ON THE RESONANTLY CORE-EXCITED STATES OF THE N2 NI AND RELATED SYSTEMS/

The 1s to pi resonant excitation oscillator strengths and energies of the inner and outer N atomic sites of NiN2 have been calculated by th e 2h2p/2h2p CI scheme, using the core excited state SCF relaxed orbita ls. A comparison is made with previous theoretical results obtained by using the same CI scheme but with the neutral ground state orbitals o r the core ionized state SCF relaxed orbitals. The oscillator strength ratio for the inner and outer N atoms is reversed in comparison to pr evious results. The strength reflects the empty N 2p occupation of the pi orbital at the excitation atomic site in the ground state. Use of the core ionized state relaxed orbitals fails because of the larger c ore relaxation in comparison to the core excited state. The influence of the core relaxation in the resonantly excited state on the spectral features of the DES spectra with variations of adsorbate/substrate sy stems is also discussed.