Electronic densities in systems with fractionally charged nuclei: a symmetry breaking study

Abstract

This work reports an extension of the recent study on changes of electronic structures in systems possessing nuclei with fractional charges (Cohen and MoriSánchez in J Chem Phys 140:044110, 2014). Using the simple Hückel framework we show that the introduction of fractional charges in molecular systems causes a symmetry breaking which leads to strong changes in the electronic densities respect to their counterpart conventional systems with integer nuclear charges. Numerical determinations in simple one- and two-electron systems within this model are qualitatively compared with the results arising from the full configuration interaction method. The described procedure allows to study ground and excited states as well as the dissociation products when the bond lengths of the molecules are stretched.