Born–Oppenheimer potential energy curves of NaK from the optimised atomic basis sets.

The article presents adiabatic potential energy curves of the ground and excited electronic states for the diatomic NaK molecule. The calculations were made using the ab initio computational methods to include electron correlation. The studied molecule was calculated as the effective two-electron problem, in which only the valence electrons of the molecule are explicitly taken into account. The remaining electrons with atomic nuclei are described with appropriate, energy-consistent relativistic pseudopotentials. Additionally, a bespoke basis set, generated and optimised for both ground and excited electronic states of the NaK system was developed. The spectroscopic parameters of the calculated potential energy curves were determined and compared with the available experimental and theoretical results. The compliance of the obtained results, despite slight differences, is very satisfactory. [ABSTRACT FROM AUTHOR]