ASSIGNING X-RAY-ABSORPTION SPECTRA BY MEANS OF SOFT-X-RAY EMISSION-SPECTROSCOPY

The possibility to symmetry assign x-ray absorption spectra using x-ra y emission spectroscopy is demonstrated. The oxygen K spectra of CO2 a re used to illustrate the possibility to assign core excitations throu gh excitation-energy and angular dependence of resonantly excited x-ra y emission spectra. The Rydberg-associated structures just below the i onization threshold in the O K x-ray absorption spectrum are assigned to be mainly due to excitations to orbitals of sigma(g) character. The results, which contradict some previous literature assignments, are s upported by quantum-chemical calculations. [S1050-2947(98)08001-9].