LIFETIMES OF RYDBERG STATES IN ZERO-ELECTRON-KINETIC-ENERGY EXPERIMENTS .2. ELECTRIC-FIELD-INDUCED AND COLLISIONAL ENHANCEMENT OF XE AUTOIONIZATION LIFETIMES

Lifetime measurements are reported for high principal quantum number (n=43-87) autoionizing Rydberg states of the Xe atom, prepared using state-selective excitation with a narrow bandwidth laser. It is demonstrated that the lifetimes can be increased by l-mixing in dc electric fields, as well as by l,m-mixing through the presence of surrounding Xe+ ions. The influence of l,m-mixing interactions on the peak intensities in zero-electron-kinetic-energy (ZEKE) photoelectron spectroscopy experiments is discussed, and a possible method for increasing the applicability of ZEKE experiments is suggested. In addition, experimental evidence is given for spin-orbit state changing Xe*(n)-Xe collisions. © 1995 American Institute of Physics.