Analytical potential energy functions for CO+ in its ground and excited electronic states

Abstract Accurate functions to analytically represent the potential energy interactions of CO+ diatomic system in X 2∑+, A2∏ and B 2∑+electronic states are proposed. The new functions depend upon only four parameters directly obtained from experimental data, without any fitting procedure. These functions have been developed from the modified generalized potential proposed by Araújo and Ballester [Phys. Scr. 96, 125407 (2021)]. The function for the X 2∑+ electronic state represents a significant improvement to the previously proposed model. To quantify the accuracy of the potential energy functions, the least-squares Z-test method, proposed by Murrell and Sorbie, is used. Furthermore, the main spectroscopic constants and vibrational energy levels are calculated and compared for all potentials. The present results agree excellently with the experiment Rydberg-Klein-Rees (RKR) potentials.