The feasibility of laser cooling: an investigation of ab initio of 88Sr35Cl including the hyperfine structure

Abstract

ABSTRACT A promising laser cooling candidate molecule is essential for laser cooling experiments. In this study, the possibility of laser cooling an 88Sr35Cl molecule is investigated using an ab initio method. Seven low-lying Λ-S and six Ω electronic states of the 88Sr35Cl molecule are calculated at a multi-reference configuration interaction level of theory. Spectral constants of bound states of fitted values are in good agreement with experimental values, which are better than the previously obtained theoretical data for higher excitation states. The resulting permanent and transition dipole moments near the equilibrium bond length are close to the theoretical values. Potential energy curves and transition dipole moments are used for obtaining highly diagonally distributed Franck-Condon factors for the A2Π → X2Σ+ transition using the LEVEL program. A short radiative lifetime of the A2Π state is determined; a laser cooling scheme is designed in the vibration level that requires a cooling main laser beam and two repumping laser beams. Transition spectral data of hyperfine energy levels with errors relative to the experimental data do not exceed −0.25∼0.19 MHz when using a quantum effective Hamiltonian approach. This study provides a helpful reference for experimental observation and operation of laser cooling the 88Sr35Cl molecule.