Ground-state potential and dipole moment of carbon monoxide: Contributions from electronic correlation, relativistic effects, QED, adiabatic correction, and nonadiabatic correction
Д. П. Усов, Y. S. Kozhedub, V. V. Meshkov, A. V. Stolyarov, N. K. Dulaev, А. М. Рыжков, I. M. Savelyev, В. М. Шабаев, I. I. Tupitsyn
Abstract
The ground ${\mathrm{X}\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ state potential energy curve (PEC) and dipole moment curve (DMC) of CO molecule have been revisited within the framework of the relativistic coupled-cluster approach, which incorporates nonperturbative single, double, and triple cluster amplitudes (CCSDT) in conjunction with a finite-field methodology. The generalized relativistic pseudopotential model was used for the effective introducing the relativity in all-electron correlation treatment and accounting the quantum-electrodynamics (QED) corrections within the model-QED-operator approach. The diagonal Born-Oppenheimer correction to PEC has been evaluated using the CCSD approach. The sensitivity of resulting PEC and DMC to variations in basis set parameters and regular intramolecular perturbations were considered as well. The present ab initio results are in a reasonable agreement with their most accurate semiempirical counterparts.