The ionization dynamics of molecules by electron impact has been studied by  researchers at Atomic Physics Group I at Institute of Modern Physics, Chinese Academy of Sciences (IMP) , in cooperation with colleagues from Max-Planck Institut für Kernphysik (MPIK), Germany and Department of Physics, Missouri S&T University, USA.

Electron impact single ionization of atomic and molecular targets is a fundamental process which is important in a wide range of science and technology, such as plasmas physics, chemistry of planetary atmospheres and radiation damage of living tissues. Detailed information about this process can be obtained from the kinematically complete experiments, or (e, 2e) experiments, which determine the momentum vectors of all continuum particles.

Single ionization of the methane (CH4) 1t2 orbital by 54eV electron impact has been investigated. Triple differential cross sections are obtained under both the coplanar geometry and the no-coplanar geometry, and are compared with the results of the molecular 3-body distorted wave (M3DW) approximation and the distorted wave Born approximation (DWBA). Overall the agreement between experiment and theory was better for the faster electron at smaller scattering angles. The study has confirmed the importance of nuclear scattering by reducing the C-H distance in the theoretical model.

Further, researchers at IMP pointed out that at particular kinematics in the intermediate energy range, the electron momentum distribution of the target molecule plays a major role in the ionization process, rather than the molecular configuration as suggested in previous publications.

The results have been published in Chemical Physics 136, (2012) 237101 and 137, (2012) 024301.

The articles can be linked as follows:

http://jcp.aip.org/resource/1/jcpsa6/v136/i23/p237101_s1

http://jcp.aip.org/resource/1/jcpsa6/v137/i2/p024301_s1

TDCSs for the scattering plane geometry. (Image by IMP)