Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Physics
Total Dissociative Electron Attachment Cross Sections Of Selected Amino Acids, A.M. Scheer, P. Mozejko, Gordon A. Gallup, Paul Burrow
Total Dissociative Electron Attachment Cross Sections Of Selected Amino Acids, A.M. Scheer, P. Mozejko, Gordon A. Gallup, Paul Burrow
Gordon Gallup Publications
Total dissociative electron attachment cross sections are presented for the amino acids, glycine, alanine, proline, phenylalanine, and tryptophan, at energies below the first ionization energy. Cross section magnitudes were determined by observation of positive ion production and normalization to ionization cross sections calculated using the binary-encounter-Bethe method. The prominent 1.2 eV feature in the cross sections of the amino acids and the closely related HCOOH molecule is widely attributed to the attachment into the –COOH π * orbital. The authors discuss evidence that direct attachment to the lowest σ * orbital may instead be responsible. A close correlation between the …
Resonances And Threshold Effects In Low-Energy Electron Collisions With Methyl Halides, Gordon A. Gallup, Ilya I. Fabrikant
Resonances And Threshold Effects In Low-Energy Electron Collisions With Methyl Halides, Gordon A. Gallup, Ilya I. Fabrikant
Gordon Gallup Publications
Cross sections for elastic and inelastic electron collisions with CH3X(X =Cl,Br, I) molecules are calculated. For the lowest partial wave, the resonance R-matrix theory, and for the higher partial waves, the theory of scattering by dipolar plus polarization potential, are used. It is shown that the rotationally elastic scattering amplitude for a polar molecule in the fixed-nuclei approximation is logarithmically divergent for the forward direction, and a closure formula is derived to speed up the convergence at small angles. In treating the nuclear motion, only C-X stretch vibrations are taken into account. The dipole moment …
Errors In The Application Of The Jwkb Method To Calculating The Survival Factor In Dissociative Electron Attachment Using The Local Complex Potential, Gordon A. Gallup
Errors In The Application Of The Jwkb Method To Calculating The Survival Factor In Dissociative Electron Attachment Using The Local Complex Potential, Gordon A. Gallup
Gordon Gallup Publications
The accuracy of the JWKB method for determining the survival factor defined for dissociative electron attachment (DEA) processes is examined for a range of electronic resonance lifetimes within the local complex potential approximation. The author concludes that the accuracy is inadequate for molecules with properties commonly found for shape resonance induced DEA. More accurate methods using the uniform Airy function approximation give much better results, but the direct numerical integration of Schrödinger’s equation appears simpler still. © 2007 American Institute of Physics.