Estimates for the interaction potential between two atoms

We consider a quantum system consisting of two electrons in the Coulomb field of two immovable nuclei spaced at a fixed distance, which is considered the problem parameter. We use spectral theory methods to obtain estimates of the system ground-state energy as a function of the internuclear distance. We obtain part of the results under the assumption that the Coulomb interaction constant between different atoms is small. We discuss the importance of the presented investigation for quantum chemistry.