Accuracy of the new modified Morse potential energy function for ground and excited states of diatomic molecules

This paper presents a detailed study on the performance of the new modified Morse potential in representing the vibrational motion of several diatomic molecules. The matrix Numerov method has been used to solve the time-independent Schrödinger equation for the new modified Morse potential, Morse potential, and Varshni potential. The vibrational energy eigenvalues of the 20 diatomic molecules in various electronic states were calculated. The vibrational energy eigenvalues and anharmonicity constants calculated using the new modified Morse potential were closer to the experimental values for all 20 molecules than the eigenvalues calculated from the Morse and Varshni potential functions. [Display omitted] •Vibrational levels of 20 diatomic molecules using Morse, Varshni, and NMM potentials.•NMM is more accurate for vib. levels and anharmonicity constant than Morse, Varshni.•Overall, the Varshni potential yields more accurate vibrational levels than Morse.•Morse is more accurate for anharmonicity constant than Varshni for several molecules.