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1 Dec 1946

Volume 14, Issue 12, pp. 701-743


Mass Spectrometric Study of CH3D. Dissociation Probabilities of C☒H and C☒D Bonds by Electron Impact

Marjorie W. Evans, Norman Bauer, and J. Y. Beach

J. Chem. Phys. 14, 701 (1946); http://dx.doi.org/10.1063/1.1724089 (7 pages) | Cited 12 times

Online Publication Date: 22 December 2004

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A pure sample of CH3D has been prepared and studied in the mass spectrometer. The mass spectrum of CH3D cannot be predicted from that of CH4 by assuming complete similarity between H and D (except mass). More information has been obtained on the difference in behavior of H and D on electron impact previously noticed by Delfosse and Hipple for C2H2D2. There is a difference in dissociation probability of C☒H and C☒D bonds which is approximately constant for several ionization processes and over a considerable range in electron energy. In addition to this there is a difference in behavior of H atoms in CH4 and H atoms in CH3D. In order to account for the mass spectrum of CH3D in terms of the mass spectrum of CH4 both these effects must be taken into consideration. Re‐examination of the data of Delfosse and Hipple points not only to the difference between H and D atoms in C2H2D2, but also to a difference in behavior of H atoms in C2H4 and H atoms in C2H2D2.

The Mercury Photo‐Sensitized Reaction Between Hydrogen and Oxygen

David H. Volman

J. Chem. Phys. 14, 707 (1946); http://dx.doi.org/10.1063/1.1724090 (7 pages) | Cited 10 times

Online Publication Date: 22 December 2004

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The mercury sensitized reaction between hydrogen and oxygen in a flowing system was studied. The quantum yield of the reaction was found to be less than unity, and no evidence of a chain reaction at 40° was found. Hydrogen peroxide was the principal product, and yields of peroxide above 90 percent were found for many of the experiments. It was shown that in the gas phase reaction between ozone and hydrogen peroxide, water was rapidly formed. The yield of product was found to increase with increasing oxygen flow rate, with increasing total flow rate for a fixed hydrogen to oxygen ratio, and to increase and then decrease with increasing hydrogen to oxygen ratio. The reaction scheme proposed is
math
This leads to the rate equation,
math
using the flow rates of hydrogen and oxygen. k1/k2 is the ratio of quenching efficiencies of hydrogen and oxygen for activated mercury or 1.62. k3/k4″ is taken equal to 1.2×10−3.

Investigation of Oxidation of Copper by Use of Radioactive Cu Tracer

J. Bardeen, W. H. Brattain, and W. Shockley

J. Chem. Phys. 14, 714 (1946); http://dx.doi.org/10.1063/1.1724091 (8 pages) | Cited 49 times

Online Publication Date: 22 December 2004

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A very thin layer of radioactive copper was electrolytically deposited on a copper blank. The surface was then oxidized in air at 1000°C for 18 minutes, giving an oxide layer with a thickness of 1.25×10−2 cm. After quenching, successive layers of the oxide were removed chemically, and the copper activity in each layer was measured. The observed self‐diffusion of radioactive copper in the oxide agrees quantitatively with a theory based on the following assumptions: (a) The oxide grows by diffusion of vacant Cu+ sites from the outer surface of the oxide inward to the metal. (b) The concentration of vacant sites as the oxygen‐oxide interface is independent of the oxide thickness, and drops linearly from this constant value to zero at the metal boundary. (c) Accompanying the inward flow of vacant sites, there is a flow of positive electron holes such as to maintain electrical neutrality. (d) Self‐diffusion of copper ions takes place only by motion into vacant sites. The results give a fairly direct confirmation of the theory of oxidation first suggested by Wagner.

A Proposed Interpretation of the Zeta‐Potential

Lawrence B. Robinson

J. Chem. Phys. 14, 721 (1946); http://dx.doi.org/10.1063/1.1724092 (4 pages) | Cited 6 times

Online Publication Date: 22 December 2004

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The method used by Gurney and Fowler in explaining the interfacial potential at a metal‐solution boundary is applied to the zeta‐potential. This gives the ζ‐potential as a straight line function of the logarithm of the concentration, in agreement with the shape of the curves as found experimentally. To obtain exact agreement between theory and experiment, it is proposed that the dielectric constant of the electrical double layer is about 0.6 that of the value for pure water. This assertion can be checked by accurate measurements on the surface conductance of solution of electrolytes.

Absorption of Water by Films of Cellophane and Polyvinyl Alcohol

E. Creutz and Robert R. Wilson

J. Chem. Phys. 14, 725 (1946); http://dx.doi.org/10.1063/1.1724093 (4 pages) | Cited 2 times

Online Publication Date: 22 December 2004

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The absorption of water and dehydration of these films is found to obey a diffusion equation by means of which a diffusivity may be defined. This is not a constant but depends on the water concentration in the foils. A rapid change in water content immediately after changing the ambient conditions suggests the presence of adsorbed surface layers. The total absorption is found to increase faster than the relative humidity.

Thermodynamic Properties of Gaseous Boron Trifluoride, Boron Trichloride, and Boron Tribromide

Hugh M. Spencer

J. Chem. Phys. 14, 729 (1946); http://dx.doi.org/10.1063/1.1724094 (4 pages) | Cited 1 time

Online Publication Date: 22 December 2004

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In this paper are presented tables of the thermodynamic functions heat content, free energy, entropy, and heat capacity of boron trifluoride, boron trichloride, and boron tribromide in the ideal gas state at 1 atmosphere from 298.16° to 1000°K. These functions were calculated from Raman and infra‐red spectra in the case of the two first mentioned and from the Raman spectrum of liquid boron tribromide. A satisfactory calorimetric check of the entropy of boron trifluoride is presented.

The Theory of the Racemization of Optically Active Derivatives of Diphenyl

F. H. Westheimer and Joseph E. Mayer

J. Chem. Phys. 14, 733 (1946); http://dx.doi.org/10.1063/1.1724095 (6 pages) | Cited 39 times

Online Publication Date: 22 December 2004

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T. L. Hill has recently shown that it is possible to compute the magnitude of steric strain in certain organic molecules. The present paper summarizes the results of a similar but independent investigation directed towards a computation of the rate of racemization of optically active (i.e., sterically hindered) derivatives of diphenyl. The energy of the planar form of a sterically hindered diphenyl can be approximated by the equation:
math
where the qi are the normal coordinates of the unstrained molecule in question and the exponential terms are approximations (over the limited range of interest) to the steric repulsions of the non‐bonded groups which repel each other. There are two such exponential terms, for in most sterically hindered diphenyls the repulsion is caused by two pairs of ortho substituents. The equation for E0, the activation energy for racemization, has been found for the symmetrical case by minimizing E; the constants ai, A, and ρ, and the dimensions of the diphenyl derivative appear in the expression for E0. It is also possible to derive equations for the vibration frequencies of the planar form of the sterically hindered molecule (and, therefore, find the entropy of activation); these equations are complicated by the essential degeneracy of the vibrations in question.

On the Equation of State for Gases at Extremely High Pressure

P. Caldirola

J. Chem. Phys. 14, 738 (1946); http://dx.doi.org/10.1063/1.1724096 (4 pages) | Cited 8 times

Online Publication Date: 22 December 2004

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On the basis of the thermo‐hydrodynamic theory of the explosive detonation—developed by Chapman, Jouguet, and R. Becker—a procedure is developed permitting the deduction of the equation of state for gaseous mixtures from explosive processes. The equation is established by starting from several sets of experimental data. In this way one can semi‐empirically derive the equation of state for gases compressed up to 104−105 atmos. The results of numerical calculations are reported.
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The Critical Micelle Concentration of Anionic Soap Mixtures

H. B. Klevens

J. Chem. Phys. 14, 742 (1946); http://dx.doi.org/10.1063/1.1724097 (1 page) | Cited 9 times

Online Publication Date: 22 December 2004

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A Relation Between Bond Multiplicity and Interatomic Distance

R. T. Lagemann

J. Chem. Phys. 14, 743 (1946); http://dx.doi.org/10.1063/1.1724098 (1 page) | Cited 3 times

Online Publication Date: 22 December 2004

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