An ab initio study of excited states of the phthalocyanine magnesium complex and its cation radical

Excited states of the magnesium phthalocyanine complex [Mg(Pc)] and its cation radical are studied by ab initio configuration interaction with single substitutions (CIS), restricted open-shell CIS (ROCIS) and the extended CIS (XCIS) method. Moderately satisfactory agreement between calculated and observed transitions is obtained, and an assignment of the absorption bands of the radical species is proposed.