Eur. Phys. J. D (2015) 69: 59
https://doi.org/10.1140/epjd/e2015-50584-y

Regular Article

Extensive ab initio calculation on low-lying excited states of SiN⁺ cation including spin-orbit coupling

College of Physics and Electronic Engineering, Henan Normal University, Xinxiang 453007, P.R. China

^a e-mail: yf-liu@htu.cn

Received: 7 August 2014
Received in final form: 26 December 2014
Published online: 3 March 2015

Abstract

Electronic structures and transition properties of the SiN⁺ molecule are investigated by performing ab initio calculations based on scalar relativistic multireference configuration interaction (MRCI) method plus Davidson correction (+Q). The potential energy curves (PECs) for the 22 Λ-S electronic states of the SiN⁺ are obtained. The spectroscopic constants of the bound states are determined, where good agreements with the available spectroscopic data are achieved. Spin-orbit coupling (SOC) effect is introduced via the state interaction approach with the full Breit-Pauli Hamiltonian operator for the state X³Σ⁻, a³Π, ⁵Σ⁻ and ⁵Π. This is the first time that SOC calculation has been carried out on the SiN⁺. The four states split into 15 Ω states after the consideration of the SOC effect. The SOC effect, leading to some avoided crossings, is found to be substantial for the SiN⁺. Moreover, the transition dipole moments (TDMs) and Franck-Condon factors are derived. Finally, the corresponding radiative lifetimes of the a³Π₁ state are evaluated.