HIGH-RESOLUTION GAS-PHASE PHOTOABSORPTION SPECTRA AND MULTIPLE-SCATTERING X-ALPHA STUDY OF PX3 (X = H, CH3, CF3) COMPOUNDS AT THE P-L2,3 EDGE

High-resolution P 2p photoabsorption spectra of the three phosphines PH3, P(CH3)3 and P(CF3)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(CH3)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 PH3 to a molecular orbital or ligand-induced potential barrier shape resonance for P(CF3)3 - can be rationalized considering the electronegativity of the ligands. © 1990.