SCREENING IN RESONANT X-RAY-EMISSION OF MOLECULES

We explore the effects of screening in resonant X-ray emission from mo lecules by means of unconstrained multiconfigurational self-consistent field optimizations of each state involved in the resonant and nonres onant X-ray processes. It is found that, although screening can produc e shifts in transition energies of a few eV, its effect on the transit ion intensities is relatively minor. Using results from the investigat ed molecules, we find that the screening is quite dependent on the typ e of molecule-saturated versus unsaturated-and on the core site, but d epends little on the particular core shell for a given core site. A di fferential core level screening, relating to the X-ray chemical shift, can still be noted. The consequence of the findings for analysing gen eral resonant X-ray emission spectra is discussed.