Relativistic calculations on the transition electric dipole moments and radiative lifetimes of the spin-forbidden transitions in the antimony hydride molecule

Calculations on the spectroscopic constants and transition properties of the first three states (\rm a^1\Delta , \rm b^1\Sigma^+, and X^3\Sigma^-) of the SbH molecule were performed under the relativistic framework using the exact two-component Hamiltonian (X2C). The potential energy curves in the Franck-Condon region were computed and compared with the previous values. Furthermore, the transition dipole moments for the weak spin-forbidden transitions (\rm b0^+-X_10^+, \rm b0^+-X_21, X_10^+-X_21, and X_21-\rm a2) were reported. The spontaneous radiative lifetime of the \rm b^1\Sigma^+ (\upsilon '=0) state was calculated as 163.5 \pm 7.5 μs, which is in reasonable agreement with the latest experimental value of 173 \pm 3 μs. The spontaneous radiative lifetimes of the X_21 (\upsilon '=0) state and the \rm a2 (\upsilon '=0) state were calculated to be 48.6 s and \sim 8 ms, respectively. Our study is expected to be a benchmark transition property computation for comparison with other theoretical and experimental results. The datasets presented in this paper, including the transition dipole moments, are openly available at https://dx.doi.org/10.11922/sciencedb.j00113.00018.