L3-SUBSHELL VACANCY STATE ALIGNMENT IN PHOTON-ATOM COLLISIONS

The differential cross sections for the emission of Ll, L-alpha-2, L-alpha, L-beta, and L-gamma groups of L x-ray lines induced in Au by 59.57-keV photons have been measured at different angles varying from 40-degrees to 120-degrees at intervals of 10-degrees. The L-alpha-2 line has been isolated by using preferential absorption of the L-alpha line in a Zn absorber of suitable thickness. The L x rays represented by the Ll, L-alpha-2, and L-alpha peaks are found to be anisotropic in the spatial distribution while those in the L-beta and L-gamma peaks are isotropic. The Ll peak has greater anisotrophy than the L-alpha peak. The anistrophy of L-alpha-2 line is opposite to that of L-alpha-1 line. The present results contradict the predictions of Cooper and Zare [Atomic Collision Processes (Gordon and Breach, New York, 1969)], that the vacancy state produced after photoionization is not aligned irrespective of its J value, but confirm those of Flugge, Mehlhorn, and Schmidt [Phys. Rev. Lett. 29, 7 (1972)] that the vacancy state with J > 1/2 is aligned.