High resolution gas phase photoabsorption spectra and multiple-scattering Xα study of PX 3 (X=H, CH 3, CF 3) compounds at the P L 2,3 edge

Abstract

High-resolution P 2p photoabsorption spectra of the three phosphines PH 3, P(CH 3) 3 and P(CF 3) 3 have been obtained using monochromatized synchrotron radiation. MS-Xα calculations are reported for all three molecules for both the P 2p pre-edge and post-edge regions. Except for the pre-edge region of P(CH 3) 3, there is reasonable agreement between theory and experiment. In the pre-edge region, peaks are assigned as transitions from P 2p to antibonding or Rydberg levels. The Rydberg transitions have comparable intensity both to the antibonding transitions and the post-edge resonances in all these molecules. The general trends in the post-edge resonances-from an atomic-like delayed onset shape resonance for PH 3 to a molecular orbital or ligand-induced potential barrier shape resonance for P(CF 3) 3 — can be rationalized considering the electronegativity of the ligands.