title: Theoretical investigations on CaO ions: vibronic states and photoelectron spectroscopy.
abstract: The low-lying electronic states, X(2)Π and A(2)Σ(+) of CaO(+) and X(2)Σ(+) and A(2)Π of CaO(-), have been determined at the MRCI+Q level of theory with the aug-cc-pV5Z(O) and cc-pCV5Z(Ca) basis sets. The two states of CaO(+) are close within <0.1 eV and coupled via spin-orbit effect. The X(2)Σ(+) and A(2)Π states of CaO(-) are energetically separated by <1 eV such that the first excited state is close to the electronic ground state of neutral CaO and unstable with respect to electron detachment. Using the potential energy curves and the spin-orbit coupling terms, the vibronic energy levels of these ions have been determined. The ionization energy and the electron affinity of CaO are calculated at 6.79 and 0.79 eV, respectively. The photoelectron spectra of CaO(-) and CaO have also been simulated.
authors.affiliation: Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS , 5 bd Descartes, 77454 Marne-la-Vallée, France.
authors.forename: H
authors.initials: H
authors.lastname: Khalil
authors.forename: F
authors.initials: F
authors.lastname: Le Quéré
authors.forename: C
authors.initials: C
authors.lastname: Léonard
authors.forename: V
authors.initials: V
authors.lastname: Brites