PHOTOFRAGMENTATION ANALYSIS FROM FLUORESCENCE-RADIATION ANGULAR-ASYMMETRY PARAMETER MEASUREMENTS OF AR-4S) FINE-STRUCTURE RESOLVED TRANSITIONS ON RESONANCES((4P)

The angular asymmetry parameter B-fl of the photon-induced fluorescenc e radiation of Ar+(4p-4s) fine-structure resolved satellite lines was measured from threshold up to 38.4 eV. It is well known that the cross sections of these valence shell satellites are dominated by the decay of aligned doubly excited States leading to an extremely complicated energy dependence. In contrast, we observe that the B-fl parameter bec omes less structured with increasing total angular momentum J of the p hotoion. The B-fl measurements can be interpreted by a partial-wave an alysis of the photofragmentation products. For the population of the 4 p(F-2(7/2)) ion state only d5/2 photoelectrons are emitted on all reso nances. For the population of the 4p(D-2(5/2)) and the 4p(P-4(5/2)) io n states the emission of the parity-unfavored d(5/2) photoelectrons do minates.