Many-body calculation of the core hole spectrum of PdN 2

Abstract

To investigate the dependence of ligand (adsorbate) core hole spectra on the electronic structure of the metal substrate, we performed the ab initio 2h 1 p and 2h2p/2h2p CI calculations of the core hole spectra of linear PdN 2 molecule, using an extended basis set. The main line is the one hole state and takes a much larger intensity than for NiN 2. As in the case of NiN 2 the core hole energy splitting is due to two inequivalent atoms and the magnitude of the energy splitting reflects the metalligand bond strength. As in the case of NiCO, iN 2 and PdCO, also for PdN 2 the π charge transfer (CT) shakeup satellite of a small intensity is obtained near the main line peak. The most striking spectral feature of the core hole spectra of PdN 2 which differs from that for NiCO and NiN 2 is the absence of the 5 eV giant σ shakeup satellite. As in the case of NiCO and PdCO, the π to π* shakeup satellites are obtained at 7 to 9 eV. The present ab initio calculations confirm the mechanism for the interplay between the π and σ shakeup excitations in the ligand core hole spectra which was proposed recently by the authors. This mechanism explains the changes in the core hole spectral features due to changes of ligand and substrates in terms of the different degree of the dσ-s hybridization and s-dσ promotion in the local metal configuration in the ground and ionized states.