Collisions of He in Doubly Excited States with Ar: Correlation Effects in Collision Dynamics

Naoto Koyama；Atsuko Takafuji；Michio Matsuzawa

Chinese Journal of Physics

27卷4期（1989 / 08 / 01）

323 - 334

英文

To understand the collisional properties of atoms in doubly excited states, we have theoretically investigated the excitation processes of doubly excited He atoms by collisions with Ar, paying particular attention to the correlated motion of the two excited electrons. The doubly excited states of He are described in hyperspherical coordinates and in terms of the super-multiplet classification scheme based on the rovibrator model of the' collective motion of XYX triatomic molecules. We employ the impulse approximation to describe collision processes. We have neglected the He++Ar interaction and made use of experimental data on e-Ar elastic scattering cross-sections to describe the e-Ar interaction. Evaluating the cross-sections from some initial states to various final states, we have found some systematic trends, i.e. ”propensity rules”, in the excitation processes between the doubly excited states. A set of simple propensity rules is presented for the excitation processes from the 1S^e to the 1S^e and 1p^o doubly excited states of He and interpreted based on the rovibrator model. The results are briefly compared with those previously obtained for electron impact excitation processes.