The feasibility of laser cooling: an investigation of ab initio of MgBr, MgI and MgAt molecular.

Abstract

Finding a promising laser cooling candidate molecule is an essential part of laser cooling experiments. The possibility of laser cooling the MgBr, MgI and MgAt molecules is investigated using ab initio method in this paper. Twelve low-lying Λ-S and six Ω electronic states of the MgBr, MgI and MgAt molecule have been calculated at the multi-reference configuration interaction level of theory. The fitted spectral constants of the bound state are in good agreement with previously obtained theoretical and experimental value. The highly diagonally distributed Franck-Condon factors for the A2Π1/2→X2∑1/2+ transition of the MgBr, MgI and 22Π1/2→X2∑1/2+ transition of the MgAt are obtained by using the LEVEL program based on the potential energy curves and transition dipole moments. The short radiative lifetime of the A2Π1/2 of the MgBr, MgI and 22Π1/2 of the MgAt state are determined. Then, we design a laser cooling scheme with one cooling the main laser beam and two repumping laser beams. Finally, the transition spectral data of hyperfine energy level with the errors relative to the experimental data not exceeding 6MHz are evaluated via employing a quantum effective Hamiltonian approach. We hope that a helpful reference can be provided for experimental observation and operation.