title: Optimal virtual orbitals to relax wave functions built up with transferred extremely localized molecular orbitals.
abstract: Extremely localized molecular orbitals (ELMOs), namely orbitals strictly localized on molecular fragments, are easily transferable from one molecule to another one. Hence, they provide a natural way to set up the electronic structure of large molecules using a data base of orbitals obtained from model molecules. However, this procedure obviously increases the energy with respect to a traditional MO calculation. To gain accuracy, it is important to introduce a partial electron delocalization. This can be carried out by defining proper optimal virtual orbitals that supply an efficient set for nonorthogonal configurations to be employed in VB-like expansions.
authors.affiliation: Dipartimento di Chimica Fisica ed Elettrochimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Genoni
authors.forename: Arianna
authors.initials: A
authors.lastname: Fornili
authors.forename: Maurizio
authors.initials: M
authors.lastname: Sironi