APPLICATION OF STEPWISE ELECTRON AND LASER EXCITATION TECHNIQUES TO ELECTRON PHOTON-CORRELATION STUDIES .1. THEORY

A theoretical description is presented for the process in which photons emitted from atoms which have been stepwise excited firstly by electron impact and then by resonant interaction with coherent radiation are detected in coincidence with the inelastically scattered electrons. The optical excitation is modelled using a full quantum electrodynamic theory. Calculations of the Stokes parameters are performed for the Hg (I=0) scheme; electron excitation from the 61S0ground state to the 61P1state followed by resonant laser excitation to the 61D2state, with analysis being performed on the fluorescence from the 61D2-63P1relaxation channel. It is found that for this case, even though manifestations of optical pumping are evident, the Stokes parameters do not vary by more than +or-4% from the weak intensity limit. © 1990 IOP Publishing Ltd.