Measurement of differential M-shell X-ray emission cross-sections for bismuth

Measurement of differential M-shell X-ray emission cross-sections for bismuth at different angles has been reported. The present results confirm the prediction of the calculations of Flugge et al. [S. Flugge, W. Mehlhron, V. Schmidt, Phys. Rev. Lett. 29 (1972) 7] that the atomic inner-shell vacancies produced after photoionization are aligned and the X-ray emission from the filling of these vacancy states with j > 1/2 are anisotropic. These results contradict the predictions of Cooper and Zare [J. Cooper, R.N. Zare, Atomic Collision Processes, vol. xic, Gordon & Breach, New York, 1969, p. 317] that, after photoionization of inner shells, the vacancy states have equal population of magnetic substates and the subsequent X-ray emission is isotropic.