Xanes of the Pd and Pt atoms in square and octahedral chloride complexes

Abstract

The fine structure near the ionization threshold in metal X-ray L-absorption spectra of the clusters PdCl 2− 4, PtCl 2− 4, PdCl 2− 6 and PtCl 2− 6 simulating solid complex compounds of the type K 2PdCl 4 and so on has been calculated using the SCF Xα SW method. Pt L 3 absorption spectra for the complexes K 2PtCl 4 and K 2PtCl 6 have been obtained using synchrotron radiation. The pre-edge white line and the near-edge fine structure (XANES) in Pd and Pt spectra of these square and octahedral chloride complexes have been shown to arise, respectively, from electron excitation to a vacant bound molecular orbital (e g for octahedral and b 1g for square complexes) and from photoelectron resonance elastic scattering by the metal atom and its first coordination sphere. The calculations indicated no intense pre-edge transitions for the metal L 1 spectra of these complexes and the XANES was shown to be due to several intense narrow shape resonances of the t 1u and a 2u, e u for octahedral and square complexes, respectively.