Relativistic calculations of the potential energy curve and QED-corrections for the ground state of the CO molecule

A non-empirical relativistic calculation of the potential energy curve of the ground $X^1\Sigma^+$ state of the carbon monoxide (CO) molecule in the internuclear distances range $R_{AB}\in$[0.5, 30.0] a.u. is performed. The calculation is carried out by the multireference configuration-interaction method in the basis of the Dirac–Fock–Sturm orbitals. For the entire specified range of distances, multi-electron quantum-electrodynamic corrections to the CO energy are calculated by the method of the model Lamb shift operator. The contributions of the quantum electrodynamic corrections to the value of the equilibrium internuclear distance $R_{AB}^e$, the dissociation energy $D_e$ and the vibrational constant $\omega_e$ of the CO molecule are obtained.