Analytical potential energy function for the electronic states 2∏1/2 and 2∏3/2 of Ox2 (x = +1, −1)

The splitting of potential energy levels for ground state X2∏g of Ox2 (x = +1, −1) under spin—orbit coupling (SOC) has been calculated by using the spin-orbit (SO) multi-configuration quasi-degenerate perturbation theory (SO-MCQDPT). Their Murrell–Sorbie (M–S) potential functions are gained, and then the spectroscopic constants for electronic states 2∏1/2 and 2∏3/2 are derived from the M–S function. The vertical excitation energies for Ox2 (x = +1, −1) are v[O+12 (2∏3/2 → X2∏1/2)] = 195.652cm−1, and v[O−12(2∏1/2 → X2∏3/2)] = 182.568cm−1, respectively. All the spectroscopic data for electronic states 2∏1/2 and 2∏3/2 are given for the first time.