Theoretical study of the electronic structure with dipole moment calculations of barium monofluoride

The potential energy curves have been investigated for the 41 lowest doublet and quartet electronic states in the ^2s+1Λ^± representation below 55,000 cm^–1 of the molecule BaF via CASSCF and MRCI (single and double excitations with Davidson correction) calculations. Twenty-five electronic states have been studied here theoretically for the first time. The crossing and avoided crossing of 20 doublet electronic states have been studied in the region 30,000–50,000 cm⁻¹. The harmonic frequency ω_e, the internuclear distance R_e, the rotational constant B_e, the electronic energy with respect to the ground state T_e, and the permanent and transition dipole moments have been calculated in addition to static dipole polarizability of the ground state. By using the canonical functions approach, the eigenvalue E_v, the rotational constant B_v, and the abscissas of the turning points R_min and R_max have been calculated for the electronic states up to the vibrational level v=98. The comparison of these values with the theoretical results available in the literature shows a very good agreement. - Highlights: • We report 41 molecular states for the BaF molecule. • The spectroscopic constants have been calculated for the 41 low-lying states. • A ro-vibrational study have been performed up to the vibrational level v=98. • The permanent dipole moments have been investigated for 39 electronic states. • We present 25 new low-lying doublet and quartet excited states.