ROTATIONALLY RESOLVED PHOTOELECTRON-SPECTRA IN RESONANCE ENHANCED MULTIPHOTON IONIZATION OF SIF

Results of calculations of rotationally resolved photoelectron spectra for resonance enhanced multiphoton ionization (REMPI) of SiF via the B2SIGMA+ (4ssigma), C" 2SIGMA+ (4psigma), and C' 2PI (4ppi) Rydberg states are reported. In addition to the expected DELTAN = even peaks, unusually strong DELTAN = +/-1 transitions are predicted for photoionization of the B2SIGMA+ state. These unusual transitions are due to even angular momentum components of the photoelectron matrix element and arise from the formation of Cooper minima in the ionization channels and strong l mixing in the electronic continuum induced by the nonspherical molecular ion potential. Unexpected DELTAN = 0, +/-2 transitions, due to odd wave contributions to the photoelectron matrix element, are also predicted for photoionization of the C" 2SIGMA+ state. Asymmetrical ion distributions with respect to DELTAN = 0 are also predicted for the C' 2PI state. Cooper minima are predicted to occur in the 1 = 2 wave of the kpi photoelectron channel for the B state and in the 1 = 4 wave of the ksigma and kpi channels for the C" state. Photoelectron angular distributions provide further insight into the photoionization dynamics.