bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the Bonding of Iron-Group Ions in Fluoride Crystals. I
Authors: Hall T. P. P. , Hayes W. , Stevenson R. W. H. , Wilkens J.
Published: January 2005

This paper describes an investigation by ESR methods of the bonding of iron-group impurity ions with the configurations d3, d5, and d8 in LiF, NaF, KF, KMgF3, and KCdF3. The results indicate that π and σ bonding are comparable in magnitude and provide evidence for the relaxation of ligands on to impurity ions in the alkali halides.
Spectroscopic Absorption of NO in Crystalline and Liquid Krypton
Authors: Pollack Gerald L. , Broida H. P.
Published: January 2005

Transparent mixtures of krypton gas with less than 1% NO were liquefied and then solidified. Absorption spectra between 2000 and 5000 Å were obtained with liquid and crystalline paths of 5 mm at temperatures near the krypton triple point (116°K). Even at the smallest concentrations of NO (less than 0.02%) no trace of discrete spectra of the NOγ system was found. However, a cutoff at short wavelength was observed in the liquid, increasing from 2224 to 2550 Å with increasing concentrations of NO from 0.0177% to 0.646%. This absorption cutoff may be due to the transition from the ground state X 2Π to the theoretically predicted 4Π state. The absorption cutoff in the crystalline material was found only with relatively large amounts of NO and it disappeared in a few minutes, indicating rather rapid diffusion of the NO in the solid.
Electron Spin Resonance Study of Partially Reduced Vanadium Pentoxide
Authors: Ragle J. L.
Published: January 2005

Single crystals of partially reduced vanadium pentoxide have been prepared in the form CuxV2O5 with 0≤x≤0.040, and two distinct types of paramagnetic species have been observed by ESR techniques. Neither of these species is associated with copper (II). For 0≤x≤0.0058, the dominant species is one in which the electron is localized, the hyperfine structure indicating interaction with two equivalent vanadium nuclei. This center is apparently identical to that observable in ordinary laboratory reagent grades of vanadium pentoxide. In addition, for 0.0078≤x, the spectra show a superimposed single narrow line of total width 10–20 G. The g tensor of this species shows that it is still primarily associated with the vanadium sites, but the lack of hyperfine structure indicates a considerable mobility. The latter species is not observed in ``pure'' vanadium pentoxide but is very similar to the mobile species observed in vanadium bronzes.
Anomalous Flow of Zinc Vapor through Pyrex Tubing
Authors: Sears G. W. , Hudson J. B.
Published: January 2005

Observations are reported on the flow of hot zinc vapor through a cold Pyrex tube. A near-zero thermal accommodation coefficient for zinc vapor at the tube wall is deduced. These results are in accord with previous measurements of the nucleation of crystalline zinc on Pyrex glass.
Mass Spectrometric Analyses of the Ions Resulting from the Nuclear Decay of CH3I130 and C2H5I131. Study of Xenon—Hydrocarbon Ions. II
Authors: Carlson Thomas A. , White R. Milford
Published: January 2005

Ions resulting from the nuclear decay of CH3I130 and C2H5I131 have been measured with a specially designed mass spectrometer. From these two studies the percent abundances for the parent ions, [CH3Xe130]+ and [C2H5Xe131]+, are found to be, respectively, 34% and 1.4%. Besides CH3+ and C2H5+, formed directly from the severance of the C–Xe bond of the parent ions, a large variety of fragment ions are also observed. The results are compared with those for a similar study by us on CH3I131, (previously published in this Journal). From these comparisons the following conclusions are reached: (1) the ethyl—xenon ion undergoes decomposition much more readily than the methyl—xenon ion, and (2) the greater recoil energy that is present in the decay of I130 leads primarily to the severance of the organic—xenon bond, with the formation of CH3+. Besides recoil energy, there are also two other sources of excitation: (1) Coulombic shaking, as the result of the sudden change in nuclear charge following beta decay, is used to explain the appearance of the lower-charged Xe ions and most of the fragment hydrocarbon ions. (2) Multiple Auger processes following internal conversion are given as the cause for the more highly charged Xe ions, and their abundance is correlated with the amount of internal conversion present in I130 and I131.
Emendations to Nucleation Theory and the Homogeneous Nucleation of Water from the Vapor
Authors: Oriani R. A. , Sundquist B. E.
Published: January 2005

Recent developments in nucleation theory have vitiated the agreement that was thought to exist between experiments and theory on the condensation of water vapor. The various developments are critically reviewed. The thermodynamic terms in nucleation theory are derived in a more comprehensive manner than heretofore. Arguments are presented to show that the alleged positional entropy contribution to the surface-free energy does not exist. The final expression for homogeneous nucleation rate, without, however, any correction for the effect of surface curvature on surface-free energy, is evaluated. The Kirkwood—Buff equation for the effect of curvature is shown to lead to an impossible situation. A bond-breaking model is developed and used to estimate an upper limit for the correction of the surface-free energy for curvature. It is found that the experimental results for the condensation of water vapor are largely bracketed by the nucleation theory with and without the correction for curvature. It is concluded that the amended classical theory of nucleation is reasonably well verified by experiments on condensation of water vapor.
Paramagnetic Resonance Spectrum of Irradiated Glycylglycine HCl
Authors: Box Harold C. , Freund Harold G. , Lilga K. T.
Published: January 2005

Electron spin resonance measurements on irradiated single crystals of glycylglycine hydrochloride show that the free radical ClNH3–CH2–CONH–CH–COOH is formed. The protons attached to the alpha carbon atom and to the amide nitrogen atom contribute to the hyperfine structure. The ESR spectrum correlates well with the structure of the undamaged crystal.
Raman and Infrared Spectra of BF3 Complexes with Diethyl Ether and Tetrahydrofuran, and the Isotopic Exchange of these Complexes with BF3
Authors: Begun G. M. , Palko A. A.
Published: January 2005

The Raman and infrared spectra of BF3·diethyl ether and BF3·tetrahydrofuran have been recorded for both the B10 and B11 compounds. The spectra have been compared to that of BF3·dimethyl ether and tentative assignments of the skeletal vibrations have been made. The isotopic data have been used to calculate theoretical equilibrium constants for isotopic exchange between the complexes and BF3. The calculated values are slightly higher but compare quite well with published values of experimentally determined separation factors.
Radiolysis of Methane
Authors: Ausloos P. J. , Lias S. G.
Published: January 2005

The radiolysis of CD4, as well as of equimolar CH4+CD4 mixtures, has been investigated in the presence of C3H8, C4H10, C6H6, C2H4, argon, krypton, and xenon. The results obtained from the radiolysis of CD4–C3H8–I2 and CD4–C4H10–I2 mixtures indicate that ethyl ions and sec-propyl ions are produced. GC2D5+≧1.0,  Gsec−C3D7+≧0.06.The radiolysis of methane in the presence of C2H4 and C6H6 provided evidence for the occurrence of the process: CH4*→CH2+H2.The G value of this process is approximately equal to unity. An analysis of the ethanes produced in the radiolysis of equimolar CH4—CD4 mixtures in the presence and absence of ethylene provided evidence for the production of methylene radicals in both the gas phase and the liquid phase.
Monte Carlo Study of Coiling-Type Molecules. II. Statistical Thermodynamics
Authors: Wall Frederick T. , Windwer Stanley , Gans Paul J.
Published: January 2005

The statistical thermodynamics of coiling-type polymer molecules has been studied by using non-self-intersecting random walks generated on a tetrahedral lattice by Monte Carlo methods with a high-speed digital computer. By introducing a potential energy of interaction between nonbonded nearest neighbors, one can establish a partition function for the polymer chains so simulated. The changes in free energy, internal energy, and heat capacity are then calculated relative to those for molecules subject to no intramolecular interactions other than excluded volume. Empirical equations are developed for the significant thermodynamic quantities. In particular, it is found that for chains no longer than 120 links, the Helmholtz free energy is given by ΔA/kT=(−0.4129+0.06275N)ξexp(−0.7378ξ),where N is the number of links in the chain and ξ=ε/kT if ε is the potential energy of interaction between nearest nonbonded neighbor pairs. Expressions for ΔE/kT and ΔCv/kT are also derived, but their ranges of applicability are not as wide.
Homogeneous Catalysis of Gas-Phase Atom Recombination. Recombination of H Atoms at High Temperatures
Authors: Benson Sidney W.
Published: January 2005

An analysis is made of the effect of a catalyst C on the rate of recombination of atoms X when C forms a relatively long-lived complex with X. Labeling the energy-rich, nascent complex CX*, the kinetic sequence is X+C⇋ lim baCX*,CX*+M⇋ lim dcCX+M,CX+X→ lim eC+X2.

Using steady states for CX* and CX, the rate of recombination assumes three interesting forms in different limiting cases: (1) Rate ∞ (C) (X)2; (2) rate ∞ (C) (M) (X); (3) rate=ka (C) (X). Case 1 corresponds to a weak complex at high pressures; Case 2 has not been reported. It corresponds to the case of a not-too-weak complex forming at very low total pressures. The last case, 3, corresponds to a very strong complex with a long lifetime. It is shown that this is an easily realized case, and that catalytic efficiencies for it can be very high.

Applying the scheme to H-atom recombination in the temperature range 1500–2500°K and calculating the lifetime of CX* from RRK theory, it is shown that CH3≡(C) may be a very effective catalyst. At 3 mm Hg pressure of (H) and 100 mm Hg of (H2) adding 1 mm Hg of CH4 which forms CH3 could produce a rate of recombination 1000-fold faster than the normal termolecular reaction. Under the same conditions NH3 is about 10-fold slower, C2H2 about 30-fold slower, and H2O about 500-fold slower than CH4.
Derivative Crystal Structures
Authors: Buerger M. J.
Published: January 2005

There exists a class of crystal structures which are derived from others by generalization. These are here designated derivative structures. A special case of derivative structure is the popular ``superstructure.'' The symmetry of a derivative structure is a subgroup of the symmetry of the basic structure. Here the term ``subgroup'' is used in a wider sense than common in mathematical crystallography, and includes subgroups with multiple cells. The methods of finding the derivative symmetries are discussed. There are two important kinds of derivative structures, here designated substitution structures and distortion structures. Substitution structures result when a set of different atoms is substituted for a set of like atoms in the basic structure. For a given kind of substitution, it is possible to predict the cell dimensions of the crystal resulting from the substitution, as well as all the possible symmetries it could have. Examples are cited of the applications of derivative structure theory to several branches of crystallography.
Length Changes of Activated Carbon Rods Caused by Adsorption of Vapors
Authors: Haines R. S. , McIntosh R.
Published: January 2005

The length variations of two zinc chloride activated carbon rods caused by the adsorption of several vapors are reported. The relationship between percent extension of the rod and calculated spreading pressure of the adsorbed film suggested by Bangham has been tested. The relation agrees well with experiment for organic vapors above about ⅓ saturation of the monolayer capacity. It does not agree in the low adsorption region nor along the desorption branch of the water isotherm. A marked contraction of the rod below its original length has been noted when water is desorbed, and this contraction may be considered as a proof of the establishment of concave menisci in the capillaries along the desorption branch.
Studies on Aging of Precipitates and Coprecipitation XXXIX. Low Temperature Conductivity of Silver Bromide
Authors: Shapiro I. , Kolthoff I. M.
Published: January 2005

The following expression is proposed for the electrical conductivity of silver bromide χ=(Ae−W/2kT+KS)e−U/kT,in which S is the magnitude of the active surface. When Ae−W/2kT≫KS the high temperature kind of conductivity predominates. In the opposite case the low temperature kind of conductance predominates. Conductivity-temperature curves of fresh (large S) and well-aged (small s) silver bromide have been determined. In agreement with theoretical expectations it is found that χ=3.0×105e−18,000/RT+Aie−8300/RTin which Ai varies in proportion to the active surface of the product. A pellet prepared from freshly precipitated silver bromide was found to have about 500 times as large a conductance as a pellet prepared from the fused product. At a given temperature the following relation exists between χ and the pressure p applied to the pellet: dlnχ/dp=−k. The value of k increases with decreasing active surface and with increasing temperature. The temperature effect is accounted for by the contribution of the active surface.
Dielectric Behavior of Solutions of Electrolytes in Solvents of Low Dielectric Constant. II. Dielectric Absorption
Authors: Sharbaugh A. H. , Eckstrom H. C. , Kraus C. A.
Published: January 2005

The dielectric losses in solutions of salts in several low dielectric constant solvents are studied as a function of frequency and concentration, using the calorimetric method. The results are interpreted according to the Debye theory, and critical frequencies, molecular radii, and dipole moments are evaluated wherever feasible. Solutions of tri-isoamylammonium picrate in benzene and diphenylmethane behave as a monodisperse system having a single well-defined polar structure relatively independent of concentration. Corresponding solutions of tetra-n-butylammonium thiocyanate, in contrast, show a marked departure from theoretical behavior for a monodisperse system, having a broad distribution of relaxation times and a high degree of association strongly dependent on concentration. Di-n-butyldioctadecylammonium thiocyanate shows monodisperse behavior at low concentrations, with more physically and electrically different polar bodies appearing as the concentration is increased. These results are in good agreement with polarization, conductance, and cryoscopic measurements for these systems.
Kinetics of the Photolysis of Methyl Iodide and the Hydrogen Halides II. Photolysis of Methyl Iodide in the Presence of Iodine and the Hydrogen Halides
Authors: Williams Russell R. , Ogg Richard A.
Published: January 2005

The photodissociation of methyl iodide by light of λ2537A has been utilized as a source of methyl radicals for a study of their subsequent reactions with iodine and the hydrogen halides. The observed rate of methane formation has been used to evaluate the ratio of rate constants for the following reactions: CH3+HX→CH4+XCH3+I2→CH3I+Iwhere X represents Cl, Br or I. The reaction with hydrogen chloride has been found to be complicated by the unequal yield of methane and iodine, and possible explanations of this phenomenon have been considered.
The Mechanism of Processes Initiated by Excited Atoms III. Photo-Sensitized Hydrocarbon Reactions
Authors: Laidler Keith J.
Published: January 2005

The photo-sensitized reactions of the hydrocarbons are discussed in terms of the following reaction scheme, in which A* indicates the photo-sensitizing atom and MH2 the hydrocarbon: A*+MH2→A+MH+H,A*+MH2→A+MH2*,MH2*+MH2→2MH2,MH2*→M+H2,MH2*→MH+H.The first and fifth reactions are followed by polymerizations. Expressions for the quenching rate, the rate of formation of M, and the rate of formation of polymer, are obtained in terms of the original rate constants, and a number of special cases of practical interest are treated. The relative rates of the reactions are discussed with reference to the experimental data, particular regard being paid to the energy relationships, the general kinetic behavior, and the influence of temperature. Evidence is adduced in favor of the following: (1) the strength of the C–H bond in ethylene is about 100 kcal., (2) there is a triplet-excited state of acetylene with an excitational energy of 10–30 kcal., (3) conversion of a large amount of electronic energy into vibrational energy proceeds with difficulty, the process taking place much more readily when some of the energy can be taken up as electronic energy of the colliding molecule.
Note on a Form of the Secular Equation for Molecular Vibrations
Authors: Wilson E. Bright
Published: January 2005

By starting with the Hamiltonian form of the equations of motion, the problem of the small vibrations of a polyatomic molecule can be solved with the aid of a secular equation twice the usual size. This equation, however, is readily adapted to solution by electrical circuits and has the important advantage of having as elements the force constants and inverse kinetic energy coefficients (``G'' matrix elements) directly. The force constant matrix elements occupy one off-diagonal corner of the secular equation, the G matrix elements are in the other off-diagonal corner, the circular frequencies (2πν) appear on the principal diagonal, and all other elements are zero.
Simple Potential Functions for HF and [F–H··F]−
Authors: Davies Mansel
Published: January 2005

Calculations based on an electrostatic model have been made of the stabilizing energy in [F–H··F]−. The terms used have first been tested on the HF molecule and the distortion of the latter in the bifluoride ion is estimated. The calculated value of —ΔU for [F–H··F]− is 47.3 kcal. per g ion, in satisfactory accord with thermochemical estimates.
Infra-Red Spectrum and Depolarization Factors of the Raman Lines of Spiropentane and the Raman and Infra-Red Spectra of 1,1-Dimethylcyclopropane,1 1-Methylcyclobutene, and Methylenecyclobutane
Authors: Cleveland Forrest F. , Murray M. J. , Gallaway W. S.
Published: January 2005

The infra-red absorption spectrum in the region 700–4000 cm−1, both for the liquid and for the gas at various pressures, and precise values for the depolarization factors of the Raman lines of spiropentane are reported. Infra-red and Raman frequencies, estimated relative intensities, and qualitative depolarization data are reported also for 1,1-dimethylcyclopropane. Selection rules for the two hydrocarbons are discussed, and it is shown that the observed numbers of Raman frequencies are not inconsistent with the structures D2d and C2v for the spiropentane and 1,1-dimethylcyclopropane, respectively. In addition, Raman and infra-red data are included for the isomers, 1-methylcyclobutene and methylenecyclobutane. Tentative assignments of the fundamentals are made for each of the four hydrocarbons.
Statistical Mechanics of Multimolecular Adsorption. III. Introductory Treatment of Horizontal Interactions. Capillary Condensation and Hysteresis1 a
Authors: Hill Terrell L.
Published: January 2005

The elementary treatment of interactions and first order phase changes in localized and mobile monolayers is reviewed. Calculations on multimolecular adsorption and capillary condensation, which take into account horizontal interactions in an approximate manner, are presented. Several other topics are discussed briefly, including the quasi-chemical method and reversible hysteresis. It is suggested, on the basis of the capillary condensation calculations, that reversible hysteresis involves the use of metastable portions of the adsorption isotherm. The theory predicts, in agreement with experiment, that the adsorption curve should be below the desorption curve.
Hydrodynamic Properties of Sea Water at the Front of a Shock Wave
Authors: Richardson J. M. , Arons A. B. , Halverson R. R.
Published: January 2005

The Rankine-Hugoniot relations have been applied to appropriate equation-of-state data in order to calculate the propagation velocity, particle velocity, enthalpy increment, Riemann function, etc. at shock fronts of various amplitudes in sea water. One set of tables provides values over a wide pressure range (up to about 80 kilobars) and is principally intended for use in conjunction with theories of propagation of shock waves originated by underwater explosions. A second set of tables contains values which are closely spaced up to pressures of 14 kilobars. These are calculated with somewhat greater precision and are intended for use in connection with experimental measurements of particle and propagation velocities, etc.
The Mercury (3P1) Photo-Sensitized Hydrogenation of Ethylene
Authors: LeRoy D. J. , Kahn Allan
Published: January 2005

The mercury photo-sensitized hydrogenation of ethylene has been investigated over the temperature range 42°C to 320°C. At 200°C and lower, the results are in relatively close agreement with those of Jungers and Taylor. The activation energy of the reaction, 2C2H5=C2H6+C2H4, is estimated to be ≥ 1.2 kcal. per mole. Above 200°C ethane formation increases rapidly, corresponding to an activation energy ≥ 10.5 kcal. per mole for the reaction C2H5+H2=C2H6+H. The small amount of polymerization was not affected by temperature.
The Experimental Determination of the Intensities of Infra-Red Absorption Bands. III. Carbon Dioxide, Methane, and Ethane
Authors: Thorndike A. M.
Published: January 2005

The absolute intensities of the chief infra-red absorption bands of carbon dioxide, methane, and ethane have been determined experimentally to be (in cycles per centimeter at N.T.P.): Carbon dioxideMethaneEthane670 cm−1 band:560×10101306 cm−1 band:450×1010 820 cm−1 band:  73×10102350 cm−1 band:8600×10103020 cm−1 band:900×10101450 cm−1 bands:  230×10102950 cm−1 bands:2200×1010These results are in satisfactory agreement with available data on infra-red dispersion and atomic polarization. They may be interpreted in terms of dipole moments, μ′, of bonds between vibrating atoms, and their rates of change with internuclear distance, ∂μ′/∂r. When this is done for the CH bond, however, unexpected variations in these quantities are found for the different vibrations and molecules studied. The average values are about μ′=0.4×10−18, ∂μ′/∂r=±0.6×10−10. For the CO bond the values are considerably larger.
A Note on the Relation between Entropy and Enthalpy of Solution
Authors: Rice O. K.
Published: January 2005

The relation between entropy and enthalpy of solution for a series of non-polar solutes in a given non-polar solvent is discussed. It is considered that solution of a gaseous solute, without changing its concentration on going from gas phase to liquid solution phase, does not change its own entropy, all change of entropy being referred to the solvent. The entropy of the solvent changes because of surface effects around the solute molecules and a kind of long-range order introduced by the solute molecules. Two extreme cases are considered, (1) the case of an ideal solution, and (2) the case of a solute of hard attractionless spheres. The difference in entropy of solution between these extreme cases can be estimated. It can also be estimated by extrapolation from the experimental data on the entropy and enthalpy of solution, and these two estimates agree in order of magnitude. The fact that the relation between entropy and enthalpy of solution is linear is also shown to be a reasonable expectation, and effect of changing solvent as well as solute is considered. The groundwork is thus laid for a qualitative understanding of this relation between entropy and enthalpy of solution.
Motions of Molecules in Condensed Systems III. The Infra-Red Spectra for Cyclohexane Solid II, Solid I, Liquid and Vapor in the Range from 3 to 15μ
Authors: Carpenter Gene B. , Halford Ralph S.
Published: January 2005

Infra-red spectra are compared throughout the interval from 650 to 3300 wave numbers for the same amount of cyclohexane when it exists separately as vapor at 20°, liquid at 10°, and solid I at 3°C, likewise in the intervals from 700 to 1600 and 2500 to 3300 wave numbers when it exists as solid I at −75° and solid II at −100°C. The four spectra obtained with the condensed phases are quite similar and differ only slightly from the one for the vapor. These results contrast sharply with ones reported previously for a similar study of benzene and indicate that there is a greater semblance of order in liquid cyclohexane than in liquid benzene. The spectra are consistent with, but yield no constructive evidence to confirm or deny the notion that molecules of cyclohexane are able to rotate freely in solid I. Developments attributable to intermolecular forces, although not spectacular, contain new information about the numbers and positions of bands which may prove useful toward assigning frequencies to normal modes of vibration in the isolated molecule of cyclohexane. The results of this study do not contradict any of the principles set forth in the first paper of this series.
Infra-Red Absorption Spectra of Some Octenes
Authors: Rasmussen R. S. , Brattain R. Robert , Zucco P. S.
Published: January 2005

The infra-red absorption spectra in the 2μ to 15μ region of 1-octene, 2-octene, 3-octene, 4-octene, 2-methyl−1-heptene, 6-methyl−1-heptene, and 2,4,4-trimethyl−1-pentene are given. Salient features of the spectra are discussed.
Physical Properties and Cation Arrangement of Oxides with Spinel Structures I. Cation Arrangement in Spinels
Authors: Verwey E. J. W. , Heilmann E. L.
Published: January 2005

By means of a detailed x-ray study of a large number of oxides having a spinel structure, it has been established whether they crystallize in the ``normal'' spinel-type structure, XY2O4, or in the ``inversed'' type of structure, Y(XY)O4, discovered by Barth and Posnjak. Certain rules can be derived which are also applicable to more complicated spinels or to solid solutions of different spinel oxides. Madelung constants have been calculated for different spinel types in order to investigate their stability on the basis of an ionic concept of the chemical bond (Born's lattice theory). The experimental results are only partially explainable on this basis. All exceptions to the electrostatic principles can be understood by assuming that Fe3+, Ga3+, In3+, Zn2+, and Cd2+ favor a configuration having the coordination number 4, because of a considerable covalent contribution to the chemical bond for that configuration.
The Contribution of Restricted Rotation to Electron Scattering by Gases
Authors: Karle J.
Published: January 2005

Several formulae have been derived expressing the contribution to the intensity of electron scattering of restricted rotation in the vapors of ethane, ethylene, biphenyl, and their derivatives. The probability distribution of the restricted rotator about its axis of rotation is expressed in terms of the barrier height, V0. It has, therefore, been possible to evaluate the effect of barriers of known magnitude on scattering patterns. The possibility of evaluating the potential barrier using electron diffraction is discussed.
The Interpretation of Electron Diffraction Patterns from Hydrocarbon Films
Authors: Karle J. , Brockway L. O.
Published: January 2005

The theoretical expressions previously derived for the scattering of electrons by oriented hydrocarbon chains have been extended and applied to the calculation of characteristic diffraction patterns. These patterns are analyzed to form a basis for obtaining information about the molecular orientation. For the long chain molecules, the azimuthal direction, and the declination from the vertical may be determined independently. The orientation of the hydrocarbon chain about its own axis is less easily established, since it is determined only from the intensity distribution within the separate diffraction orders. When the declination is sufficiently large, randomness in the azimuthal directions is distinguished by the crossed-line pattern obtained. Randomness in the declination from the vertical may be estimated from the irregular spacing of the intercepts of the crossed lines. Quantitative intensity data would permit a more precise study of the angular distribution of the declination, and also of the orientation of the hydrocarbon chain about its own axis.
Infra-Red Spectra of Monomeric Formic Acid and Its Deuterated Forms. II. Low Frequency Region (2200–800 cm−1)
Authors: Williams Van Zandt
Published: January 2005

High resolution infra-red studies have been made of monomeric HCOOH, HCOOD, DCOOH, and DCOOD in the region 2200 cm−1 to 800 cm−1. Consideration is given to the possibility of the existence of a trans-form of the molecule. The bands observed are not sufficiently regular in appearance or absorption frequency to permit assignment of vibrational modes without further knowledge of the spectra.
A Raman Apparatus for Quantitative Polarization Measurements
Authors: Crawford Bryce L. , Horwitz William
Published: January 2005

An apparatus for quantiative measurement of the depolarization factors of Raman lines is described. It is a modification of Edsall and Wilson's method, using polaroid cylinders. Short exposure times result from the use of eight exciting lamps. No apparatus corrections are needed. Alignment is not overly critical. Performance is reported on the Raman lines of CCl4, CHCl3, and C6H6.
On the Concentration Dependence of the Rates of Sedimentation and Diffusion of Macromolecules in Solution. Preliminary
Authors: Singer Seymour J.
Published: January 2005

The concentration dependence of the osmotic pressure, rate of diffusion, and sedimentation velocity for solutions of high molecular weight solutes, on the basis of certain assumptions, have been shown to be interrelated. Experimental confirmation, however, has been lacking. Preliminary data are given in this article which satisfy these interrelationships, with fractions of cellulose acetate in acetone; however, more cooperative osmotic pressure, diffusion, and sedimentation experiments on a variety of well-defined systems are necessary to confirm the hypothesis.

If and when this additional confirmation is produced, the assumptions involved in the hypothesis may be considered correct; these are: (1) that the frictional coefficient in diffusion is the same (barring special cases of orientation during transport) as the frictional coefficient in sedimentation; and (2) that the driving force of diffusion is the gradient of the free energy of dilution of the system.

For solutions with no heat of mixing, the slight dependence of the diffusion constant on concentration has its molecular basis in the fact that the size and shape of the molecules affect the thermodynamic and hydrodynamic contributions to the variation of the diffusion rate to a comparable extent, and these contributions partially cancel one another. This is quantitatively so in the simple case of rigid spheres in an athermal solution.
The Entropy of Mixing of Binary Liquid Mixtures
Authors: Wood Scott E.
Published: January 2005

Three factors which may contribute to the excess entropy of mixing of binary solutions have been explored. These are the relative volumes of the molecules, the spatial distribution of the molecules about a given reference molecule, and the lack of randomness of the orientational distribution of the molecules about a reference molecule. Of these, the spatial distribution, which depends upon the energy of mixing, is the smallest. It yields a negative value for the excess entropy and becomes zero at infinite dilution. The effect of differences in the volumes of the molecules of the components is positive and may be appreciable. The greatest effect is obtained from the orientational distribution. An estimation of the lack of randomness in this distribution for the pure components is obtained from the differences of the entropies of evaporation of the components and that of argon compared under corresponding conditions. This difference is positive and is comparable, at least in order of magnitude, to the observed partial molal excess entropy of mixing at constant pressure and at infinite dilution for the six binary mixtures composed of benzene, carbon tetrachloride, cyclohexane, and methanol. The contribution of the change in the orientational distribution of the components to the partial molal excess entropy at infinite dilution is then considered to be caused by two effects, one in which the orientational distribution of the solute becomes completely random when dissolved in a solvent at infinite dilution and the other in which the orientational distribution of the solvent is changed by the substitution of a solute molecule for a solvent molecule. The individual behavior of each solvent is very evident and is consistent with its molecular structure.
Intermolecular Forces and Energies of Vaporization of Liquids
Authors: Benson Sidney W.
Published: January 2005

By using a ``smoothed potential'' model for the liquid state and assuming isotropic, homogeneous expansion with temperature which involves no change in coordination, it is shown that it is possible to reduce the expression for the configurational energy of the liquid to a function of a single parameter, the density. If the intermolecular forces can be put into a polynomial form then the expression for the configurational energy can be factored, resulting in an algebraic equation of the form: Ec=−B1D2−B2D8/3−B3D−10/3+B4D4in which D is the molar density and the B's are constants independent of temperature. For the distances occurring in liquids, the last three terms can be either dropped or combined with the first, leaving as an approximation: Ec=ADx/3. The energy of vaporization is given by: Ev=A(D1x/3—Dgx/3 ). Values calculated from this last equation show excellent agreement with experimental values for a large number of both normal and ``abnormal'' liquids. Values of x=5 or 6 both work, the latter being better up to the critical temperature.
Chemical Forms Assumed by C14 Produced by Neutron Irradiation of Beryllium Nitride
Authors: Yankwich Peter E.
Published: January 2005

The nature of the radioactive compounds formed in the production of C14 by neutron irradiation of beryllium nitride has been investigated. Solution of the irradiated powder gave activities corresponding to methane, carbon monoxide, carbon dioxide, hydrogen cyanide, methanol, and formic acid. Formaldehyde was not found. The distribution of activities is not affected by the acidity of the solvent. The results are considered in the light of earlier work.
On the Mass Spectra of Hydrogen and Deuterium
Authors: Stevenson D. P.
Published: January 2005

On the basis of reasonable assumptions with regard to the probabilities of electron-impact induced transitions of hydrogen and deuterium, it is calculated that the relative intensity of H+ in the mass spectrum of hydrogen should be 2.3 times greater than that of D+ in the mass spectrum of deuterium for ionization by electrons of less than 35-volt energy. This value is compared with experimental values 2.8 (22-v energy), 1.5 (30-v energy), 1.9 (50-v energy), and 2.2 (100-v energy).
The Size and Vibration Frequency of the Excited Benzene Molecule
Authors: Griffing Virginia
Published: January 2005

It is shown that the change in size and vibration frequency of a polyatomic molecule upon electronic excitation can be calculated if the excitation energy is known as function of the distance. This is applied to benzene, for which this function is calculated both with the Heitler-London-Slater-Pauling method and the molecular orbital method. Upon comparison with experiment, it is found that both methods give the right sign and order of magnitude for the change in size, but the wrong sign for the change in frequency.
The Rate of Adsorption of Phosgene and Chloropicrin on Charcoal
Authors: Dole Malcolm
Published: January 2005

Making use of a relationship between the adsorption rate constant and the maximum slope of the effluent concentration-time curves derived from the rate equation of Bohart and Adams, it has been possible to estimate an absolute rate of adsorption of phosgene and chloropicrin on charcoal from the experimental data of Dole and Klotz. It is shown that diffusion to the most accessible part of the charcoal surface will occur faster than the observed rate, but more slowly to the least accessible surface areas. Calculated rates of adsorption using the statistical equations of Glasstone, Laidler, and Eyring and of Temkin are also of the correct order of magnitude when plausible assumptions are made concerning the nature of the activated state. It is concluded that both diffusion and surface reaction mechanisms must be postulated to gain a complete understanding of the adsorption rate of the two gases, but with diffusion being less important in the case of phosgene.
Low Temperature Transport Properties of Gases. I. Helium
Authors: Amdur I.
Published: January 2005

Values have been computed for the viscosity, thermal conductivity, and coefficient of self-diffusion of gaseous helium for temperatures below 200°K by application of classical scattering theory within angular regions where diffraction effects are absent. Values of classical total collision cross sections are obtained which are used to evaluate classical cross sections for viscosity, thermal conductivity, and self-diffusion appropriate to a Maxwellian gas. Numerical values of the transport properties are obtained by substitution of the appropriate classical cross sections into the exact transport property formulas of Chapman and Enskog.

In the region 200° — 14°K, the average absolute deviations between calculated and experimental values are 1.9 percent for viscosity and 4.6 percent for thermal conductivity. Extrapolation of calculated viscosity values to 1.64°K appears to be justified on the basis of agreement with experimental values. It cannot be stated that similar extrapolation in the case of thermal conductivity is valid because of possible uncertainties in the experimental values between 3.95° and 1.62°K. Values of the self-diffusion coefficient have been calculated between 200° and 5°K, but experimental values are not available for comparison.
Solubilization by Solutions of Long-Chain Colloidal Electrolytes
Authors: Stearns Richard S. , Oppenheimer Hans , Simon Eric , Harkins William D.
Published: January 2005

Increase in the concentration of a soap or other detergent does not increase the solubility of an oil above that in water until the critical concentration for the formation of micelles (cmc) is attained. Above this the solubility, designated as solubilization, increases and, in general, more rapidly as the soap concentration increases; i.e., per mole of soap the solubilization is greater in a 25 percent than in a 5 percent soap solution. For a homologous series the volume of oil solubilized at a constant temperature is to a first approximation inversely proportional to the molar volume. The polarity and shape of the molecules solubilized also play a role. Salts increase the extent of the solubilization; at low concentrations to an extent which may be accounted for by the increase in micellar area resulting from the depression of the cmc by the salt. At higher soap concentrations the increase in solubilization is greater than can be accounted for in this way.
Statistical Mechanics of Binary Mixtures
Authors: Miller A. R.
Published: January 2005

The possibility of specifying both the enumeration of the complexions of an assembly and the evaluation of its configurational energy in terms of the numbers of closest neighbor pairs of sites of various kinds, without introducing parameters explicitly to specify the occupation of individual sites, is considered. The formula obtained on such a basis by Alfrey and Mark is examined. Their work depends on an assumption which at first sight appears plausible. Furthermore, if this assumption could be justified, it would imply that the quasi-chemical equation, which has been introduced in the theory of regular assemblies as an ad hoc assumption, could be derived from the Boltzmann equilibrium law and the elementary formulas of algebraic combinations. If a pair of closest neighbor sites of which one is occupied by a molecule of species i and the other by a molecule of species j is called an i—j pair, then it is shown that the assumption made by Alfrey and Mark is equivalent to neglecting the restrictions on the free allocation (amongst the ½zN pairs available in all) of pairs of different kinds which are inherent in the interconnections of an assembly of interacting particles. It is concluded, therefore, that the assumption in question is unjustified and leads to an incorrect result, and that consequently the quasi-chemical equation is correctly introduced as an ad hoc assumption.
Determination of the Ranges of the Fission Fragments Emitting Delayed Neutrons. Chemical Identification of the 4.51-Sec. Delayed Neutron Activity
Authors: Sugarman Nathan
Published: January 2005

The ranges of the fission fragments leading to delayed neutron emission have been determined by absorbing the fragments in Al and counting the penetrating activity. The delayed neutron activities and their corresponding ranges in Al corrected for source thickness are: 4.51 sec., 4.05±0.03 mg Al/cm2; 55.6 sec., 3.98±0.06 mg Al/cm2; 1.52 sec., 3.63±0.12 mg Al/cm2; 22.0 sec., 3.21±0.04 mg Al/cm2. Comparing the range of the 4.51-sec. activity with that of the 55.6-sec. Br, one finds that mass assignments possible for the 4.51-sec. activity are 86 to 90. Similarly, the range of the 1.52-sec. activity is compared to that of the 22.0-sec. I, and the possible mass assignments found are 129 to 135.

Chemical separation of Br from irradiated uranyl nitrate resulted in the identification of the 4.51-sec. activity as an isotope of Br.
On a Method of Correcting for Incomplete Thermal Isolation in Measurements of Small Heat Capacities
Authors: Aston J. G. , Szasz G. J.
Published: January 2005

The treatment originally given by Keesom and Kok is simplified in such a manner as to make it applicable to heat-capacity measurements in which the temperature of the system is known only before and after heating.
Contribution to the Study of Electronic Spectra of Bent Triatomic Molecules
Authors: Duchesne Jules , Rosen B.
Published: January 2005

The electronic absorption spectra of the SO2, SeO2, and TeO2 molecules have been studied under widely varied experimental conditions. The vibrational analysis of the ultraviolet absorption region of SO2 with center of gravity near 2000A reveals that it is formed by at least two electronic systems with the following vibrational constants: System α1···ν0=42,170 cm−1,  ν1′=963 cm−1,  ν2′=379 cm−1,  x′ν2′=2 cm−1.System α2···ν0=44,236 cm−1,  ν1′=775 cm−1,  ν2′=375 cm−1.The presence in the same region of a third electronic system, with ν2′=360 cm−1 and ν1′=845 cm−1, seems highly probable.

The character of the vibrational structure of the band systems and a preliminary analysis of the rotational structure of several bands have enabled us to obtain some information about the molecular structure of the excited states.

The vibrational analysis of the c-system of SeO2 in the visible, and the TeO2 bands in the visible and ultraviolet, have enabled us to correlate the electronic states of the three similar molecules.
Restricted Rotator Thermodynamic Properties from the Old Quantum Theory
Authors: Halford J. O.
Published: January 2005

Accurate partition functions and free energies are calculated for the hindered internal rotator from the old quantum theory based upon the quantization rule of Wilson and Sommerfeld. The description of the system is incomplete and the energy levels may even be incorrectly placed, but the partition functions are surprisingly close to those now accepted as correct. In the course of the development the lowest energy state of the harmonic oscillator turns up in its correct position at the half-quantum level.
Theory of the Increase in Rigidity of Rubber during Cure
Authors: James Hubert M. , Guth Eugene
Published: January 2005

The rigidity of rubber, considered as a network of flexible molecules with Gaussian configuration functions, can be calculated for a particular sample if one is given a complete description of the molecular network or certain types of statistical description. In particular, it is sufficient to know the distribution of lengths and vector-mean extensions of the segments of the network, or only the latter distribution if it is of Gaussian form. The assumption that the vector-mean extensions have a Gaussian distribution corresponds to a similar postulate in the theory of Wall, and has been applied to a simplified network theory by Flory. In the complete theory it leads to calculation of the same proportionality between the rigidity of the material and the number Ga of segments, per unit volume, in the ``active'' part of the molecular network. However, consideration of the process of cure shows that this assumption cannot be expected to be correct, though it does lead to results of the right order of magnitude. An alternative approach to the problem is based on a study of the increase in rigidity of the material as cure proceeds. It uses a more realistic picture of the process of cure than those hitherto employed, and uses Gaussian distribution functions only where they can be logically justified. The final result is of the same form as that given by the previous theory, except that Ga is replaced by Ba, the number of bonds formed within the molecular network during cure. Since Ba is smaller than Ga by a factor of about two or more, the improved theory leads to the prediction of somewhat lower rigidities per bond formed. Available experimental results of Flory on Butyl rubber vulcanizates do not appear to give an adequate check on the quantitative features of the theory.
Chemical Properties of Astatine. I
Authors: Johnson G. L. , Leininger R. F. , Segrè E.
Published: January 2005

This work is a report on studies of the chemistry of astatine on a tracer scale, using the various methods of tracer chemistry. A general discussion of preparation of materials and analytical methods is included. The properties of astatine and its solutions as they appear in work on a tracer scale are discussed. Migration experiments show that astatine when ionized in aqueous solution is negatively charged. Electro chemical, solvent extraction, and carrying studies are presented.

In general, (a) elemental astatine is extractable by organic solvents; (b) the − 1 state may be prepared by powerful reducing agents; and (c) at least two positive oxidation states exist.
The Vibration-Rotation Mechanics of the Allene Molecule. Part I. Classical Vibration Problem
Authors: Herman Robert C. , Shaffer Wave H.
Published: January 2005

Symmetry coordinates are set up from the standpoint of group theory for describing the normal modes of oscillation of the allene molecular model in such a manner that maximum factorization of the secular determinant is accomplished. The cubic and quartic portions of the anharmonic potential function are derived, and the components of vibrational angular momentum are set down. The complete valence-type potential function is discussed. Explicit relations are derived between the force constants occurring in the secular determinant and the physical valence force constants.