Two-photon Raman transition channels of NaCs predicted from ab initio calculations

Obtaining effective spontaneous radiative transition channels is a fundamental topic in the preparation of ultracold rovibrational ground states of molecules. Herein, the ranges of prospective transition channels in the NaCs dimer are predicted via exploring the complex energy level structure and transition properties. The potential energy curves of {Λ}-S states and {Ω} states, spectroscopy constants, absolute energies of bound states, and transition information (Frank-Condon factors, lifetimes, transition dipole moments) have been researched. With this purpose, the results of our experiment on binding energies of the b³Π₀⁺ rovibrational states are analyzed; the transition from the higher (photoassociated) ¹Π state to the ground X¹Σ⁺ state is discussed. The wavelengths of the two lasers are predicted as 622.8-656.7 nm and 896.3-969.8 nm with the B¹Π₁ and c³Σ₁⁺ states, respectively, for the stimulated raman adiabatic passage method.