Abstract
The angular asymmetry parameter beta for 5s photoionisation in xenon has been measured in the energy range where the relativistic random-phase approximation (RRPA) including 5s, 5p and 4d interchannel couplings predicts a strong deviation from the nonrelativistic value of two. The authors' data clearly show a deviation from the value two but not as pronounced as predicted by the RRPA calculation. This indicates that the theory has to be further improved in this case.