Magneto optical trap recoil ion momentum spectroscopy.

摘要

The Magneto Optical Trap Recoil Ion Momentum Spectroscopy (MOTRIMS) technique has been developed for ion-atom collisions experiments. This new approach expands the number of target species available as a target for ion-atom collision. The extreme low temperature of atoms in a magneto optical trap yields increased recoil ion momentum resolution as compared to the traditional COLTRIMS (Cold Target Recoil Ion Momentum Spectroscopy). Furthermore, the traditional method for cooling the target, namely supersonic gas jet expansion, is not suitable for targets with optically active electrons since these species generally form clusters or dimers upon expansion. Because cooling and trapping leaves some atoms with an electron in an excited state, MOTRIMS naturally allows the study of collisions with excited targets. The collision systems presented within this dissertation are for low energy charge transfer between singly charged alkali ions and trapped rubidium atoms. Detailed results from simultaneous measurements of target excited state fraction and kinematically complete relative cross sections for several systems having energetically degenerate channels will be addressed. Furthermore, development of the MOTRIMS technique has enabled it to become an unique probe of population dynamics. This latest development and its implications will be introduced.