High-resolution gas-phase core-level X-ray photoelectron spectroscopy of PH 3 and H 2S with a synchrotron source: observations of vibrational structure on resolved spin—orbit core (2p) lines

Abstract

High-resolution core-level photoelectron spectroscopy of PH 3 and H 2S gave well-resolved spin—orbit components (Δ s.o. PH 3 860 meV, H 2S, 1210 meV). The v′ = 1 vibrational components of PH 3 were clearly discernable (299 meV, 2411 cm −1). The vibrationally excited component on the core (2p) photoelectron lines of PH 3 is weaker than that for SiH 4. For PH 3 the v′ = 1 band is 19% of the v′ = 0 fundamental in the 2p photoelectron spectrum. For H 2S the vibrational component was so weak it could not be reliably extracted. An approximate spectral moment analysis of PH 3 indicated a bond shortening of 0.08 Å (versus an estimate of 0.17 Å shortening for SiH 4, which showed a much stronger vibrationally excited profile, by the same method). The lesser bond shortening on core ionization accounts for the reduced vibrational excitation in the spectrum of PH 3.