Theoretical study on the low-lying electronic states of SbF

Multi-reference configuration interaction calculations are carried out to elucidate the distribution of low-lying valence and Rydberg states of antimony monofluoride (SbF) below 50000 cm⁻¹, where the effects of core–valence correlation and spin–orbit coupling have been employed. From the potential energy curves, the spectroscopic constants of seven (quasi-)bound $\Lambda$-S and fourteen (quasi-)bound $\Omega$ states have been derived, which agree well with the experimental values. Our results show that the second ${}^3\Pi$ state involves the occupation on the Rydberg shell 6$s$ of Sb, which settles the assignment of the so-called “$C_2$” and “$C_{3}1$” states in the ultraviolet spectra of SbF. With the help of the more accurate coupled cluster calculations, the dissociation energy ($D_e$) of SbF is determined to be 4.24 eV at the theoretical limit, being 0.2 eV smaller than the widely used empirical value in the literature.