Dynamics of electron impact ionization of the outer and inner valence (1t 2 and 2a 1 ) molecular orbitals of CH 4 at intermediate and large ion recoil momentum
Year: 2009
Type: article
Abstract: The triply differential cross section has been measured for electron-impact ionization of the outer valence 1t 2 and the inner valence 2a 1 orbitals of methane using the (e,2e) technique with coplanar asymmetric kinematics. The measurements are performed at scattered electron energy of 500 eV, ejected electron energy of 12, 37 and 74 eV and for scattering angle of the fast outgoing electron of 6°. This kinematics is characterized by a target ion recoil momentum ranging from moderate (0.25 au) to very large (3.2 au) values. The results are compared with theoretical cross sections calculated using the 1CW and the BBK models recently extended to molecules. The experimental cross sections exhibit a very large recoil scattering, especially for the inner 2a 1 molecular orbital, which is not predicted by the theory. The differences between experiment and theory are attributed to the very strong scattering from the ion, not properly accounted for by theory. This indicates the need for further theoretical developments as well as experimental investigations in order to correctly model the process of molecular ionization.
Language: English
Topic: Atomic and Molecular Physics
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1989437726