title: Ab initio study on the low-lying excited states of gas-phase PH(+) cation including spin-orbit coupling.
abstract: Ab initio calculations have been performed on the low-lying excited and ground states of PH(+). The potential energy curves (PECs) of the Λ-S states were calculated with multi-reference configuration interaction (MRCI) method along with the basis sets at 5-ξ level. In order to improve the PECs, the Davidson(+Q) correction and the Scalar relativistic effect are included. The corresponding spectroscopic constants were determined and good agreements with the available measurement were found. The interactions of the A(2)Δ-(4)Π and 1(2)Σ(+)-(4)Π by the spin-orbit coupling (SOC) effect were well described by the spin-orbit matrix elements. The SOC effect makes the original 8 Λ-S states split into 15Ω states. The Ω=1/2 state generated from the X(2)Π state is confirmed to the ground Ω state. And the SOC splitting for the X(2)Π is calculated to be 294cm(-1). The SOC effect has large effect on the PECs of the A(2)Δ and 1(2)Σ(+) states, leading to much more shallow potential wells as well as potential barriers. The analysis of the wavefunction for the Ω states shows that the strong spin-orbit interaction exists near the crossing points of the PECs for the Λ-S states. The transition dipole moments (TDMs) of transitions A(2)Δ-X(2)Π and 1(2)Σ(-)-X(2)Π are evaluated with the MRCI wavefunction. Based on the TDMs along with the calculated Franck-Condon factors, the radiative lifetimes for the selected vibrational levels of A(2)Δ and 1(2)Σ(-) states are predicted at the microseconds (μs). Good agreement with the measurement shows that the lowest vibrational level for A(2)Δ state is almost uninfluenced by the perturbation via the SOC effect.
authors: Hospital Affiliated of Changchun University of Chinese Medicine, Changchun 130021, China.
authors: Xia
authors: X
authors: Li
authors: Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012, China.
authors: Xiaomei
authors: X
authors: Zhang
authors: Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012, China. Electronic address: yanbing@jlu.edu.cn.
authors: Bing
authors: B
authors: Yan
mesh_terms: D002412:Cations / Q000737:chemistry*; D004583:Electrons; D005740:Gases / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D011789:Quantum Theory; D013057:Spectrum Analysis; D013816:Thermodynamics
chemical_list: D002412:Cations; D005740:Gases; D010720:Phosphines
keywords: MRCI+Q; PH(+); Potential energy curve (PEC); Spectroscopic constants