Localized Hole Effects in Inner-Shell Excitation

摘要

Ab initio calculations of valence shell ionization potentials have shown that orbital relaxation and correlation differences usually make contributions of comparable magnitude. In marked contrast to this observation is the situation for deep core ionization, where correlation differences (approx. 1 eV) play a relatively minor role compared to orbital relaxation (approx. 20 eV). Theoretical calculations have shown that this relaxation is most easily described if the 1s-vacancy created by a K-shell excitation is allowed to localize on one of the atomic centers. For molecules possessing a center of inversion, this means that the molecular orbitals that best describe the final state do not transform as any irreducible representation of the molecular point group. Recent experimental work by Shaw, King, Read and Cvejanovic and by Stefani and coworkers has prompted us to carry out further calculations on N sub 2 , as well as analogous investigations of 1s/sub N/ implies pi * excitation in NO and N sub 2 O. The generalized oscillator strengths display a striking similarity and point to the essential correctness of the localized hole picture for N sub 2 . The theoretical calculations are briefly described, followed by a summary of the results and comparison to experiment, followed by a short discussion. (ERA citation 09:001439)