bluuebunny/crossref_metadata_2025 huggingface dataset:
The Kinetics of the Chromic Acid Oxidation of Isopropyl Alcohol: The Induced Oxidation of Manganous Ion
Authors: Watanabe Warren , Westheimer F. H.
Published: January 2005

1. Isopropyl alcohol ``induces'' the chromic acid oxidation of manganous salts to MnO2. The limiting induction factor (ratio of moles of MnO2 to moles of acetone formed) is one-half.

2. In the presence of manganous ion the rate at which chromic acid is reduced by isopropyl alcohol is decreased; the maximum decrease in rate observed under a wide variety of experimental conditions is 50 percent.

3. These facts, together with the previously determined reaction kinetics, demand the formation of an intermediate chromium compound in which chromium has the valence four or five.

4. Within chemically reasonable limits, all the reaction mechanisms involving such transitory intermediates have been examined. In the presence of manganous salts the only possible mechanism is HCrO4−+CH3CHOHCH3→Cr4+CH3COCH3,Cr4+Mn++→Cr++++Mn+++,2Mn++++2H2O→Mn+++MnO2+4H+.In the absence of manganous salts several mechanisms (all of which are listed) are possible.
Rate of Nucleation in Condensed Systems
Authors: Turnbull D. , Fisher J. C.
Published: January 2005

On the basis of the nucleation theory developed by Volmer, Becker, and co-workers, and the theory of absolute reaction rates, an expression is derived for the absolute rate of nucleation in condensed systems.
Raman Spectra of Polycrystalline Hydrocarbons at Low Temperatures. Rotational Isomerism. II
Authors: Rank D. H. , Sheppard N. , Szasz G. J.
Published: January 2005

Making use of the low pressure, water-cooled Hg arcs as the source of nearly monochromatic radiation, a simple method was developed for the investigation of the Raman spectra of polycrystalline solids. The method was applied to the study of the first four normal paraffins. The Raman spectra of the solids between 600–1500 cm−1 are compared with those in the liquid phase. All these spectra undergo a marked simplification on solidification due to the disappearance of all but one of the rotational isomers. This process is shown to be discontinuous at the melting point.
Spectroscopic Studies of Rotational Isomerism. III. The Normal Paraffins in the Liquid and Solid States
Authors: Sheppard N. , Szasz G. J.
Published: January 2005

The Raman spectra of n-butane, n-pentane, n-hexane, and n-heptane have been investigated in the liquid phase between 310°K and their melting points, and also in the solid phase. The room temperature spectra clearly show the presence of appreciable concentrations of two rotational isomers in butane and pentane, and of three isomers in hexane and probably in heptane. In the solid phase only one of these isomers is present, and in agreement with previous conclusions based on spectroscopic and other evidence, this lowest energy form was assumed to possess the planar, trans-, zig-zag configuration. The spectra of the solids yield experimental values for the limiting skeletal stretching frequencies of the zig-zag form, and these were compared with values calculated by previously established methods. The photoelectric spectrograph was used for quantitative intensity measurements on selected line pairs of each molecule over appropriate temperature intervals, and from the results values were obtained for the energy difference, —ΔH, between rotational isomers. The values obtained were 760±100 cal. mole−1 in n-butane, 450±60 cal. mole−1 in n-pentane, 520±70 and 470±60 cal. mole−1 in n-hexane. No quantitative result could be obtained for n-heptane. The observed gaseous heat capacities of n-butane, n-pentane, and n-hexane were compared with values calculated by statistical mechanics. It was found that for n-pentane and n-hexane the calculated values do not agree accurately with the experimental results, probably because of the simplified partition functions used to obtain the compositions of the isomeric mixtures.
The Normal Vibrations of Polyatomic Molecules as Calculated by Urey-Bradley Field. III. A Table of Force Constants
Authors: Simanouti Takehiko
Published: January 2005

Assuming the Urey-Bradley field for various chemical structures, stretching, bending and repulsive force constants were determined so as to give the best fit with the observed vibration frequencies. The magnitude of these force constants, especially of repulsive constants, was discussed.
The Kinetics of Membrane Processes. I. The Mechanism and the Kinetic Laws for Diffusion through Membranes
Authors: Laidler K. J. , Shuler K. E.
Published: January 2005

The equations for diffusion in binary systems are extended to the case of diffusion through a membrane. Three elementary rate processes are considered at a solution-membrane interface: (1) adsorption of the diffusing species, (2) desorption back into the solution, and (3) diffusion into the membrane, and an expression for the rate constant of the over-all process of surface penetration is developed in terms of three specific rate constants. Various special cases are considered and discussed with reference to the experimental data. A general expression for the rate of diffusion of a species through a membrane under steady-state conditions is derived, the rate being expressed as a function of activities. It is shown that the application of this expression to the case of a solvent passing through a membrane which is impermeable to the solute leads to the thermodynamically exact equation for the osmotic pressure. Expressions are given for the rate of flow of solvent and solute through a membrane as a function of the osmotic and hydrostatic pressures across the membrane.
The Kinetics of Membrane Processes. II. Theoretical Pressure-Time Relationships for Permeable Membranes
Authors: Laidler K. J. , Shuler K. E.
Published: January 2005

The rate equations developed in Part I for the flow of solvent and solute through a permeable membrane have been extended to the case in which the flow is measured by the rise and fall in a capillary inserted into the more concentrated solution. The differential equation obtained for this case has been integrated to give an explicit relationship between the height of rise in the capillary and the time. The equation is shown to give the height-time relationship in the form found by experiment. It is shown that the osmotic pressure obtained with a semipermeable membrane is a special case of the more general theory of diffusion through membranes permeable to both solvent and solute. The possibility of positive and negative values of P, i.e., of initial rise or fall respectively in the capillary, is discussed, and the significance of these cases evaluated in terms of the molar volumes and permeation constants of solvent and solute.
The Kinetics of Membrane Processes. III. The Diffusion of Various Non-Electrolytes through Collodion Membranes
Authors: Shuler K. E. , Dames C. A. , Laidler K. J.
Published: January 2005

Measurements have been made of the rates of diffusion of various non-electrolytes, and of water, through a collodion membrane separating a dilute solution from pure water. The determinations were made by measuring the rate of rise and fall in a capillary tube in the solution, and analyzing the results using the procedure described in a previous paper. The work was done with 0.25N solutions of sucrose, lactose, raffinose and mannitol, and was carried out at different temperatures so that energies and entropies of activation could be determined. The energy of activation for diffusion through the membranes was found in all cases to be slightly less than for free diffusion, a result that is shown to be consistent with a positive heat of adsorption of the solute and solvent at the membrane. Analogously the entropies of activation for membrane diffusion are somewhat less than for free diffusion, since the process of adsorption brings about a decrease in entropy. The rate of diffusion of water through a membrane is shown to depend upon the nature of the solute diffusing, a result which arises from the fact that diffusion is a mutual process. An experiment is described in which there is an initial net flow from the solution into the solvent.
Internal Rotation IV. The Optical Activity and Isomerization Energy of the Rotational Isomers of D-Secondary Butyl Alcohol
Authors: Bernstein H. J. , Pedersen E. Egelund
Published: January 2005

The specific rotation of secondary butyl alcohol was measured in dilute solutions of cyclohexane at intervals of 5° between 20°C and 70°C inclusive.

After corrections for solvent effect and change of refractive index with temperature had been made there remained a definite temperature dependence of the rotivity.

Interpretation of the results on the basis of three optically active rotational isomers (two of equal energy and the third less stable) gave the rotivity of the third isomer as −21° and the sum of the other two as +21°.

The heat of isomerization was found to be 803 cal. per mole.

The concentrations of the three rotational isomers at 20° are calculated as 42.3 percent, 42.3 percent, and 15.3 percent.
Changes in the Crystal Structure of AgBr When Exposed to X-Rays
Authors: Brentano J. C. M. , Spencer L. V. C.
Published: January 2005

Controversial evidence has appeared in the literature concerning the constancy of the lattice parameter of AgBr with varying exposure to radiation. This paper gives in detail experiments showing that the lattice parameter does not change appreciably with increasing exposure to x-rays.
Application of a General Theory of the Formation of Liquid Films to Solutions of Lanthanum Chloride
Authors: Robinson Lawrence Baylor
Published: January 2005

A general theory of the formation of liquid films is applied to the case of lanthanum chloride. The hyperelliptic integrals involved are approximated with elliptic integrals. The small values of the zeta-potentials make reliable assignments of the values of the ``corrected surface tensions'' difficult.
The Calculation of Ionic Resonance Energies
Authors: Pearson Ralph G.
Published: January 2005

A molecular orbital calculation is made of the bond energy between dissimilar atoms, A—B. The principle of the geometric mean and experimental bond energies between similar atoms are used to evaluate the exchange integral. The other parameter needed is the difference in coulombic energy of an electron on atom A and on atom B. This is related to the difference in Pauling's empirical electronegativity values. Numerical results are given for non-polar bonds and the best polar bonds and comparison is made with experimental bond energies.
The Energy of Dissociation H2O→H+OH
Authors: Oldenberg O.
Published: January 2005

The various lines of evidence regarding the energy of dissociation H2O→H+OH are critically discussed. This gives a basis for discussing the energy of activation of the process OH+OH→H2+O2.
Role of Hydrogen Peroxide in the Thermal Combination of Hydrogen and Oxygen
Authors: Holt R. B. , Oldenberg O.
Published: January 2005

Hydrogen peroxide was identified as an intermediate product in the steady thermal combination of hydrogen and oxygen near 540°C by an examination of the absorption spectrum of the reacting mixture. The absorption at a particular wave-length (2537A) was then used in a quantitative study of the variation of hydrogen peroxide concentration in the reacting mixture as a function of conditions. The results obtained were compared with those obtained by chemical analysis of the gas mixture. The commonly accepted mechanism of the reaction proposed by Lewis and von Elbe is applied to the interpretation of the results obtained.
The Born-Mayer Model for Ionic Solids and the Heats of Formation and Lattice Spacings of Alkali Halide Solid Solutions
Authors: Wallace W. E.
Published: January 2005

Previous attempts to calculate the heats accompanying formation of alkali halide solid solutions from the component salts have met with only limited success. The difficulties may have originated either in the use of Vegard's law to obtain lattice spacings of the solutions or in the general inadequacy of the model employed in computing the energies of the lattices concerned. Since earlier studies were based on the old Born concept of ionic solids, it was of interest to examine the subject again using as a basis the more refined treatment due to Born and Mayer. An expression for the potential energy of a crystalline solution has been developed in terms of the known interaction parameters of the pure constituents and has been used to compute the equilibrium spacings and heats of formation of three chosen systems. The calculated results are compared with experiment. The comparison suggests that further refinement in the model is perhaps necessary before the small changes in lattice spacings and heat contents which accompany solid solution formation can be completely accounted for.
A Theory of Vapor Pressures of Liquids Based on van der Waals' Equation of State. II. Binary Mixtures
Authors: Wall Frederick T. , Stent Gunther S.
Published: January 2005

An expression for vapor pressures of binary liquid systems obeying van der Waals' equation of state is developed by generalizing a recent theory of vapor pressures of pure liquids. The resulting partial vapor pressure equations involve composition and temperature, and contain no empirical quantities other than van der Waals' constants including an inter-species interaction term.

The conditions under which Raoult's law holds for these systems are formulated, together with the conditions for which positive or negative deviations occur. The compositions at which azeotropes form are predicted, and the partial miscibility of binary liquid systems is discussed. A number of examples are calculated to illustrate the theory.
Diffusion in Photo-Chemical Experiments: The Photo-Chemical Decomposition of Acetone
Authors: Hill Terrell L.
Published: January 2005

A theoretical analysis is made of the effects of diffusion on the reactions following the photo-chemical decomposition of acetone in a cylindrical cell. It is found that some of the results are quite sensitive to the fate of the free radicals on the walls of the cell. The root-mean-square distance a radical diffuses in its mean lifetime is shown to be a useful qualitative guide in predicting the importance of diffusion in experiments of this type.
Dielectric Behavior of Solutions of Electrolytes in Solvents of Low Dielectric Constant. V. The Influence of Temperature and Concentration on Dielectric Properties
Authors: Strobel H. A. , Cole R. H.
Published: January 2005

Dielectric loss and conductance data for octadecyltributylammonium thiocyanate in benzene show large changes in the significant frequency region of absorption and in the magnitude of conductance when the temperature is lowered from 25° to 6°C, but their variation with concentration is very similar at the two temperatures. The broad frequency range of absorption observed at concentrations in the range 0.008–0.02 molal and the failure of the change in macroscopic viscosity to account for the temperature effect suggest that a better understanding of similar systems requires more detailed examination of the interaction of the ionic and dipolar aggregates with the solvent.
Dipole Moment and Restricted Rotation in Some Chlorinated Hydrocarbons
Authors: Oriani Richard A. , Smyth Charles P.
Published: January 2005

Measurements of the variation of gas phase dipole moment with temperature of six chlorinated hydrocarbons are described. 1,2-dichloropropane, and, to a very small extent, 2,3-dichloropropene and 1,1,2-trichloroethane display a dependence of dipole moment on temperature. 1,4-dichlorobutane and the two isomers of 1,3-dichloropropene have dipole moments constant over the temperature range investigated. The results are analyzed both by adopting simple parametric functions to represent the potential hindering intramolecular rotation, and by computations of intramolecular energies.
Reduced Temperatures for the Liquid State. General Equations for the Orthobaric Densities as Functions of the Reduced Temperature
Authors: Scott Arthur F. , Dillon Robert
Published: January 2005

The reduced temperature θ proposed by Bauer, Magat, and Surdin for the liquid state is presented and their work is reviewed. Attention is directed to the fact that a number of empirical power law equations that represent the variation of a property of a liquid as a function of the van der Waals reduced temperature are directly transformable into analogous functions of θ. General equations are derived for the variation of the orthobaric liquid and vapor densities as function of the reduced temperature.
A Quantum-Mechanical Theory of Light Absorption of Organic Dyes and Similar Compounds
Authors: Kuhn Hans
Published: January 2005

The most important organic compounds which absorb visible light can be classified into three groups typified: (a) by symmetrical polymethines, (b) by porphyrines, (c) by polyenes.

Recently it was shown that the position of the absorption maxima of symmetrical polymethines and related compounds (symmetrical cyanine and oxanole dyes; Michler's hydrol blue and derivatives; malachite green and other triphenyl methane dyes; etc.) can be calculated by adopting a model of the dye molecule which is analogous to the free-electron gas model used in particular by Sommerfeld to describe the condition of metals. The π-electrons of the polymethine chain are considered as a one-dimensional free-electron gas which extends itself along the length of the chain.

In the normal state the stablest energy states of the electron gas each contain two electrons in accordance with Pauli's exclusion principle. The remaining states are empty. The existence of the first absorption band is a consequence of the jump of a π-electron from the highest energy level occupied in the normal state to the lowest empty level.

For the wave-length of the maximum of the first absorption band of this group of dyes, the relationship obtains that λ1=(8mc/h)(L2/[N+1]),where L is the length of the polymethine zig-zag chain, N, the number of π-electrons, m, the mass of the electron, c, the velocity of light, h, Planck's universal constant. Good agreement with experimental results for λ1 is obtained by the use of this equation.

The problem of porphyrine and phthalocyanine compounds can also be dealt with on the basis of a free-electron gas model. We treat the π-electrons of the porphyrine ring as electrons which are confined to move in a closed ring-shaped path in a field of constant potential energy.

In the case of polyenes and related compounds (Carotenes, unsymmetrical cyanines and oxanoles, merocyanines, azo- and stilbene dyes, etc.) a description by means of a free-electron gas model is no longer permissible. The electron gas in this case suffers a disturbance from its condition in the case of the first and second groups of dyes, and, to allow for this, the π-electrons are considered placed in a one-dimensional potential having a sine curve periodicity. The wave-length λ1 is expressed by λ1=[V0hc(1−1N)+h8mcN+1L2]−1,where V0 is the amplitude of the sine-shaped potential along the chain.

This relation is confirmed by the experimental data. It also gives an explanation for the markedly different manner (compared with the symmetrical polymethines) in which the position of the absorption bands of polyenes and related compounds depends on the chain length.

The results of the classical color theory of Witt are capable of a simple explanation when considered in the light of the electron gas model.
Complete Sets and Redundancies among Small Vibrational Coordinates
Authors: Decius J. C.
Published: January 2005

A simple prescription is given for defining internal coordinates of the bond stretching, bending, out-of-plane bending, and torsional types which yields a kinematically complete set of vibrational coordinates with no redundancies in acyclic molecules and with 6μ redundancies in cyclic molecules, where μ is the number of bonds which must be deleted to render the molecule acyclic.
The Ionization of Polymeric Electrolytes
Authors: Wall Frederick T. , deButts Edward H.
Published: January 2005

A theory is developed for the ionization of polymeric acids and bases. Using the theory it is possible to calculate the pH and equivalent conductances of aqueous polymeric electrolyte solutions as functions of concentration. A general formula is derived for ionization constants of acids and bases of any basicity. A graphical comparison of calculated and measured equivalent conductances confirms the essential features of the theory. It is also shown indirectly that the conductance of a polymeric acid is due almost entirely to the hydrogen ions.
Hindered Rotation in Ethyl Alcohol
Authors: Halford J. O.
Published: January 2005

Previous evaluations of the barriers hindering the internal rotations in ethyl alcohol are shown to be unsatisfactory because they fail to produce agreement between molecular and calorimetric entropies over a wide enough temperature range. The principal source of difficulty is found in an inconsistency between the modified Berthelot equation of state and the calorimetric data and vapor pressures used in calculating the third law entropies. Corrections for gas imperfection should be much higher at the temperatures at which the barrier evaluations have been made, but these corrections cannot be determined accurately with the available data. The larger entropies permit the assignment of lower and more reasonable potential barriers.

For the hydroxyl group rotation, to keep the heat capacity, and therefore the change of entropy with the temperature, within the indicated limits, the simple expression V = V0(1—cos3θ)/2 is more suitable than more detailed potential energy functions. With a reasonable assignment of the vibrational frequencies, the sum of the barriers restricting the hydroxyl and methyl group rotations is approximately 6000 cal.
The Exchange Reaction between Bromine and Bromotrichloromethane
Authors: Miller A. A. , Willard J. E.
Published: January 2005

Thermal exchange of the bromine in CCl3Br with Br2 has been measured in the temperature range from 100° to 135°C in liquid CCl3Br, in the range from 135° to 170°C in CCl4 solution, and in the range from 150° to 220°C in the gas phase. The activation energy has been found to be approximately 29 kcal. mole−1 in each phase. The rate of exchange has been found to be proportional to the first power of the CCl3Br concentration and to the square root of the bromine concentration, indicating an atomic mechanism. The values of the rate constants obtained in the liquid and gas phases are approximately equal. From the results it may be deduced that the activation energy for the step which initiates the exchange, i.e., either CCl3Br+Br→CCl3+Br2 or the reaction CCl3Br+Br*→CCl3Br*+Br is about7 kcal. mole−1. This value is in the range of values of 5–10 kcal. mole−1 indicated by previous experiments on the analogous photochemical reaction in carbon tetrachloride solution. The thermal reaction has been found to be much less sensitive to oxygen than various previously studied photo-chemical halogenation reactions. Analysis of the results suggests that the ``cage'' effect may appreciably lower the quantum yield of the photo-chemical reaction in the liquid phase.
The Kinetics of the Vapor Phase Exchange of Radioactive Bromine between Trichlorobromomethane and Bromine
Authors: Davidson Norman , Sullivan John H.
Published: January 2005

The rate of exchange of radioactive bromine between trichlorobromomethane and bromine in the vapor phase in the temperature range 420−455°K has been determined. The rate is equal to k[Br2]½[CCl3Br], where log10k(moles/liter)−12(sec.)−1=(−33,100(±400))/(4.574T)+12.75(±0.20). The energy of activation for the elementary reaction between bromine atoms and trichlorobromomethane molecules is 10.3 kcal., and the frequency factor is 7.9×1010. It is proposed that the reaction proceeds via the sequence: Br*+BrCCl3→BrBr*+—CCl3, and Cl3C—+Br2*→Cl3CBr*+Br*, rather than by a Walden inversion mechanism. The observation that chloroform is formed when hydrogen bromide, bromine, and trichlorobromomethane are heated is cited as evidence for the presence of —CCl3 radicals and for the reaction Cl3C—+HBr→Cl3CH+Br. The —CCl3 radical is then more stable than the —CH3 radical by 10 kcal. or more.

The vapor pressures of liquid trichlorobromomethane are given by the equation: log10p(mm)=(−8240/4.574T)+7.64. The exchange reaction Br2(g)+AgBr*→Br2*(g)+AgBr readily goes to completion and is the basis for a convenient semi-micro method for the preparation of radioactive elementary bromine.
Bipyramidal Pentacovalent Bond Orbitals
Authors: Duffey George H.
Published: January 2005

The Pauling-Slater theory of directed valence is applied to the trigonal bipyramid structure. Covalent molecules of the type AB5 are considered. It is assumed that the bonding orbitals are of composition sp1+2nd3–2n, and the bond strengths are determined as a function of n.
Concerning the Work of Polarization in Ionic Crystals of the NaCl Type. II. Polarization around Two Adjacent Charges in the Rigid Lattice
Authors: Hutner R. A. , Rittner E. S. , Pré F. K. du
Published: January 2005

The method of the Mott-Littleton first-order approximation for the polarization work is extended to the case of the removal of two adjacent charges from a rigid lattice of the NaCl type. Numerical results are given for NaCl and RbCl.
Internal Rotation III The Potential Barrier in 1, 2-Dichloroethane
Authors: Bernstein H. J.
Published: January 2005

The potential energy as a function of azimuthal angle has been computed on the basis of an inverse fifth power of the distance law for the energy of interaction. Suitable corrections for second order interactions were also made. A three minima potential curve is obtained of the form V=0.733(1−cosφ)+1.123(1−cos3φ)+0.197(1−cosφ)(1−cos3φ) K cal./mole.The barrier is computed to be 2.81 K cal./mole.
The Thermodynamics of High Polymer Solutions. V. Phase Equilibria in the Ternary System: Polymer 1—Polymer 2—Solvent
Authors: Scott Robert L.
Published: January 2005

A thermodynamic analysis of phase equilibria similar to that developed in Part IV when applied to the ternary system of two polymers and a solvent leads to an explanation of the usual incompatibility of different high polymers in solution. Unless their heat of mixing is virtually zero or negative, two high polymers are always immiscible in the absence of a solvent; the primary role of the solvent is non-specific, merely one of diluting the polymer mixture and decreasing the heat of interaction of the polymers. The recent experiments of Dobry and Boyer-Kawenoki show reasonable agreement with these theoretical conclusions. Osmotic pressures of mixed polymers are discussed; such measurements would permit determination of μ12, the interaction constant of the two polymers.
The Kinetics of the Thermal Decomposition of Propylene
Authors: Szwarc M.
Published: January 2005

The thermal decomposition of propylene was investigated for temperatures ranging from 680°C up to 870°C and with percentages of decomposition from 0.01 percent up to about 2 percent. The reaction was shown to be a homogenous gas reaction of the first order, the first-order constant being given by an expression 1.1·1013 exp—(72,000/RT). Two mechanisms are discussed, both of which account for the observed kinetics and products of decomposition. It is demonstrated that the first step in the thermal decomposition of propylene is the splitting of the C–H bond leading to the formation of H atoms and allyl radicals. The problem of the value of D(C–H) in propylene is discussed in the light of the two suggested mechanisms. An attempt is made to account for the variety of the reactions between H atoms and propylene molecules as observed by various investigators.
The Kinetics of the Thermal Decomposition of Isobutene
Authors: Szwarc M.
Published: January 2005

The thermal decomposition of isobutene was found to be a homogeneous gas reaction of the first order. The first-order constant is 0.5·1013 exp(67,000/RT). The products of the decomposition included H2, CH4, and allene. The experimental results are explained in terms of a chain mechanism, the initiating step being the decomposition of the isobutene molecule into an H atom and a [Complex chemical formula] radical. The most probable value of the D(C–H) in isobutene is 76 kcal./mole. This estimate is based on certain assumptions concerning the frequency factors.
Vibrational Analysis of the 3400A Triplet-Singlet Emission of Benzene
Authors: Shull Harrison
Published: January 2005

The triplet-singlet emission of benzene at 3400A in a rigid glass-solution has been obtained and measured more accurately than in previous work. An assignment is proposed accounting for all the important bands observed. The analysis of the vibrational structure indicates the presence of the 703 cm−1 b2g fundamental, showing that in the triplet-singlet transition, the triplet level combines in the same manner as a 1B1u state for electric dipole radiation. This will lead to a definite assignment of the symmetry of this triplet level when the theoretical rules for intercombinations in polyatomic molecules are derived. The analysis supports a hexagonally symmetric planar model for this triplet state.
Theory of the Thermal Diffusion of Electrolytes in a Clusius Column
Authors: Guthrie George , Wilson J. Norton , Schomaker Verner
Published: January 2005

A theory is presented which accounts approximately for the apparently anomalous difference between the thermal diffusion coefficients of an ion in the presence and in the absence of other electrolytes; the theory is based on the existence of an electric field parallel to the thermal gradient in the electrolyte as a consequence of the variation in mobility among the various ions present. It is pointed out also that some data on the behavior of electrolytes in a Clusius column are at variance with the Debye exponential law concerning the steady-state distribution of solute.
Burning Velocities of Butadiene−1,3 with Nitrogen-Oxygen and Helium-Oxygen Mixtures
Authors: Badin Elmer J. , Stuart Joseph G. , Pease Robert N.
Published: January 2005

Burning velocities of nitrogen-oxygen-butadiene−1,3 and helium-oxygen-butadiene−1,3 have been measured at atmospheric and reduced pressures. At atmospheric pressure the ratio of 3.7:1 for the maximum burning velocities was obtained for helium compared to nitrogen as the inert gas. Reduction of pressure caused an increase then a decrease in burning velocity for helium-oxygen-butadiene−1,3. The maximum value of the burning velocity occurred at 300 mm pressure. Calculations of the equilibrium concentrations of H, O, and OH for the gas mixtures used have been made. Assuming that the controlling factor in the burning velocity is the back-diffusion of H-atoms, good agreement between calculated and experimental burning velocity ratios is obtained.
The Effect of Droplet Size on Surface Tension
Authors: Tolman Richard C.
Published: January 2005

The effect of droplet size on surface tension is given theoretical consideration with the help of results of the Gibbs thermodynamic theory of capillarity and of previous results of the author as to the sign and magnitude of superficial densities. It is concluded that surface tension can be expected to decrease with decrease in droplet size over a wide range of circumstances. In addition, approximate figures are obtained for the rate at which such decreases may be expected. The decreases become significant for very small drops. The results are of interest in view of the important role of surface tension in determining the behavior of small droplets.
Temperature Variation of Ultrasonic Velocity in Liquids
Authors: Lagemann R. T. , McMillan D. R. , Woolf W. E.
Published: January 2005

Measurements have been made of the ultrasonic velocity in thirty-four organic liquids over a temperature range of 0−60°C by use of a variable-path ultrasonic interferometer operating at 500,000 cycles per second. For all of the liquids studied the relation between velocity and temperature was found to be essentially linear. Values of density, adiabatic compressibility, and temperature coefficient (ΔV/ΔT) are also reported. It was found that the successive substitution of a heavier atom in a molecule leads to successively smaller temperature coefficients. It is pointed out that the temperature coefficient of ultrasonic velocity appears to be inversely proportional to the square root of the molecular weight, to a fair degree of accuracy.
Simple Potential Functions and the Hydrogen Halide Molecules
Authors: Davies Mansel
Published: January 2005

Five simple molecular potential functions have been tested by comparison with spectroscopic data for the hydrogen halides. It is shown that when plotted on a ``reduced'' distance scale (r/re), the potential curves for these molecules coincide closely up to Δ(r) = 0.10re. Two electrostatic functions indicate β/rn as the more satisfactory form of the repulsive term. Significant values of the effective polarizability and ``fractional ionic character'' are deduced. The latter are higher and more nearly constant than the uncorrected values currently quoted as showing changing bond type in these molecules. The results conform with Kirkwood's very successful treatment of HCl as a polarizable ion pair.

Of purely empirical functions, the Pöschl-Teller provides a slight improvement upon the simple Morse relation, and is only a little more cumbersome than the latter. The Rosen-Morse function is less satisfactory for these molecules. Simple expressions are given for evaluating the three parameters in these functions from spectroscopic data.
An Experimental and Theoretical Investigation of the Skeletal Frequencies of the Paraffin Hydrocarbons and the Far Infra-Red Spectrum of Carbon Tetrachloride
Authors: Gates David M.
Published: January 2005

The far infra-red spectra of the paraffin hydrocarbons and of carbon tetrachloride have been investigated. The following bands were located: propane at 370.6 cm−1, n-butane at 215 cm−1, and carbon tetrachloride at 315 cm−1, the latter showing isotope structure. The contours of the following near infra-red bands for n-butane were surveyed, and some fine structure was revealed: 1342.9 cm−1, 1295.6 cm−1, 1135.6 cm−1, 956.5 cm−1, and 740.0 cm−1. The assignment of the skeletal frequencies of vibration is made, and a theoretical analysis of the skeletal normal frequencies, assuming a valence potential for the molecules propane through pentane, is given.
Contribution of the Deviation from Perfect Gas Behavior to the Entropy and Heat Capacity. Water and Benzene
Authors: Halford J. O.
Published: January 2005

The properties of water vapor are used to illustrate the point, previously found true for ethyl alcohol, that the modified Berthelot equation of state may not give a satisfactory evaluation of the deviation of thermodynamic properties from those of the hypothetical perfect gas. The entropy deviation for benzene, however, is accurate enough for most purposes, and the heat capacity is not too far out of line.

On limited information, it appears that the Berthelot equation may be satisfactory for the vapors of ``normal'' liquids up to limited pressures. It is recommended, however, that some attempt be made to check the properties by means of vapor densities, obtained directly or by the Clapeyron equation, before results based upon the Berthelot equation are accepted.
The Application of Ultrasonics to the Study of Electrolytic Solutions III. The Effect of Acoustical Waves on the Hydrogen Electrode
Authors: Yeager Ernest , Hovorka Frank
Published: January 2005

An equation is developed for the alternating component in the electrode potential of a hydrogen electrode exposed to acoustical radiations. According to these calculations, the effect is of the magnitude 10−2 volt for acoustical waves with a pressure amplitude of 0.1 atmos. The hydrogen electrode should prove very useful as a means for absolute measurements of pressure amplitude as well as the detection of underwater sound.
Neutron Absorption Cross Sections of Radioactive La140 and Two Stable Cerium Isotopes
Authors: Katcoff S. , Leary J. A. , Walsh K. A. , Elmer R. A. , Goldsmith S. S. , Hall L. D. , Newbury E. G. , Povelites J. J. , Waddell J. S.
Published: January 2005

Two multi-curie samples of 40-hr. La140 were irradiated with slow neutrons at the Los Alamos homogeneous pile for 24 hours. The small amount of 3.7-hr. La141 formed was allowed to decay to 28-day Ce141 which was then radio-chemically extracted and counted. From the activity measured, the neutron flux, and the known half-lives, a value of 3.1±1.0 barns was calculated for the cross section of 40-hr. La140. The thermal neutron absorption cross sections of stable Ce140 and Ce142 were also measured and found to be 0.27±0.06 and 0.105±0.020 barn, respectively, per atom of the naturally occurring element.
The Interpretation of the Vibrational Spectra of the C6 Hydrocarbons 22-Dimethyl Butane, 22-Dimethyl−3-Butene, and 22-Dimethyl−3-Butyne
Authors: Sheppard N.
Published: January 2005

Assignments have been made for the observed infra-red and Raman frequencies of the molecules 22-dimethyl butane, 22-dimethyl−3-butene, and 22-dimethyl−3-butyne. By using the previously assigned characteristic frequency regions associated with the ethyl, vinyl, and C≡CH groups, it has been shown that the tertiary butyl group in all these molecules has frequencies near 1250, 1210(2), 1025(2), 880, and 700 cm−1, in the range 1350–600 cm−1. The assignment of these frequencies to skeletal C–C stretching and to methyl wagging modes is discussed.
Spectral Resemblances of Cata-Condensed Hydrocarbons
Authors: Klevens H. B. , Platt J. R.
Published: January 2005

The spectra of naphthalene, anthracene, naphthacene, phenanthrene, 1,2-benzanthrene, chrysene, and acenaphthene in n-heptane solution are extended to 1700A. Electronic energy levels of 17 such cata-condensed hydrocarbons are collected and compared. The lowest five or six excited states shift in a regular way with changes of molecular length and shape. Intensities and vibrational structures of corresponding bands are remarkably alike in the different compounds. The total oscillator strength is almost proportional to the number of π-electrons, but the proportionality constant differs from that in polyenes. With new identifications, the positions of energy levels in naphthalene, anthracene, and azulene agree remarkably well with previous LCAO molecular orbital calculations.

The lowest singlet state is of one type in benzene, naphthalene, and most non-linear systems; of another type in anthracene and the higher linear polyacenes because of a cross-over. This clears up some controversial questions, such as the relations among the spectra of naphthalene, anthracene, and phenanthrene.
Classification of Spectra of Cata-Condensed Hydrocarbons
Authors: Platt John R.
Published: January 2005

The classification of π-orbitals in a cata-condensed aromatic system is like that of the orbitals of a free electron traveling in a one-dimensional loop of constant potential around the perimeter. To take into account electron interaction, certain quantities corresponding to angular momenta may be added or subtracted. Introduction of the cross-links in the molecule removes the degeneracy. The first excited configuration in such systems gives two low frequency singlet weak absorption bands and two higher singlet strong dipole absorption bands. Selection and polarization rules are given. The levels are identified from the spectra and some of their properties are determined. An explanation is given of the regularities found by Klevens and Platt. A systematic nomenclature is given. The results agree qualitatively with LCAO theory, can be applied easily to unsymmetrical molecules, and can possibly be extended to other types of ring systems.
On the Mechanism of Viscosity of Liquids
Authors: Telang M. S.
Published: January 2005

A new viscosity-temperature relationship for liquids has been derived, and its application has been studied. The derivation is based upon the theory of viscosity by Eyring et al., rectifying the ``activation energy'' term. The ``activation energy'' term has been shown to be equivalent to the free energy of formation of a surface and the error committed by previous workers regarding the evaluation of ``activation energy'' has been discussed. The proposed equation is free from any arbitrary or empirical terms, and since, in particular, it does not involve any quantities derived from viscosity measurements, it makes a direct calculation of viscosity possible.
The Absorption Spectra of Transuranic Salts in Crystals
Authors: Freed Simon , Leitz Fred J.
Published: January 2005

Absorption spectra, mainly in the visible and near ultraviolet regions, were taken of the following anhydrous salts at room temperature and at that of liquid nitrogen: uranium tetrachloride, neptunium tetrachloride, plutonium trichloride, americium trichloride (and americium tribromide).

The spectra of these salts have the features characteristic of rare earth spectra, sharp lines clustered in groups. It follows that the heavy elements have their least stable electrons within the inner 5f shell when their ions are in activated as well as in their basic electronic states.

The spectra of the salts of americium are among the sharpest known from crystals—even at room temperature. In this respect they are matched, as far as we know, only by the salts of trivalent europium ion. The spectra confirm the resemblance drawn between these ions on other grounds and make it very likely that trivalent americium has six electrons in the 5f shell with 7F0 for its basic electronic state.

The experimental method requires at most several micrograms of the salt for obtaining spectra of considerable dispersion.
Calculation of the Energy of Vaporization of Perfluorocyclopentane from Intermolecular Forces
Authors: Rohrback Gilson H.
Published: January 2005

By assuming a probable representative orientation of perfluorocyclopentane molecules in the liquid state, the energy of vaporization has been calculated, using both the London-Margenau equation of dispersion forces and the Slater-Kirkwood formula. Using only the data from density and dispersion measurements, fair agreement was found to the value experimentally determined. It is seen on the basis of this calculation that the contribution of the dipole-quadrupole interaction to the London formula is important.
Vibration Spectra of Cis and Trans C2H2Cl2 and C2D2Cl2
Authors: Bernstein H. J. , Ramsay D. A.
Published: January 2005

The infra-red spectra of gaseous and liquid cis and trans C2H2Cl2 and C2D2Cl2 have been obtained in the region 3500 to 400 cm−1.

The fine structure of a ⊥ band in trans C2H2Cl2 was also resolved and the least moment of inertia obtained.

An assignment of all the fundamentals for the four molecules has been made.

Calculations of potential functions and of the equilibrium constants for the reaction cis⇌trans support the assignment.
The Photo-Chlorination of Methyl Chloroformate in Carbon Tetrachloride Solution
Authors: Batke T. L. , Dorfman L. M. , LeRoy D. J.
Published: January 2005

A study has been made of the kinetics and photo-chemistry of the chlorination of methyl chloroformate to monochloromethyl chloroformate in carbon tetrachloride solution at 25°C. The reaction is strongly inhibited by oxygen. The following mechanism has been proposed for the reaction in the absence of oxygen:[Complex chemical formula]
Thermodynamic Properties of Diiodoacetylene and Some Symmetrical-Top Acetylenes
Authors: Ziomek Joseph S. , Cleveland Forrest F.
Published: January 2005

In this paper tables are presented of the thermodynamic functions—heat content, free energy, entropy, and heat capacity—of diiodoacetylene, methylchloroacetylene, methylbromoacetylene, methyliodoacetylene, methylacetylene, and methyldeuteroacetylene, for several temperatures from their boiling points up to 1000°K, for the ideal gaseous state at one atmosphere pressure. These functions were calculated from the Raman spectral data for all of the substances except methyldeuteroacetylene, for which the frequencies used were those calculated with force constants transferred from methylacetylene.
A Geometric Approach to the Theory of the Carbon-Carbon Bond
Authors: Zimmerman Howard K.
Published: January 2005

A geometric method of constructing the carbon-to-carbon bonds is described. It is postulated that there exists a region of high, constant electron density between the bound atoms. Calculations based on this postulate confirm it in that they lead to screening constants which are in fair agreement with the values given by Pauling and that plots of the variation of electron density with changes in the angular or radial variables reflect just such a region. Further, the plots are in good qualitative agreement with the well-known properties of rotation about a single bond and lack of rotation about a double bond.
The Fermi Gas Model Applied to the Thermal Electromotive Forces of Tin, Lead, and Indium
Authors: Pimentel George C. , Sheline Raymond K.
Published: January 2005

The absolute thermoelectric powers of tin, lead, and indium in the temperature range of 2−10°K are taken from data of Keesom and Matthijs. The temperature dependence of thermal e.m.f. is parabolic, as predicted for a Fermi gas. With an additional assumption regarding a mean free path parameter (i.e., d(logl)/dε≪1), the Fermi energies for tin, lead, and indium are calculated to be 5.72, 2.89, and 1.20 ev, respectively. Low temperature specific heat data then provide an estimate of the number of conduction electrons per atom. The latter values are 2.54, 2.39, and 0.50, respectively.
Dielectric Relaxation of Molecules Containing Rotating Polar Groups
Authors: Budó A.
Published: January 2005

Debye's theory of dielectric relaxation has been extended to molecules consisting of two similar polar groups, which cannot rotate freely relatively to one another owing to their mutual potential energy. As a result, the mean dipole moment of the molecule in the field F0 exp(iωt) can be expressed by a sum of terms of Debye's type, namely Cλ/(1+iωτλ), where the relaxation times τλ and the constants Cλ are determined by an eigenvalue problem. τλ and Cλ are calculated in the case of the cosine coupling between the groups and in the case of the quasi-elastic bond. The results are compared with the experimental data for chloro-derivatives of diphenyl.
The Heats of Combustion of Polythene and Polyisobutylene
Authors: Parks George S. , Mosley John R.
Published: January 2005

Values, with uncertainties of about 0.03 percent, are here presented for the heats of combustion of polythene and polyisobutylene. The results for polythene indicate that this polymer is crystalline at least to the extent of about 50 percent at 25°C. The results for polyisobutylene are abnormally high and can be explained on the basis of a steric interference effect within the molecules of this liquid polymer.
Vibrational Spectrum and Infra-red Polarization Measurements for Malononitrile
Authors: Halverson Frederick , Francel Rudolph J.
Published: January 2005

The infra-red spectra of gaseous, liquid, and solid malononitrile have been obtained using a spectrometer equipped with LiF, NaCl, and KBr prisms. Polarization measurements on a linearly oriented preparation of solid malononitrile using a transmission polarizer were of material assistance in the classification of absorption bands into their respective species. These data, together with the Raman data in the literature and a normal coordinate treatment, permitted a complete assignment of the fifteen fundamental frequencies and a determination of the force constants and thermodynamic functions for the molecule.