Eur. Phys. J. D (2016) 70: 244
https://doi.org/10.1140/epjd/e2016-70388-9

Regular Article

Potential energy curves and spectroscopic parameters of the 24 Λ-S states and 54 Ω states of the F₂⁺ cation including the spin-orbit coupling effect^*

¹ College of Physics and Material Science, Henan Normal University, Xinxiang 453007, P.R. China
² College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, P.R. China

^a e-mail: scattering@sina.com.cn

Received: 14 June 2016
Received in final form: 15 August 2016
Published online: 17 November 2016

Abstract

This work calculated the PECs of 24 Λ-S states and 54 Ω states of F₂⁺ cation. The calculations were done with the CASSCF method, which was followed by the internally contracted MRCI approach. Core-valence correlation correction, scalar relativistic correction and basis set extrapolation were taken into account. Of these 24 Λ-S states, the 2²Σ_g⁻, 2²Σ_u⁻, 2⁴Σ_g⁻, 1⁴Δ_u, and 2⁴Π_g states were found to be repulsive. The X²Π_g, A²Π_u 1⁴Δ_g, 1⁴Π_g and 2⁴Π_g states were found to be inverted with the spin-orbit coupling effect included. The 1²Δ_g, 2⁴Π_u, 1⁴Π_g, 1⁴Σ_u⁺, 2²Π_u, 1⁴Σ_g⁻, 2⁴Σ_u⁻, and 1²Σ_g⁺ states were found to be weakly bound. The 2⁴Σ_u⁻ state had double wells. The avoided crossings of PECs were observed between the A²Π_u and 2²Π_u states, the X²Π_g and 2²Π_g states, the 1²Σ_u⁻ and 2²Σ_u⁻ states, the 1⁴Π_u and 2⁴Π_u states, and the 1⁴Σ⁻_g and 2⁴Σ⁻_g states. Some spectroscopic parameters were determined and the vibrational properties of several weakly-bound states were predicted. The spin-orbit coupling effect on the spectroscopic parameters was evaluated. Comparison with available experimental data shows that the methodology used in this paper is highly accurate for this system.