Low energy experimental and theoretical triply differential cross sections are presented for electron impact ionization of methane (CH4) for both the highest occupied molecular orbital (HOMO) and next highest occupied molecular orbital (NHOMO). The HOMO is a predominantly p-type orbital which is labeled 1t2 and the NHOMO is predominantly s-type labeled 2a 1. Coplanar symmetric (symmetric both in final state electron energies and observation angles) are presented for final state electron energies ranging from 2.5 to 20 eV. The theoretical M3DW (molecular three-body distorted wave) results are in surprisingly good agreement with experiment for the HOMO state and less satisfactory agreement for the NHOMO state. The molecular NHOMO results are also compared with the ionization of the 2s shell of neon which is the isoelectronic atom.



Keywords and Phrases

Differential cross section; Distorted waves; Distorted-wave theory; Electron energies; Electron impact-ionization; Final state; Highest occupied molecular orbital; Low energies; Observation angle; P-type; Atomic physics; Dissociation; Electron energy levels; Electron-electron interactions; Impact ionization; Methane; Molecular modeling; Molecular orbitals; Experiments

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Article - Journal

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Final Version

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© 2011 American Institute of Physics (AIP), All rights reserved.

Publication Date

01 May 2011

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Physics Commons