title: Towards a pair natural orbital coupled cluster method for excited states.
abstract: The use of back-transformed pair natural orbitals in the calculation of excited state energies, ionization potentials, and electron affinities is investigated within the framework of equation of motion coupled cluster theory and its similarity transformed variant. Possible approaches to a more optimal use of pair natural orbitals in these methods are indicated.
authors.affiliation: Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Achintya Kumar
authors.initials: AK
authors.lastname: Dutta
authors.affiliation: Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Neese
authors.affiliation: Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Róbert
authors.initials: R
authors.lastname: Izsák