Showing papers by "Henry Eyring published in 1936"

Viscosity, Plasticity, and Diffusion as Examples of Absolute Reaction Rates

Abstract: Since to form a hole the size of a molecule in a liquid requires almost the same increase in free energy as to vaporize a molecule, the concentration of vapor above the liquid is a measure of such ``molecular'' holes in the liquid. This provides an explanation of the law of rectilinear diameters of Cailletet and Mathias. The theory of reaction rates yields an equation for absolute viscosity applicable to cases involving activation energies where the usual theory of energy transfer does not apply. This equation reduces to a number of the successful empirical equations under the appropriate limiting conditions. The increase of viscosity with shearing stress is explained. The same theory yields an equation for the diffusion coefficient which when combined with the viscosity and applied to the results of Orr and Butler for the diffusion of heavy into light water gives a satisfactory and suggestive interpretation. The usual theories for diffusion coefficients and absolute electrical conductance should be replaced by those developed here when ion and solvent molecule are of about the same size.

The Theoretical Treatment of Chemical Reactions Produced by Ionization Processes Part I. The Ortho‐Para Hydrogen Conversion by Alpha‐Particles

Abstract: The possible individual processes that may occur in a gaseous system under irradiation from alpha‐particles have been examined from the theoretical standpoint. The ionization, clustering and the fate of the ions have been studied. The ortho‐para hydrogen conversion under the influence of alpha‐particles has been chosen as an example with which to illustrate the method of treatment. Recent experimental data by Capron have been analyzed to confirm his conclusion that atomic hydrogen is responsible for the large ratio of molecules converted to ions produced (M/N = (700 to 1000)/1). It is also shown that clustering is unimportant in this case and that the paramagnetism of the ions is of negligible importance in producing the spin‐isomerization. The role of mercury atoms in removing atomic hydrogen from the system is found to be negligible. Removal of atoms by three body collision of two atoms with molecular hydrogen is slow compared with removal at the walls of the reaction vessel. Analysis of this latter pro...

Reactions Involving Hydrogen Molecules and Atoms

Abstract: The criticisms of Coolidge and James of activation energy calculations are discussed. It is pointed out that their criticisms of the original London proposal do not apply to the semi‐empirical method which in its present form has little more than a formal resemblance to the original scheme. Until a satisfactory quantum‐mechanical derivation of the semi‐empirical method is provided, it must depend for acceptance on its usefulness and the fact that it is a reasonable interpolation formula for calculating the energies of polyatomic molecules from diatomic ones. The best surface for three hydrogen atoms is constructed and from it the rates of all the possible hydrogen‐deuterium reactions are calculated by means of the general theory of absolute rates, these rates are found to be in excellent agreement with the experimental values. The transmission coefficient for reactions on this surface is investigated. Diagrams showing the angular dependence of the potential energy for an H and for a Cl atom approaching a hydrogen molecule are given.

The Radiochemical Synthesis and Decomposition of Hydrogen Bromide

Abstract: A theory is developed for the radiochemical synthesis and decomposition of hydrogen bromide which makes use of experimentally known processes of ionization, the known rates of a few simple chemical reactions, and the extensive experimental results of Lind and Livingston. The analysis indicates that in pure hydrogen gas, six hydrogen atoms are formed per ion pair; in pure hydrogen bromide, six hydrogen bromide molecules would be decomposed; and in equal mixtures of Br2 and HBr the chance that an electron will form negative ions with HBr (HBr +e→H+Br—) is greater than with Br2.