A configuration interaction model to investigate many-electron systems in cavities

A configuration interaction (CI) model to treat confined many-electron systems is presented. Our model proposes a spatially confined linear combination of configuration interaction (LCCI) functions, built from basis functions that do not satisfy confinement boundary conditions. As an application we have calculated total energies for the He ground state, assuming that the atom is enclosed within a spherical cavity with infinite potential walls. Comparisons with other results in the literature are made in order to verify our model. (author). Letter-to-the-editor