Analytic functions for potential energy curves, dipole moments, and transition dipole moments of LiRb molecule

•LiRb was studied by MRCI with basis sets aug-cc-pwCV5Z for Li and ANO for Rb.•The Re and De for X1Σ+ and a3Σ+ states are in agreement with the experiment values.•The single point energies are fitted into analytic function using MLR function.•The DMs and TDMs are fitted into analytic function.

The analytic potential energy functions (APEFs) of the X1Σ+, 21Σ+, a3Σ+, and 23Σ+ states of the LiRb molecule are obtained using Morse long-range potential energy function with damping function and nonlinear least-squares method. These calculations were based on the potential energy curves (PECs) calculated using the multi-reference configuration interaction (MRCI) method. The reliability of the APEFs is confirmed using the curves of their first and second derivatives. By using the obtained APEFs, the rotational and vibrational energy levels of the states are determined by solving the Schrödinger equation of nuclear movement. The spectroscopic parameters, which are deduced using Dunham expansion, and the obtained rotational and vibrational levels are compared with the reported theoretical and experimental values. The correlation effect of the electrons of the inner shell remarkably improves the results compared with the experimental spectroscopic parameters. For the first time, the APEFs for the dipole moments and transition dipole moments of the states have been determined based on the curves obtained from the MRCI calculations.

Graphical abstractThe present APEF based on MLR function and ab initio PEC has significantly improved in comparison with the experimental data, in particular in the repulsive section.Figure optionsDownload full-size imageDownload as PowerPoint slide