Ab initio CI calculations on potential energy curves of low-lying states of BrF and its cation including spin–orbit coupling

摘要

Bromine monofluoride (BrF) and its cation (BrF+) have attracted much scientific attention because of their potential significance in the stratospheric ozone depletion and the development of chemical laser. Despite that the structure and spectroscopic properties of the 1~3∏_(0+) (B~3∏_(0+)) and 1~3∏_1 states of BrF have been experimentally investigated in the literature, theoretical investigations of BrF and its cation are relatively sparse. In this paper, the low-lying electronic states for BrF/BrF~+ were studied by means of relativistic multireference configuration interaction method (including Davidson correction). The spin–orbit coupling effect was considered by the state-interacting method with the full Breit-Pauli Hamiltonian. For BrF, the potential energy curves (PECs) of 12 Λ–S states and 23 ? states generated from the Λ–S states were calculated. The avoided crossing mechanism of ? = 0~+ states were analyzed by the variations of dominant Λ–S composition for ? states at several different internuclear distances. For BrF+, the PECs of the ground states (X~2∏_(3/2) and X~2∏_(1/2)) were computed. The spectroscopic constants of the bound states of BrF/BrF~+ were determined, which are in good agreement with previously available experimental results. Finally, the ionization energies from the neutral ground state (X~1Σ~+) to different ionic states (X~2∏_(3/2), and X~2∏_(1/2)) were obtained.