dc.creator Claydon, Charles R. en_US dc.date.accessioned 2006-06-15T13:32:02Z dc.date.available 2006-06-15T13:32:02Z dc.date.issued 1972 en_US dc.identifier 1972-K-4 en_US dc.identifier.uri http://hdl.handle.net/1811/9038 dc.description $^{1}$ T. E. Sharp and J. T. Dowell, J. Chem. Phys. 46, 1530 (1967). $^{2}$ F. H. Dorman, J. Chem. Phys. 44, 3856 (1966). $^{3}$ L. G. Christophorou, M. N. Pisanias, and J. G. Carter, Bulletin Am. Phys. Soc. 16, 1347 (1971)."" en_US dc.description Author Institution: Battelle Memorial Institute en_US dc.description.abstract Potential energy surfaces have been calculated for the lowest resonant states of $CH_{4}^{-}$. These calculations are used to correlate the dissociative electron attachment (DA) $spectra^{1,2}$ and the threshold electron excitation spectrum (TEES) of $methane.^{3}$ The peak at 2.5 eV in the TEES spectrum is assigned to the ${\tilde{X}}^{2}A_{1} CH_{4}^{-}$ compound state which is bound with respect to the lowest dissociation limits: $CH_{2}^{-} ({\tilde{A}}^{2}A_{1}) + H_{2} (X^{1}{\Sigma}_{g}^{+})$ and $CH_{3}^{-} (\tilde{X}^{1} A_{1}) + H(^{2}S)$. Thus, this resonance state can decay only by autoionization. This assignment is consistent with no $CH_{3}^{-}$ being formed by dissociative electron attachment to $CH_{4}$ (the lowest excited states of $CH_{3}^{-}$ are not energetically accessible). The $H^{-}/CH_{4}$ peak at 9.0 eV and the $CH_{2}^{-}/CH_{4}$ peak at 10.4 eV of the DA $spectrum^{1}$ are assigned to the ${\tilde{A}} ^{2}T_{2} CH_{4}^{-}$ compound state. It is proposed that the inverse isotope $effect^{1}$ for H production $[{\sigma}(H^{-}/CH_{4}) {\approx} 0.8 {\sigma} (D^{-}/CD_{4})]$ and the large direct isotope effect for $CH_{2}^{-}$ production $[{\sigma}(CH_{2}^{-}/CH_{4}) > 260 {\sigma} (CD_{2}/CD_{4})]$ may be the result of the Jahn-Teller splitting of the triple degeneracy of the $\tilde{A}^{2}T_{2}$ resonance state. en_US dc.format.extent 159139 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title THEORETICAL INTERPRETATION OF THE ELECTRON SCATTRING SPECTRUM OF METHANE en_US dc.type article en_US
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