MRCI study on the potential energy curves and spectroscopic parameters of the ground and low-lying excited states in CaF

The potential energy curves (PECs) of the ground and five low-lying excited states of CaF have been calculated using the internally contracted multireference configuration interaction method (MRCI) with a large contracted basis set cc-pvNz (N = t, q, 5) for atoms Ca and F and extrapolate to complete basis set (CBS). Based on the PECs, the spectroscopic terms, spectroscopic parameters have been determined. The present results are in good agreement with the experimental data available at present, and better than the theoretical results in the literature, although the present equilibrium positions are a little larger. We also calculate the vibrational levels for each state, and they are in excellent agreement with the experimental data. It implies that the method to determine the molecular properties through calculating PECs and solving the Schrödinger equation of nuclear motion is effective for CaF molecule.