Fully differential cross sections for electron-impact excitation-ionization of alignedD2

Abstract

We examine fully differential cross sections for 176 eV electron-impact dissociative excitation-ionization of orientated D 2 for transitions to final ion states 2sσ g , 2pσ u , and 2pπ u . In previous work [Phys. Rev. A 88, 062705 (2013)], we calculated these cross sections using the molecular four-body distorted wave (M4DW) method with the ground-state D 2 wave function being approximated by a product of two Dyson 1s-type orbitals. The theoretical results were compared with experimental measurements for five different orientations of the target molecule (four in the scattering plane and one perpendicular to the scattering plane). For the unresolved 2sσ g + 2pπ u final states, good agreement with experiment was found for two of the five measured orientations, and for the 2pσ u final state, good agreement was found for three of the five orientations. However, theory was a factor of 200 smaller than experiment for the 2pσ u state. In this paper, we investigate the importance of the approximation for the molecular ground-state wave function by repeating the M4DW calculation using a better variational wave function for the ground state.

Experimental and theoretical study of electron-impact ionization plus excitation of aligned H2

“…In conclusion, we present a comparison between experiment and theory for the 4-body QDCS problem of electron-impact ionization of molecular H 2 with simultaneous excitation of the final state ion. Similar measurements have been recently reported by Lower et al [14,15]. However, in that work the cross sections were integrated over a 40°angular range for the ejected electron and a 10°angular range for the scattered electron to achieve acceptable statistics.…”

“…The experimental results were compared with the results of the M4DW calculation and reasonably good agreement with experiment was found-much better than was found for the much smaller data set [14,15] and very much better than was found for the equivalent atomic scattering problem of electron-impact excitation-ionization of helium [10,11]. Two different ground state wavefunctions were used in the calculation and a significant wavefunction dependence was found.…”

“…The details of the M4DW approach were presented in [14] and [15] so only a brief overview will be presented here.…”

“…An experiment of this type was recently performed in Canberra, Australia [13][14][15]. In that experiment, the energy resolution was good enough to resolve the σ 2p u state but not the individual σ 2s g and π 2p u states.…”

Ionization-excitation of helium by high-resolution(e,2e)spectroscopy and 4-body distorted-wave calculations

“…In contrast to the profound theoretical knowledge based on very precise experimental data that has been achieved for the static structure of atoms and molecules, our knowledge for the dynamic problem is rather limited [1], even for a very simple system, such as the dynamics of the electronimpact ionization. Recently, the experimental techniques and theoretical methods have improved greatly for treating the ionization problem [2][3][4][5][6][7][8][9][10][11][12]. The helium atom, the simplest many-electron system with correlation effects that need to be taken into account, has been extensively explored as the target of electron-impact ionization .…”