Ab initio calculations and spectral simulation of the [formula omitted] photodetachment process

Abstract

Geometry optimization and harmonic vibrational frequency calculations were performed on the X ˜ 2 A ′ state of P 2 H and X ˜ 1 A ′ state of P 2 H − at the MP2, B3LYP, QCISD and CCSD levels. Franck–Condon factors were computed to simulate the recently observed, photoelectron spectrum of the P 2 H − anions [K. M. Ervin and W. C. Lineberger, J. Chem. Phys. 122 (2005) 194303]. The theoretical spectra obtained by employing density-functional theory (DFT) with 6-311+G(2p,d) values are in excellent agreement with the observed one. In addition, Franck–Condon analyses and spectral simulations confirm the assignment of the observed spectrum to the X ˜ 2 A ′ − X ˜ 1 A ′ photodetachment process of P 2 H −. Using iterative Franck–Condon analysis procedure in the spectral simulations, it is concluded that the reliable variation of geometry is 0.0026 nm for bond length R(PP), 0.0068 nm for bond length R(PH), and 8.3 ° for bond angle ∠( PPH) from X ˜ 2 A ′ state of P 2 H to X ˜ 1 A ′ state of P 2 H −.