Eur. Phys. J. D 64, 249-256 (2011)
https://doi.org/10.1140/epjd/e2011-20276-y

Regular Article

Spin-orbit effects in the ground X²Π state and two low-lying excited valence states B²Π and L^′2Φ for NO

¹ Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P.R. China
² School of Civil Engineering and Transportation, South China University of Technology, Guangzhou, Guangdong 510640, P.R. China

^a e-mail: gaotao2010@gmail.com

Received: 11 May 2011
Received in final form: 29 June 2011
Published online: 11 October 2011

Abstract

The potential energy curves and spectroscopic constants B_e, ω_e, ω_eχ_e, α_e, D_e of the six Ω states (X²Π_{1/2,   3/2}, B²Π_{1/2,   3/2} and L^′2Φ_{5/2,   7/2}) of the NO radical molecule were calculated using spin-orbit multi-configuration quasi-degenerate perturbation theory (SO-MCQDPT). The spin-orbit coupling effect was considered via the state interaction approach with the full Breit-Pauli Hamiltonian. The spin-orbit splitting energy between the X²Π_1/2 and X²Π_3/2 states of the NO radical is 129.61 cm^-1, which agrees reasonably well with the experimental value of 123.13 cm^-1. For the B²Π_{1/2,   3/2} states, the spin-orbit coupling (SOC) splitting energy is 35.99 cm^-1, the corresponding experimental value is 31.7 cm^-1. The SOC splitting value of the L^′2Φ_{5/2,   7/2} states was calculated to be 103.2 cm^-1. The spectroscopic constants R_e, ω_e, ω_eχ_e, B_e, α_e, D_e are in reasonable agreement with available experimental and theoretical data for the six Ω states.