Study on Vibrational Rotational Spectroscopic Characteristics of Alkaline Earth Metal Halides Strontium Iodide Molecules

The electronic structure and single point energy of the excited state of strontium iodide (⁸⁸Sr¹²⁷I) molecule are optimized by introducing Davidson, nuclear valence electron correlation and relativistic effect corrections. Based on the optimization calculation results, the potential energy curves and dipole moments of the lowest bound states are analyzed and obtained. The LEVEL8.0 program is developed to fit the corrected potential energy curves and obtain spectral properties parameters such as spectral constants, molecular constants, and vibrational energy levels for each bound state. After comparison, it was found that the calculated results in the paper were in good agreement with the experimental values, which shows that the method in this paper was reliable. Finally, The radiation lifetimes of the lowest two excited states to the ground state transitions were calculated by combining the transition dipole moment, Franck-Condon factor, single point energy and vibration energy level of each electronic state. These spectral characteristic parameters provide theoretical support for further experimental measurement and construction of molecular laser cooling schemes.