Effects of autoionization on the photoionization induced alignment of cadmium II (4d9 5s22D/sub 5/2/)

The benchmark process for photoionization-induced alignment in atoms is the fluorescence decay of the excited d hole states of Cd+. Fluorescence polarization measurements, from which alignment is derived, have been made using rare gas lamps and synchrotron radiation at lower resolution. Although evidence had been seen for effects due to the presence of autoionizing resonances, a detailed study of the variation of alignment through an autoionizing resonance had not been made. This thesis reports just such a measurement for the autoionizing 4d95s2(2D/sub 3/2/)np 3P1 and 4d95s2(2D/sub 3/2/)nf 1P1 series in Cd. These Rydberg states, corresponding to the excitation of a single inner-shell electron, form a well-characterized series converging on the 2D/sub 3/2/ fine-structure threshold at 678.3 A. The experiment was performed at the National Synchrotron Light Source (Brookhaven National Laboratory) on beamline U-11. Dispersed synchrotron radiation was crossed with an effusive cadmium beam. Wavelength- and polarization selected fluorescence radiation was detected perpendicular to the two beams. The polarization and alignment data show marked variations on the order of 25% across the resonance profiles, which cannot be reproduced by RRPA-MQDT calculations. This thesis analyzes for the first time the strong effects of bound continuum coupling on the alignment