bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mechanism of Reactions Involving Excited Electronic States The Gaseous Reactions of the Alkali Metals and Halogens
Authors: Magee John L.
Published: January 2005

In many of the reactions of the alkali metals with the halogens the reacting system changes from a homopolar to a polar state, or vice versa. The possibility of a restriction on this change is considered, and it is concluded that there will be a serious restriction only for some of the atomic reactionsM+X→MX, which are of little importance. The crossing points between the polar and homopolar states for the reactionsM2+X→MX+M M+X2→MX+X are drawn in so close that the interaction is large enough to insure transition. Due to the threefold degeneracy of the initial state of b (which arises because X is in a P state) this reaction has the possibility of leading directly to the excitation of the M atom which is formed. The nature of the potential surfaces for this process are considered. The process first suggested by Polanyi, the excitation of M atoms by vibrationally excited MX molecules, is discussed. This process is possible because of a crossing of the two lowest polar states for the M2X system. These two surfaces cross for a certain isosceles triangular configuration. Reacting systems thus easily go from the lowest to the second state in this region.
The Fundamental Frequencies of Certain Trihalomethanes
Authors: Glockler G. , Leader G. R.
Published: January 2005

The Raman spectra of dibromochloro-, bromo-dichloro-, dichlorofluoro-, chlorodifluoro-, dibromofluoro- and bromochlorofluoro-methane have been studied. Their fundamental frequencies have been correlated and systematized. Simple graphical means were used to predict the Raman frequencies of CHBrF2 and CHF3. It was found that the C—X bond will show a ``characteristic'' frequency whenever the halogen X is the only and lightest of this type in a halomethane.
Theory of the Transition in KH2PO4
Authors: Slater J. C.
Published: January 2005

Potassium dihydrogen phosphate contains phosphate groups connected by hydrogen bonds. Different possible arrangements of the hydrogens result effectively in different orientations of the (H2PO4)— dipoles. Since these have the lowest energy when pointing along the axis of the crystal, there is a tendency toward spontaneous polarization along this axis, resulting in the well-known transition, similar to Rochelle salt, with polarization below the Curie point. The theory of this transition is worked out, using statistical methods to count the number of arrangements of hydrogens consistent with each total polarization of the crystal, and deriving the free energy. It is found that the theory predicts a phase change of the first order, with sudden transition from the polarized state at low temperature to the unpolarized state at high temperature, rather than the lambda-point transition or phase change of the second order which is observed. However, the observed transition is confined to a very narrow temperature range compared to that predicted, for instance, by the Weiss theory, so that it seems as if it might be merely a broadened transition of the first order. It is suggested that the broadening may result from the irregular shifts of transition temperatures of individual domains in the crystal on account of stresses resulting from the large piezoelectric effect and the resulting deformation of the crystal below the transition point. The susceptibility above the Curie point comes out by the theory to be 4.33 times as great as it should according to the Weiss theory, a result which seems to be in general agreement with experiment. The entropy change in the transition is given by the theory as 0.69 unit, somewhat smaller than the observed value of about 0.8 unit. No explanation is suggested for this discrepancy.
Molecular Distribution
Authors: Mayer Joseph E. , Montroll Elliott
Published: January 2005

Various functions, by means of which the distribution of molecules in a system may be described, are defined, and the relations between them are derived. Equations, by means of which these functions may be calculated from a knowledge of the mutual potential energy between pairs of molecules, are also derived. The equations applicable to gaseous systems, which are derived by a development previously used in the theory of condensing systems, enable the calculation of the distribution functions by means of a power series in either the fugacity or the inverse volume. The coefficients of these power series are direct integrals involving the pair potentials between molecules. In condensed systems an alternative procedure is required. The equations then appear in the form of integral equations involving the unknown functions under the integral signs. These equations are not readily solved, due primarily to the difficulties of performing multiple coordinate integrations. By the use of functions involving the probabilities of population of virtual cells, the cell equation frequently used for the calculation of the thermodynamic properties of liquids is derived as a consequence of the method used here. The direct connection between the equations derived in the theory of condensing systems, and in the usual cell approximations, is thus established. The equations derived here, however, permit consistent use of the cell method to arrive at higher approximations. This development may possibly be of value in making numerical evaluations of the thermodynamic functions of liquids.
The Influence of Intramolecular Atomic Motion on Electron Diffraction Diagrams
Authors: Debye P.
Published: January 2005

A discussion of the influence of atomic vibrations and of free or hindered rotations of molecular groups in molecules on their scattering properties. The radial distribution curve is calculated and the results which may be expected from an analysis of this curve are indicated.
Overvoltage and the Structure of the Electrical Double Layer at a Hydrogen Electrode
Authors: Kimball George E. , Glasstone Samuel , Glassner Alvin
Published: January 2005

The theory of absolute reaction rates applied to electrode processes leads to the equation s=(kT/h) exp (−ΔF*/RT) exp (αVF/RT)for the specific rate of discharge of ions. The question arises as to whether V should be the actual potential at the electrode or only the overvoltage. In the case of hydrogen ion discharge, it is found experimentally that the overvoltage should be used. On the other hand, the theory in its simplest form requires V to be the total potential. This paradox can be resolved by postulating the existence of two different electrical double layers at the electrode surface, and two corresponding energy barriers over which the protons must pass. Provided that the barrier nearer the electrode is the higher, the overvoltage is essentially established across this layer, while the variation in equilibrium potential caused by variations in the hydrogen ion concentration of the solution is established across the outer double layer. Since the rate of discharge is determined by the potential difference across the inner double layer, the rate is determined by the overvoltage, and not by the total potential. The nature of these two energy barriers is also discussed. Both barriers may correspond to transfer of protons from water molecule to water molecule, or one may correspond to the actual discharge process in which a neutral hydrogen atom is formed. It does not yet seem to be possible to decide between these two alternatives, either theoretically or experimentally, but it seems most probable that both barriers correspond to proton transfers from water molecule to water molecule.
The Thermal Decomposition of Methyl-n-Butyl Ether
Authors: Magram Sidney J. , Taylor H. Austin
Published: January 2005

The thermal decomposition of methyl-n-butyl ether proceeds in a manner analogous to that of the other ethers. There is no evidence to support the suggestion that it might decompose into methyl alcohol and ethylene by a ring closure through a hydrogen bond. In the first stages of the decomposition about 60 percent of the ether decomposes into CH4 and C3H7CHO and about 40 percent into HCHO, C2H4 and C2H6. The decomposition of the aldehydes occurs at rates greater than that of the ether, probably induced by radicals from the ether. The butyraldehyde yields mainly CH4, C2H4 and CO. First-order constants fall off as the reaction proceeds and also with diminishing pressure. The energy of activation at about 200 mm pressure is 54.0 kcal. and at 100 mm 56.6 kcal. For the reaction inhibited by nitric oxide the energy of activation is about 60 kcal.
The Absorption Spectrum as a Quantitative Test for Mercury Vapor in Air
Authors: Clark K. C. , Oldenberg O.
Published: January 2005

In order to test the mercury vapor content of the air in a laboratory, the absorption spectrum of this vapor is compared with a set of calibration spectra. With a simple apparatus (``medium size'' quartz one-prism spectrograph) vapor pressures far below the toxic limit can be determined.
Thermodynamic Properties of Binary Solid Solutions. Phase Separation
Authors: Lassettre Edwin N. , Howe John P.
Published: January 2005

A previously developed method of calculating the thermodynamic functions of a mixture is further examined. For a lattice which is large in at least two dimensions it is shown that the largest eigenvalue of the fundamental matrix is doubly degenerate over a finite temperature range, and within this range a separation into phases takes place. An approximation to the phase boundary which is valid at low temperatures is obtained.
Analysis of the Near Ultraviolet Absorption Spectrum of Monochlorobenzene
Authors: Sponer H. , Wollman S. H.
Published: January 2005

The absorption spectrum of C6H5Cl at 2750–2400A has been studied in the first order of a 3 m grating spectrograph. The band system corresponds to an electronic transition A1→B1 (monochlorobenzene has the symmetry C2v) with the transition moment lying in the molecular plane perpendicular to the C–Cl bond. In agreement with this assignment to an allowed transition the 0,0 band appears strongly. Several progressions have been found involving various totally symmetrical vibrations. Besides this ``allowed'' part of the spectrum there appear ``forbidden'' bands which are due to the excitation of a non-totally symmetrical vibration of suitable symmetry. This vibration corresponds to the one (εg+ 606 cm—1) whose excitation is responsible for the appearance of the benzene spectrum. The analysis is supported by comparison with the absorption of solid monochlorobenzene at —259°C.
Further Studies on the Oxidation of Nitric Oxide; the Rate of the Reaction between Carbon Monoxide and Nitrogen Dioxide
Authors: Brown F. B. , Crist R. H.
Published: January 2005

The initial rate of the reaction between CO and NO2 from 225°C to 290°C was measured under conditions which precluded the possibility of NO2 decomposition. This study extends the earlier data on the reaction over a 300° temperature interval. The oxidation of nitric oxide at 25°C and at pressures from 0.01 to 0.1 mm of NO was found to be third order over a 3- and 6-fold change in reactants. The CO2 and NO2 production in systems containing NO, CO, and O2 around 150°C was measured under conditions in which the formation of CO2 by the reaction between CO and NO2 was negligible. It is concluded that NO3 is the intermediate needed to correlate this and previous data on reactions involving NO and NO2, and that the rate of the reaction of NO3 with NO is faster than that with CO.

A new apparatus containing greaseless valves capable of handling quantities of products of the order of 10—3 mm, and a method of analysis precise to 3×10—5 mm was devised. Methods to prepare reactant gases of the requisite purity are described.
The Region of Critical Solution of Binary Liquids, Evidence for an Anomalous First-Order Transition in the System Triethyl Amine-Water
Authors: Roberts Louis D. , Mayer Joseph E.
Published: January 2005

The change of fugacity with composition has been investigated in the liquid system triethyl amine-water in the temperature region adjacent to the temperature of critical solution. It has been shown that within experimental error this change is zero for a range of at least 5°C on the one phase side, and for compositions of liquid between 20 and 50 weight percent. This is taken to be evidence for the existence of a range of anomalous first-order transition adjacent to the critical temperature. Values of change of fugacity with composition have been determined sufficiently precisely to be in definite disagreement with simple conclusions drawn from the concept of the continuity of states.
The Entropy of Acetic Acid
Authors: Halford J. O.
Published: January 2005

From third law measurements, vapor pressures and vapor densities, the entropy of the acetic acid monomer at 25° and one atmosphere is 69.4±1.0 e.u. The value 68.7 is calculated from the vapor phase ethyl acetate equilibrium. For a model based upon acetone and approximately representing free rotation the entropy would be 72.7. If there is only a single potential minimum in the hydroxyl group rotational cycle, the large deficiency below the free rotation value is explained without assuming an exceptionally high potential barrier. A brief discussion of the effect of the number of potential minima and their relative depth is appended, and a possible source of error in third law measurements is suggested.
The Compressibilities of Gaseous Mixtures of Methane and Normal Butane. The Equation of State for Gas Mixtures
Authors: Beattie James A. , Stockmayer Walter H. , Ingersoll Henry G.
Published: January 2005

The compressibilities of three gaseous mixtures of methane and normal butane have been measured from 100° to 300°C and from 1.25 to 10 mole/liter (maximum pressure 350 atmos.). The data on these three systems and the two pure hydrocarbons are used to study several methods of combination of constants in the Beattie-Bridgeman equation of state extended to apply to gas mixtures. The best results were obtained with square-root combination for A0 and for c and Lorentz combination for B0; but square root combination for A0 and linear combination for B0 and for c are a fair compromise between accuracy of representation of the data on mixtures and simplicity of expression.
Raman Spectra of Some Ethers Containing One or More Phenyl Groups
Authors: Murray M. J. , Cleveland Forrest F.
Published: January 2005

Raman frequencies, estimated intensities and depolarization factors are listed for n-propylphenyl, n-butylphenyl, ethylbenzyl, n-butylbenzyl and dibenzyl ethers. Intense frequencies characteristic of monosubstituted benzenes whose values were constant in the five ethers are 618(5)0.8, 1001(10)0.1, 1029(7)0.3, 1156(4)0.8, 1176(4)0.8, 1588 and 1604 (6)0.7, 3058(9)0.3. Frequencies characteristic of the C–O–C bond may be those near 440, 900 and 1125 cm—1.
Absorption Spectra of the Chrome Alums at Low Temperatures
Authors: Kraus D. L. , Nutting G. C.
Published: January 2005

Line absorption spectra of thirteen sulfate and selenate chrome alums have been measured at 15–20°K. Pronounced differences in the spectra are attributed to structural differences in the crystals and are related to the size of the anions and the univalent cations. Anomalous behavior on change of temperature is shown by potassium sulfate and ammonium sulfate and selenate alums. Transitions disrupting the lattice and significantly altering the spectrum occur in ammonium chromium sulfate at 81±1°K and in ammonium chromium selenate at 106±5°. Combination of electronic frequencies of Cr+++ with internal oscillations of anions are weak. Combination of lattice vibrations with both upper and lower electronic states of Cr+++ are found. Bands are observed in all the alums shifted about 330, 570 and 800 cm—1 to higher frequencies than the electronic absorption lines. These are thought due to photo-excitation of a nonhomopolar complex, probably Cr(H2O)6+++. Repetition of the electronic multiplet and associated vibrational structure at some of these higher frequencies is found in several of the alum spectra.
The Differential Diffusion Constant of Calcium Chloride in Aqueous Solution
Authors: Hollingshead E. A. , Gordon A. R.
Published: January 2005

The differential diffusion constant for calcium chloride in aqueous solution has been measured for concentrations ranging from 0.0025 to 0.5 mole per liter and for temperatures from 15° to 35°C. The relation connecting the diffusion constant at a finite concentration with that at infinite dilution, k=k0(1+c∂ ln f/∂c)(η0/η), which holds for moderate concentrations for several 1 — 1 electrolytes, is valid for this salt only up to 0.01 mole per liter; the corresponding value of k0 is about 1.5 percent less than that computed from the ionic mobilities by the Nernst relation. The activation energy of diffusion for a given concentration decreases with rising temperature as is customary; for a given temperature, however, it decreases with increasing concentration in dilute solutions, and finally becomes independent of concentration.
The Entropy of Formic Acid. The Heat Capacity from 15 to 300°K. Heats of Fusion and Vaporization
Authors: Stout J. W. , Fisher Leon H.
Published: January 2005

The heat capacity of solid and liquid formic acid has been measured from 15 to 300°K. The melting point is 281.40°K (0°C=273.10°K). The heat of fusion is 3031 cal. mole-1 and the heat of vaporization at 298.10°K is 4754 cal. mole-1. (1 mole=46.0260 grams.) The vapor pressure at 298.10°K is 4.31 cm of mercury. From the third law of thermodynamics and the calorimetric data the entropy has been calculated. To the value obtained from the calorimetric measurements an entropy of R/2 ln 2, due to the random orientation of hydrogen bonds in the solid which has been predicted by Pauling, has been added. This gives 31.51 cal. deg.-1 mole-1 for the entropy of the liquid at 298.10°K and 47.46 for the entropy of 46.0260 grams of gas, P=4.31 cm, in equilibrium with the liquid at 298.10°K. These are the values that should be used in thermodynamic calculations.
Spectroscopic Evidence for Hydrogen Bonds: Comparison of Proton-Attracting Properties of Liquids. III
Authors: Gordy Walter , Stanford Spencer C.
Published: January 2005

This is the third paper of a series in which the proton-attracting powers of different liquids are compared by a measurement of the perturbation they produce on the OD vibrational band of CH3OD. Data showing the absorption of the OD group of CH3OD in seventy-seven different solvents are given in the present paper, in a table listing positions of the band and shifts from the position of the unperturbed OD absorption band. Ketones, aldehydes, organic and inorganic esters, ethers, nitriles, amines, glycols, amides and a few other types of compounds were studied. Many interesting variations due to differences in structure were detected. With certain exceptions a linear relation was found to exist between the logarithms of the basicity constants of the solvents as measured in water solution and the shifts they cause in the OD band. A close correlation was observed between the effects of these solvents on the OD band of heavy methyl alcohol and their solubilities and heats of mixing with certain other compounds. No correlation was evident between the absorption data and the dielectric constants and dipole moments of the solvents. A relationship was found to exist between the proton-acceptor power of a given atom and the electro-negativities of the atoms adjacent to it in the molecule.
Studies on Glass XVII. The Thermal Conductivity of Glassy and Liquid Glucose
Authors: Greene Earnest S. , Parks George S.
Published: January 2005

The coefficients of thermal conductivity of glassy and liquid glucose have been measured between —77 and +80°C with a concentric cylinder apparatus. The results show no irregularity or significant change within the ``transition'' or softening region of the glass.
The Temperature Coefficient of the Conductance of Potassium Chloride in H2O—D2O Mixtures
Authors: LaMer Victor K. , Nachod Frederick C.
Published: January 2005

The temperature dependence of the equivalent conductance Λ of 0.02 molar potassium chloride has been studied at 5, 25, and 45°C as a function of the deuterium content of the solvent. The new data for Λ at 5 and 45°C exhibit the same sag type of curve when plotted against the deuterium fraction, FD, of the solvent as observed previously by LaMer and Baker for 0.01M KCl at 25°C. Although the equivalent conductance in pure D2O decreases to 83 percent of the H2O value, the Walden product (Λη) of equivalent conductance Λ multiplied by relative viscosity of the solvent η remains almost constant. It increases slightly but linearly with FD from 138.5 to 141.1 at 25°C. Similar behavior is noted at 5° and 35°C. The temperature coefficients of conductance (1/Λ)(ΔΛ/Δt) for the intervals 5–25° and 25–45°C increase linearly and in parallel with FD corresponding to 8.1 percent and 5.7 percent respectively on passing from H2O to D2O.
A Theory of the Thermodynamic Properties of Large Molecules
Authors: Powell Richard E. , Clark Charles R. , Eyring Henry
Published: January 2005

The nature of the viscosity of linear polymers led Kauzmann and Eyring, in an earlier paper, to interpret flow as occurring by means of the more or less random motion of segments. In this paper it is shown that this theory of motion of segments provides an explanation for a variety of thermodynamic properties. These are: (a) the change of melting temperature with chain length; (b) the abnormally large increase in the osmotic pressure of large linear polymers with concentration; (c) the abnormally large vapor pressure of solvent above concentrated solutions of such polymers; (d) the fact that surface tension becomes independent of the molecular weight for long molecules; (e) the volume and entropy changes of swelling of polymers. The theory for the effect of concentration of solvent is developed and segment lengths are calculated. All effects indicate segments of the order of 20 atoms in length, the length varying with the nature of the polymer. According to the theory each of these properties can be used as a basis of a method for testing the rigidity of the structure of macromolecules.
On Some Points of the Bose-Einstein Condensation
Authors: Goldstein L.
Published: January 2005

The peculiar condensation in phase space of ideal Bose-Einstein gases is discussed when the internal energy states of the atoms or molecules is taken into account and when the gas of atoms without internal structure is placed in an external conservative field of force. The inclusion of the internal energy states decreases while the application of the external field increases the condensation temperature from its value in absence of either of these causes. The transition phenomenon, apart from the preceding change in the condensation temperature, proceeds in the same way as in the case of the free gas atoms without internal structure; in particular, the order of the transition remains invariable, as the continuity of the heat capacity at constant volume is maintained at the transition point.
Vibrations of Long Chain Molecules; Raman Spectra of n-Octane, Decane, Cetane and Eicosane in the Liquid State
Authors: Rosenbaum E. J.
Published: January 2005

The Raman spectra of n-octane, decane, cetane and eicosane in the liquid state have been photographed. With increasing chain length the low-lying Raman lines (< 800 cm—1) become few in number and very diffuse. This observation is interpreted in terms of a number of chain configurations co-existing in the liquid state in contrast to the extended configuration found by x-ray analysis of crystalline paraffins. Theoretical investigations which assume that the carbon atoms in a chain are coplanar are not applicable to data obtained for liquid (and gaseous) paraffins.
On the Anharmonicity of Vibrations of Polyatomic Molecules. I
Authors: Redlich Otto
Published: January 2005

Several simplifying assumptions concerning the vibrational potential energy of polyatomic molecules are discussed and tested by means of the available experimental material. One of these assumptions furnishes relations between the higher coefficients of the potential energy of molecules containing several equivalent bonds. If a molecule contains p equivalent bonds XY, the potential energy of the corresponding symmetric stretching vibration, and only of this one, can be approximated by means of a Morse function with the constants pD and a/ √p in the place of D and a. The anharmonicity factors of bending vibrations are small if the third-order coefficient of the potential energy vanishes on account of the symmetry of the molecule.
Infra-Red and Raman Spectra of Polyatomic Molecules XIV. Propylene
Authors: Wilson E. Bright , Wells A. J.
Published: January 2005

The infra-red spectrum of gaseous propylene has been studied from 3 to 25μ with a spectrometer using fluorite, rocksalt and KBr prisms. A normal coordinate calculation of the fundamental frequencies has been made, using force constants obtained principally from ethylene and ethane. This information, when combined with the known Raman spectrum, permits an assignment of fifteen of the twenty fundamental frequencies and puts limits on four of the remaining frequencies.
Anomalous Dispersion and Dielectric Loss in Polar Polymers
Authors: Kirkwood John G. , Fuoss Raymond M.
Published: January 2005

A theory of dielectric loss of polar polymers at high dilution in a nonpolar plasticizer is developed. The theory leads to a broad distribution in relaxation times, associated with the internal rotatory Brownian motion of the hydrocarbon chain. An approximate relation between the degree of polymerization, the frequency of maximum loss, and the viscosity coefficient of a polar plastic is obtained. The loss factor is calculated from the theoretical relaxation time distribution for a mono-disperse polymer and for a poly-disperse polymer with an exponential distribution in chain length. The theoretical loss factor is compared with the experimental loss factor of polyvinyl chloride plasticized with diphenyl. The agreement with experiment is semi-quantitative.
Thermal Diffusion in Ternary Liquid Mixtures, Particularly Aqueous Solutions Containing Ferrous Chloride
Authors: Gillespie L. J. , Breck Samuel
Published: January 2005

The accumulative arrangement of Clusius and Dickel for thermal diffusion was used to study the concentration changes at the extreme ends of the apparatus that occur in various mixtures, particularly solutions of two solutes in water. The apparatus gave reasonably reproducible results. To avoid uncertainties due to creeping along the upper part of the hot wall, any apparatus intended for the study of slightly soluble substances should be designed, as was the apparatus used, so that it can be filled without leaving an air space between hot and cold wall. The enrichment of acetic acid in water solution at the cold (and lower) end is rather small, compared with that of glycerine, or many salts or strong acids. Addition of sodium acetate does not greatly affect the enrichment of acetic acid. The enrichment of ferrous chloride in water at the cold end is considerable, but in the presence of 1M HCl the enrichment occurs at the hot end. In the presence of 1N H2SO4 the enrichment was zero. The case is opposite with zinc chloride. Here the small cold-end enrichment that occurs in the presence of a trace of acid to prevent hydrolysis is considerably increased in the presence of 1M HCl. In a solution of ferric chloride and 1M HCl the enrichment of iron was also at the hot end. Hydrolysis takes place, but this probably works against such a result. It appears that a heavy constituent of a ternary liquid solution can migrate from cold to hot end, against the direction normally expected. A simple function of the composition is given whose sign is the same as the sign of the enrichment at the cold end in all binary mixtures (liquid or gaseous) so far studied, but not always the same in ternary mixtures.
A Partition Function for Normal Liquids
Authors: Walter John , Eyring Henry
Published: January 2005

A theory of liquids designed to account for rate as well as thermodynamic properties is given. By considering the molecules of the liquid to be distributed at random among solid-like and gas-like equilibrium positions, where the introduction of a new equilibrium position requires a volume increase of about ⅛ the molecular volume, it is possible to derive an explicit partition function for liquids. The model embodies the features previously used in the theory of viscosity and diffusion. The thermodynamic properties of argon, nitrogen and benzene are calculated and compared with experiment.
Second Virial Coefficients of Polar Gases
Authors: Stockmayer W. H.
Published: January 2005

An equation is given for the classical second virial coefficient of a polar gas in terms of the parameters appearing in an intermolecular potential energy which includes London and dipole attraction and inverse-power repulsion. The equation is successfully fitted to the data for H2O and NH3 with allowance for the small quantum correction, and the derived values of the London constant are in good accord with theoretical estimates. The defects of the model and its relation to the concept of the hydrogen bond are briefly discussed.
Theory of Acid Strength. Temperature Effect
Authors: Magee John L. , Ri Taikei , Eyring Henry
Published: January 2005

Thermodynamic treatment shows that for chemical reactions whose equilibrium constants go through maxima (or minima) the relationship ln K−ln Km=p(T−θ)2+q(T−θ)3+···holds in the neighborhood of Tm=τ. Km is the extreme value of K. The constants p and q are equal to p=(ΔCp)θ2Rθ2;  q=−{(2/3)(ΔCp)θ−(1/6)(∂ΔCp∂T)θ1Rθ3.Equation (a), aside from the cubic and higher terms, has been proposed by Harned and Embree to apply to the experimental data on acidic dissociation. It is shown that for acidic dissociation in aqueous solution the properties of water almost completely determine the values of p and q. Estimates of these constants are made. The mechanism of the dissociation process is discussed, and it is shown that the equation for the dissociation of water can be represented by (m+n+2)H2O⇌H3+O(nH2O)+OH−(mH2O),where m+n+2≅16. This is in accord with the result of Harned and Fallon for mixtures of water and dioxane log10p0/p=12.2N2,in which p is the ion product for the mixture which contains a mole fraction N2 of dioxane; and p0 is the ion product for pure water.
Reduction of Magnesium Oxide by Tungsten in Vacuum
Authors: Moore George E.
Published: January 2005

A method for calculating rates for a class of chemical reactions in vacuum is developed and applied to the reaction in which tungsten reduces magnesia to give free magnesium. The calculations were tested experimentally and the observed and computed values were found to be in substantial agreement.
Atomic Distributions in Liquid Elements
Authors: Gamertsfelder Carl
Published: January 2005

Monochromatic x-ray diffraction patterns of liquid chlorine, tin, indium, zinc, cadmium, aluminum, and lithium were obtained, using Mo Kα radiation. The effect of temperature change on the patterns was determined for tin and indium. Fourier analyses of these patterns led to the determination of atomic distribution curves for each element. Each atom in liquid chlorine has one nearest neighbor, which means that chlorine is diatomic in the liquid state. The distribution curves for liquid tin, zinc and aluminum agree very well with the distributions in the corresponding crystals. The distribution curves for indium, cadmium, and lithium do not agree very well with distributions in the corresponding crystals.
Note on Diamagnetic Anisotropy and the Method of Molecular Orbitals
Authors: Brooks Harvey
Published: January 2005

The simple London theory of the diamagnetic anisotropy of organic molecules containing benzene rings is modified to include the effect of a non-orthogonality of 25 percent between atomic wave functions on adjacent atoms. Except in the case of diphenyl the effect of such a modification is surprisingly small; that is, although the contributions to the anisotropy from individual electronic orbits is materially changed the resultant contribution of all the electrons is hardly altered. The significance of this result is discussed.
On Some Properties of Bose-Einstein Gases
Authors: Goldstein Louis
Published: January 2005

The condition which has to be fulfilled in order that the Bose-Einstein condensation be accompanied by a discontinuity of the heat capacity at the condensation temperature is discussed. The nature of the transition depends on the distribution of the energy levels of the individual particles forming the gas. The condensation is studied for several types of individual energy spectra. It is shown that all those Bose-Einstein (B.E.) assemblies which admit a non-ambiguous definition of the statistical distribution function present, beside interesting analogies, a qualitatively different behavior from that observed in liquid helium. It appears that as long as the transition in momentum space of non-ideal B.E. systems is not understood, the possibility of connection between B.E. condensation and the transition observed in liquid helium remains an open problem.
The Infra-Red Absorption Spectrum of Propane
Authors: Wu Violet L. , Barker E. F.
Published: January 2005

Of the twenty-seven internal degrees of freedom of propane, all nondegenerate, twenty-two may appear as fundamental absorption bands. These bands fall into three symmetry classes, designated A1, B1 and B2, and distinguishable by their characteristic contours. Because of overlapping, however, it is impossible in many cases to determine their positions precisely. This is especially true in the regions of the C–H valence and deformation frequencies. Some ten or twelve fundamental bands may be identified with confidence as well as a number of combinations. An A1 band at 870 cm—1 and a B2 band at 748 cm—1 have been partially resolved, the line spacing being about 1.47 cm—1 in agreement with predictions based upon electron diffraction measurements. The fine structure of the B1 bands has not been observed (the predicted spacing is 0.5 cm—1) but the interval between maxima of the P and R branches is approximately 26 cm—1 as expected. With 24 cm-atmospheres of gas no bands were observed between 15μ and 35μ, although the symmetrical C–C deformation might be expected to produce a band of appreciable intensity within these limits. This frequency has apparently been observed in Raman spectra at 375 cm—1.
The Structure of Black Carbon
Authors: White Addison H. , Germer Lester H.
Published: January 2005

This paper is concerned with the structure of extremely small crystallites of carbon deposited upon silica by the pyrolysis of methane. Electron diffraction patterns have been obtained from more than 100 carbon films, from some by the reflection method, and from others by transmission after removing the films from their supports with hydrofluoric acid. In some of the specimens the individual crystallites are strongly oriented and reflection patterns obtained from these are approximations to rotation patterns from single crystals. From these patterns we have concluded that the films are made up of pseudo-crystals in each of which the carbon atoms are hexagonally arranged in planes as they are in graphite, but successive parallel atomic layers are displaced so that no regularities exist other than the uniform separation of the planes and the regular arrangement of atoms in each of them.
Statistical Mechanics of Fusion
Authors: Kirkwood John G. , Monroe Elizabeth
Published: January 2005

A statistical mechanical theory of fusion based upon the use of local free energies is presented. An integral equation is formulated for the distribution function of average density in a region occupied by a system of molecules. Periodic solutions characteristic of a crystalline phase are found for certain ranges of values of a set of parameters depending upon temperature and volume. When the parameters decrease below certain critical values, all terms of the Fourier series representing the distribution function vanish with the exception of the constant term. A uniform density distribution characteristic of a fluid phase is then obtained. The melting parameters of argon at several pressures are calculated with the aid of the theory and compared with experiment.
The Heat Capacity of Certain Halomethanes
Authors: Glockler George , Edgell Walter F.
Published: January 2005

A semi-empirical method of calculating the heat capacities of the halomethanes is presented. It is based on additive contributions of the bonds and angles making up the molecule. Values obtained for eighteen molecules at three temperatures by this method are compared with those calculated by statistical means. The average deviation is 0.9 percent.
Evidence for a Rigid Multilayer at a Solid-Liquid Interface
Authors: Eversole W. G. , Lahr Paul H.
Published: January 2005

The assumption of an immobile hydrous multilayer at a wall of fixed potential was used in deriving equations relating zeta potentials, concentrations of univalent salt solution, wall potential, and thickness of the immobile layer. Calculations were made using data taken from published papers of various experimenters. Values of 8A to 63A were obtained for the thickness of the immobile layer. The values of wall potential and film thickness were considered sufficiently consistent for each set of data to justify the original assumption.
Deviations from Ohm's Law in Soda Lime Glass
Authors: Maurer R. J.
Published: January 2005

The conductivity of soda lime glass has been measured as a function of field strength between 0°C and 110°C. The data are compared with a recent theory of electrolytic conductivity of solids. The form of the deviation from Ohm's law is correctly represented by this theory up to field strengths of 7×105 volts/cm. Reasonable values for the physical constants result from the measurements.
The Reaction Between Hydrogen and Oxygen: Kinetics of the Third Explosion Limit
Authors: Heiple Harold R. , Lewis Bernard
Published: January 2005

The third explosion limit of hydrogen and oxygen has been investigated in spherical Pyrex vessels of different sizes, covered with an almost invisible layer of KCl, at temperatures from 530° to 570°C, using different ratios of hydrogen and oxygen, and inert gases, nitrogen, helium, and argon. The results are described rather well by the mechanism developed by Lewis and von Elbe from experiments at the second explosion limit and the reaction above it. The explosion is preceded by an induction period, which decreases to zero at higher pressures. It is shown that such third limit explosion pressures of zero induction period are representative of the isothermal branched chain explosion, whereas lower third limit explosion pressures with induction periods have a thermal disturbance superimposed, the difference between the two values providing a measure of the magnitude of the thermal effect. From the energy of activation of k2 for reaction H+O2=OH+O determined at the second explosion limit, and the slope of the third explosion limit curve with temperature determined by Oldenberg and Sommers in a heavily KCl-coated vessel for zero induction period, an energy of activation of k10 for reaction the HO2+H2=H2O2+H was calculated to be 33.5 kcal. This agrees with the value 32.9 kcal. found by calculating k10 directly from the experimental data. This sets an upper limiting value of the bond energy of H and O2 in HO2 as 65.3 kcal. The energy of H and HO2 in H2O2 then has a lower limiting value of 69.5 kcal. It is pointed out that the third explosion limit per se does not lend itself well to a study of the reaction mechanism. This must be provided by studies of the second explosion limit and the reaction above it which are in progress. The third explosion limit can, however, provide support for any mechanism so developed.
High Frequency Energy Losses in Solutions Containing Macromolecules
Authors: Conner Willard P.
Published: January 2005

There is described a quantitative thermal method for measuring the loss factor of solutions containing polar molecules. By making use of the Debye dipole theory for both parts of the complex dielectric constant, it is found that normal lignin is fairly homogeneous and has a molecular weight of approximately 3900 and a shape factor of 8. The ω-hydroxydecanoic acid polymers show internal rotation of the polar groups in solution, whereas methyl methacrylate linear polymers appear to have less, but still appreciable, internal group motions.
The Photolysis of Acetone in Presence of Mercury
Authors: Saunders Kenneth W. , Taylor H. Austin
Published: January 2005

The photolysis of acetone in the region 2600–2900A has been studied at temperatures from 100–275°C, alone, in presence of liquid mercury, mercury vapor and mercury dimethyl. From a comparison of the products formed in each case and the effect of temperature thereon a mechanism is suggested which indicates that mercury methyl, if not mercury dimethyl, is formed by reaction between methyl radicals and mercury atoms suggesting a greater stability of the mercury methyl radical than hitherto believed.
Statistical Mechanics of Imperfect Gases
Authors: Montroll Elliott W. , Mayer Joseph E.
Published: January 2005

The application of statistical mechanical equations to the calculation of thermodynamic properties of imperfect gases has been hindered by the occurrence of highly multiple integrals in these equations. By observing that some of these multiple integrals are related to the iterated kernels of an integral equation involving the potential energy function of a pair of molecules, a technique is developed which expresses these integrals in terms of the characteristic values of the integral equation. This technique is applied to the calculation of third virial coefficients and the molecular distribution function (which is essentially the probability of finding two specified molecules in two small volume elements a distance r from each other) at various temperatures for imperfect gases with Lennard-Jones potential energy functions.
The X-Ray Diffraction Pattern of Tricalcium Aluminate
Authors: Brady Lynn J. , Davey Wheeler P.
Published: January 2005

Using a new type of x-ray diffraction apparatus, the diffraction pattern of high purity tricalcium aluminate, (3CaO·Al2O3), has been recorded automatically in the form of a graph of intensity vs. angle. The unit cube containing 264 atoms has an edge of 15.235A.
The Magnetic Susceptibility of Ti and Zr
Authors: Squire C. F. , Kaufmann A. R.
Published: January 2005

The paramagnetic susceptibilities of Ti and Zr have been found to increase linearly with increasing temperature from 20°K until a crystal structure change occurs at high temperatures. Electrical conductivity, specific heat, and thermal expansion studies were made on Zr and the evidence indicates a change in the electron configuration.
The Thickness of the Rigid Water Film at a Quartz-Water Interface from a Measurement of Newton's Rings
Authors: Eversole W. G. , Lahr Paul H.
Published: January 2005

The thickness of the water film between a quartz lens and disk was determined by measuring the radii of successive Newton's rings. The squares of these radii are a linear function of the order of the rings from the center, the intercept of the extrapolated graph of which is a function only of the radius of curvature of the lens and the vertical separation of the lens and plate. By comparing intercepts obtained from data taken before and after evaporation of a water layer, a value of the order of 100A was obtained for the thickness of the water film of each interface.
Optical optimization of polyfluorene-fullerene blend photodiodes
Authors: Persson Nils-Krister , Arwin Hans , Inganas Olle
Published: January 2005

Blends of polyfluorene-fullerenes are promising materials for polymer-based photovoltaic devices (PPVD). Using spectroscopic ellipsometry we deduce the dielectric function for the blend of the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and the alternating polyfluorene copolymer, poly [2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] DiO-PFDTBT (4:1 by weight), for the wavelength interval 250–1300nm. n reaches above 2 and saturates to 1.9 for high wavelengths. Absorption starts at 720nm (1.72eV) and reaches a crest around 550nm (2.25eV). The spin coating introduces anisotropy in the blend, manifested in birefringence as well as in dichroism. The dielectric function for the blend versus its constituents is not additive. There are indications that the constituents lost their dielectric identity, as screening cannot explain the experimental data. Simulations of optical absorption inside a PPVD are performed for both monochromatic and polychromatic light, using an air mass 1.5 distributed solar irradiation. The model allows calculation of absorbed energies in absolute values in all layers within the device. An optimization is carried out with respect to the layer thicknesses. From a purely optical perspective there is no gain of optical absorbance in including an additional layer of acceptor. Spatially resolved energy dissipation within the device is presented for polychromatic light. Estimates for quantum efficiencies are derived. Experimental and theoretical results for reflectance are compared.
X-ray photoelectron spectroscopy study of magnetic tunnel junctions
Authors: Lee Hyeon-Jun , Jeong Se-Young , Cho Chae Ryong , Lee J. H. , Joo S. J. , Shin K. H. , Lee B. C. , Kim Tae-Suk , Park J.-H. , Kang J.-S. , Rhie K.
Published: January 2005

Magnetic tunnel junction (MTJ) structures were investigated by x-ray photoelectron spectroscopy. The Al layer was overoxidized and the samples were treated by rapid thermal annealing. It was found that the Mn atoms in the exchange-bias layer diffused into the magnetic layer, but did not reach the oxide barrier. Although slightly higher oxygen concentration was observed at the interface between the magnetic layer and the oxide barrier, strong evidence of the oxidized magnetic-layer interface was not found. Our result is consistent with the high tunneling magnetoresistance of MTJs at room temperature.
Excitation photocapacitance study of EL2 in n-GaAs prepared by annealing under different arsenic vapor pressures
Authors: Oyama Yutaka , Nishizawa Jun-ichi
Published: January 2005

The excitation photocapacitance method was applied to n-GaAs:Te (n=4×1016cm−3) prepared by annealing under various excess arsenic vapor pressures. By changing the primary excitation photon energies, the emission spectra for the EL20→EL2+ and EL2+→EL2++ transitions were determined. Considering the electron capture processes of the valence band (VB)→EL2+ (0.67eV) and VB→EL2++ (0.47eV) at 77K, the Frank–Condon shifts (dFC) of the annealed GaAs crystals were determined for the EL2+ level on the basis of the configuration coordinate model. It was shown that the lattice relaxation around the EL2 level is larger under arsenic-poor conditions, and thus it is considered that arsenic vacancies are closely related with the atomic configuration of the EL2 defect, in combination with excess arsenic defects.
Automated and versatile SQUID magnetometer for the measurement of materials properties at millikelvin temperatures
Authors: Morello A. , Angenent W. G. J. , Frossati G. , de Jongh L. J.
Published: January 2005

We present the design and construction of a SQUID-based magnetometer for operation down to temperatures T≃10mK, while retaining the compatibility with the sample holders typically used in commercial SQUID magnetometers. The system is based on a dc-SQUID coupled to a second-order gradiometer. The sample is placed inside the plastic mixing chamber of a dilution refrigerator and is thermalized directly by the He3 flow. To measure the magnetic moment, the sample is moved through the gradiometer coils by lifting the whole dilution refrigerator insert. A home-developed software provides full automation and an easy user interface.