, broken at the wall, must be assumed. It is concluded that in this temperature range the chains are not branched.
An X-Ray Study of Liquid Benzene, Cyclohexane and Their Mixtures
Authors: Bell Paul H. , Davey Wheeler P.
Published: January 2005

X-ray (Mo K alpha) studies were made of pure benzene, pure cyclohexane, and their mixtures, using a Geiger-Mueller counter with balanced filters. The benzene showed at 25°C a rather sharp intense peak at the customary 8°40′ and a new broader peak of about one-eighth intensity at 4°20′. The cyclohexane showed a similar pair of peaks at 8°0′ and 4°0′. The mixtures all showed a broad peak of low intensity reaching from 4°0′ to 4°20′ and three sharp peaks at 8°0′, 8°20′, and 8°40′ superimposed on a broad peak which reached from about 8°0′ to about 8°40′. The positions of the three sharp peaks were not affected by the proportions of the two components, and their relative intensities were independent of amount of stirring. The customary shift with temperature was observed on all peaks. The results are consistent with a cybotatic type of picture. Benzene is pictured as having short-lived highly organized groups of —B–B–B–B— floating in a chaotic sea of disorganized benzene molecules. The peak at 8°40′ is thought to be due to the presence of vibrating groups whose extreme positions simulate groups of —B–B–B–B–B–B— and —B–B–B–B–B–B—. Cyclohexane would contain similar groups of —C–C–C–C—. The mixtures are assumed to contain —B–B–B–B—, —C–C–C–C—, and —B–C–B–C—. The presence of any considerable amount of more complicated groupings is obviously highly improbable.
The Infra-Red Bands of Hydrogen Peroxide at λ9720 and the Structure and Torsional Oscillation of Hydrogen Peroxide
Authors: Zumwalt Lloyd R. , Giguère Paul A.
Published: January 2005

A high dispersion study of the OH bands of hydrogen peroxide in the photographic infra-red is described. The rotational structure of the two hybrid bands at 10,283.68 cm—1 and 10,291.08 cm—1 is analyzed. The small moment of inertia of hydrogen peroxide is found to be 2.786 × 10—40 g cm2 while the harmonic mean of the two larger moments of inertia is found to be approximately 33.9 × 10—40 g cm2. The planar cis-configuration is ruled out spectroscopically and it is concluded that hydrogen peroxide exists in a non-planar form. It is tentatively decided that the vibrational levels of hydrogen peroxide are doubled and that the double minimum potential associated with the internal rotation of the OH groups has a high and a low barrier.
Tables of Thermodynamic Functions of Paramagnetic Substances and Harmonic Oscillators
Authors: Hull J. R. , Hull R. A.
Published: January 2005

Numerical values of the partition function, magnetic moment, entropy, and temperature derivative of the entropy are tabulated for free paramagnetic ions with j = 1/2, 3/2, and 5/2. These tables are needed in connection with experiments on adiabatic demagnetization. As a byproduct, the thermodynamic functions for an Einstein oscillator are computed numerically to a higher degree of accuracy than in the tables available in the literature.
High Rotational Levels and the Partition Function for Hydrogen
Authors: Woolley Harold W.
Published: January 2005

The ordinary formula for the rotational energy of a simple rotating vibrator, when applied to a diatomic molecule, consists of the first few terms of a series that becomes poorly convergent for levels of high rotational energy. Inversion of the series results in a better approximation. An illustration is given using the results of calculations for the normal state of hydrogen. The inverted series is especially suited to derivation of approximation formulas for the partition function. Such an approximation formula should not be carried to powers of T so high that lack of coefficients for the ordinary formula introduces significant error.
On the Polymerization of Ethylene and Propylene by Free Alkyl Radicals
Authors: Beeck Otto , Rust F. F.
Published: January 2005

Methyl- and ethyl-induced polymerizations of ethylene and propylene were carried out in static, as well as flow experiments. The latter allowed collection of enough reaction products for analysis by low temperature distillation. Efficiency of polymerization in propylene is much lower than in ethylene which is explained by the easy formation of allyl radicals. Analyses of the reaction products readily indicate that the polymer is formed by the successive addition of olefin molecules to radicals, that chain transfer through radical decomposition takes place, and that the chains are terminated by disproportionation or association of two radicals.
The Efficiency of the Primary Photochemical Process in Solution
Authors: Atwood Kenton , Rollefson G. K.
Published: January 2005

A study has been made of the effect of an inert solvent on the efficiency of the primary process in the photolysis of oxalyl bromide and nitrosyl chloride. The oxalyl bromide was studied at the wave-lengths 2650, 3130, 3650, 4047, and 4358A, the nitrosyl chloride at 3650, 4047, 4358, 5461, and 5790A. In order to eliminate the back reaction between nitric oxide and chlorine, oxygen was introduced which converted the nitric oxide into nitrogen dioxide. The solvent used was carbon tetrachloride. Quantum yields for nitrosyl chloride showed only a slight trend ranging from 0.7 at 3650A to 0.5 at 5790A as compared to approximately 2 at all wave-lengths in the gas phase. Oxalyl bromide gave approximately the same quantum yield in solution as in the gas phase at 2650A, i.e., ∼0.9, and the values in solution decreased to ∼0.3 at 4358A with most of the change occurring between 3130 and 3650A. The results are discussed in terms of the Franck-Rabinowitch hypothesis and it is pointed out that they are most readily accounted for by assuming a deactivating action of the solvent rather than a high efficiency of recombination. A new quartz capillary arc of high intensity is described. The equilibrium N2O4=2NO2 has been studied in carbon tetrachloride solution and the equilibrium constant at 25°C found to be 6.4×10—5, concentrations expressed in mole fractions.
The Unmixing Effect of Sound Waves on Liquid Mixtures
Authors: Herzfeld Karl F.
Published: January 2005

The equations for sound waves passing through liquid mixtures are given. The amount of unmixing and the increase in sound absorption are calculated and found to be too small for observation.
The Thermal Reaction Between Hydrogen and Oxygen IV. Comparison of the Thermal and the Photochemical Reaction
Authors: Oldenberg O. , Sommers H. S.
Published: January 2005

Some recent observations are compared with theories of the thermal and the photochemical reaction between hydrogen and oxygen. The conclusion is reached that for both cases the gas phase reaction observed at higher temperatures is best described by the Bonhoeffer-Haber chain.
Vibration-Rotation Energies of the Planar XY3 Molecular Model
Authors: Silver Samuel , Shaffer Wave H.
Published: January 2005

The vibration-rotation energies of the planar XY3 molecular model are investigated to the second order of approximation, including the cubic and quartic anharmonic terms of the potential energy, the Coriolis interactions between the degenerate oscillations and the total angular momentum, the dependence of the moments of inertia upon the vibrational state, and the centrifugal expansion terms. The contact transformation developed by Shaffer, Nielsen, and Thomas is applied to the Wilson-Howard Hamiltonian, and it is found that the energies are simply the diagonal elements of the transformed Hamiltonian. The energies are expressed in term value form, E/hc=Gvib+Frot—ζh/4π2cIzz0(l2—l4)K, Gvib, Frot, and ζ being given in terms of the constants appearing in the Hamiltonian. The dependence of the moments of inertia, Ixx and Izz, upon the vibrational states is determined, and it is found that the quantity Δ=Izz—2Ixx is independent of the anharmonic constants, depending only on the dimensions of the molecule, the normal frequencies, and the vibrational state.
Rotation-Vibration Energies of the Pyramidal XY3 Molecular Model
Authors: Shaffer Wave Henry
Published: January 2005

Complete expressions have been derived for the rotation-vibration energies of the pyramidal XY3 molecular model in such a way as to include, through second order of approximation, all contributions to the energies arising from Coriolis interactions, anharmonicities, etc.
The Mechanism of Reactions Involving Excited Electronic States II. Some Reactions of the Alkali Metals with Hydrogen
Authors: Magee John L. , Ri Taikei
Published: January 2005

Some chemiluminescent and quenching reactions of the alkali metals are considered. The reaction which leads to the luminescence of sodium in atomic hydrogen is seen to be adiabatic, and a model potential energy surface, constructed by the semi-empirical method, is found to be in qualitative agreement with the experimental observations. The lowest electronic states of the system Na*H2 are considered in an attempt to understand the mechanism of the non-adiabatic reaction which quenches the sodium D line. It is shown that two crossing points should occur, one of them involving a polar state. The rate of the quenching reaction is discussed in terms of the absolute reaction rate theory.
The Inductive Mechanism of Dipole Interaction and the Estimation of Molecular Dipole Moments
Authors: Remick A. Edward
Published: January 2005

The problem of calculating molecular dipole moments from constant bond moments is impractical since bond moments are greatly altered by their environment. As an alternative method it is proposed that molecules be considered as substitution products of a simple system of reference compounds whose bond moments are altered by the substitution. Equations for calculating these dipole interactions are developed on the assumption that only the inductive mechanism of electron displacement is operative in saturated molecules. The values of the dipole moments of polyhalogeno-paraffins calculated by means of these equations are found to be in rough accord with the facts. The agreement is much improved by empirical alterations of the values for the electronic polarizations of certain electron groups.
The Raman Spectra of Mono- and Dichlorobenzenes
Authors: Sponer H. , Kirby-Smith J. S.
Published: January 2005

Raman spectra were taken of gaseous mono- and dichlorobenzenes. Polarization measurements were made for the dichlorobenzenes in the liquid phase. Interpretations of the stronger lines are given in terms of modes of vibration. The experimental results and assignments of the frequencies are collected in Tables I—IV.
Magnetic and X-Ray Studies on Ti and Zr with Dissolved Hydrogen
Authors: Fitzwilliam J. , Kaufmann A. , Squire C.
Published: January 2005

Dissolved hydrogen in Ti and Zr has the effect of changing the lattice of these metals from hexagonal close-packed to a nearly cubic face-centered lattice. The paramagnetic susceptibility of the system Ti–H and also Zr–H has a value at room temperature different from that of the respective pure metals. The dependence of susceptibility on the hydrogen concentration has been investigated for Zr in this article. A small trace of iron impurity which was dissolved in the Zr was found to precipitate out and regain its ferromagnetic property when the Zr was allowed to soak up hydrogen.
Velocity of Sound in Liquids and Chemical Constitution
Authors: Rao M. Rama
Published: January 2005

A study of the recently obtained data on the velocity of sound and density in liquids reveals a simple relation between these quantities namely the law, v⅓M/ρ = R where v is the velocity of sound in the liquid, M the molecular weight, ρ the density and R a constant independent of temperature. It is shown that the velocity of sound cannot be a proper basis of comparison in any homologous series. The result of plotting the constant R against the molecular weight of members of homologous series leads to the equation R = αM + β where α is a general constant and β a characteristic constant for any one homologous series. The difference in R for successive members of homologous series is a constant independent of the series and R is an additive function of the chemical structure. Values of R for hydrogen, carbon, oxygen, bromine, and chlorine are tabulated.
The Heat Capacities of Molecular Lattices I. Introduction
Authors: Lord R. C.
Published: January 2005

The interpretation of the heat capacities of molecular crystals is discussed. The assumption is made that the lattice part of the molecular heat capacity can be represented by a single Debye function with the appropriate number of degrees of freedom. The reasons for supposing that this assumption is valid are considered, and it is shown that one can reasonably expect its validity except at temperatures low in comparison with the characteristic temperature θ of the Debye function. It is proposed to apply this point of view to the interpretation of the heat capacity curves of a number of molecules. The conversion of Cv to Cp is discussed for molecular lattices.
The Heat Capacities of Molecular Lattices II. The Structure of Metallic Lithium
Authors: Lord R. C.
Published: January 2005

The failure of the Debye equation for atomic lattices to hold for the heat capacity of metallic lithium is attributed to the association of lithium atoms in the crystal into diatomic ions. It is then shown, with the help of a reasonable assumption as to the value of the diatomic vibration frequency, that the heat capacity of lithium can be understood without postulating a breakdown of the Debye theory. Some implications of this point of view for the theory of the metallic properties of lithium are pointed out and further experimental work to decide the question proposed.