Laser cooling with intermediate state of spin-orbit coupling of LuF molecule

This work presents a theoretical study of the laser cooling feasibility of the molecule LuF, in the fine structure level of approximation. An ab-initio complete active space self-consistent field (CASSCF)/MRCI with Davidson correction calculation has been done in the Λ^(±) and Ω^(±) representations. The corresponding adiabatic potential energy curves and spectroscopic parameters have been investigated for the low-lying electronic states. The calculated values of the internuclear distances of the X³Σ₀₊ and (1)³Π₀₊ states show the candidacy of the molecule LuF for direct laser cooling. Since the existence of the intermediate (1)³Δ₁ state cannot be ignored, the investigation has been done by taking into consideration the two transitions (1)³Π₀₊-(1)³Δ₁ and (1)³Π₀₊ -X³Σ₀₊. The calculation of the Franck-Condon factors, the radiative lifetimes, the total branching ratio, the slowing distance, and the laser cooling scheme study prove that the molecule LuF is a good candidate for Doppler laser cooling.