A theoretical electronic structure with a feasibility study of laser cooling of LaNa molecules with a spin orbit effect

The electronic structure with the spin orbit effect of the molecule LaNa has been studied in the present work using the Multi-Reference Configuration Interaction MRCI calculations including Davidson correction (+Q). Adiabatic potential energy curves (PECs) have been investigated for the lowest low-lying spin free states in the Λ representation and spin orbit states of Ω = 0^+/−, 1, 2, 3, and 4 along with their spectroscopic constants R_e, T_e, ω_e, and B_e, the dissociation energy D_e, the dipole moment μ_e, and the ionic character f_ionic of the LaNa molecule at the equilibrium bond length. The permanent dipole moment curves (PDMCs) for the investigated states are calculated in addition to the electronic transition dipole moments between the lowest electronic states where the Franck-Condon factor (FCF) has been calculated for the X¹Σ⁺-1¹Π and for many spin orbit transitions. For these transitions the dipole moments are used in order to determine the Einstein coefficient of spontaneous emission A_ν′ν, the radiative lifetime τ and the branching ratio R_ν′ν. Employing the canonical function approach, the rovibrational parameters E_ν, B_ν, D_ν, R_min and R_max have also been calculated for the lowest vibrational levels of different bound states in both Λ and Ω representations. To the best of our knowledge, the data reported in the present work are presented for the first time in the literature with a discussion on the candidacy of this molecule for laser cooling.