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

A configuration interaction (CI) model to treat confined many-electron syst ems is presented. Our model proposes a spatially confined linear combinatio n 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 a tom is enclosed within a spherical cavity with infinite potential walls. Co mparisons with other results in the literature are made in order to verify our model.