title: Absolute measurements and theoretical calculations of photoionization cross sections along the isonuclear sequence of multiply charged barium ions.
abstract: Photoionization of multiply charged ions of the Ba isonuclear sequence up to Ba6+ has been studied in a beam-beam experiment. A very strong increase in the resonance structures was observed when moving from Ba2+ to Ba6+. Absolute values of the photoionization cross sections were measured for Ba2+ and Ba3+ ions. The interpretation of the results is provided using theoretical multiconfiguration Dirac-Fock and relativistic random phase approximation calculations, showing that the collapse of the nf orbitals occurs for Ba4+.
authors.affiliation: Laboratoire de Spectroscopie Atomique et Ionique, Unité Mixte du CNRS No. 8624, Université Paris-Sud, Bâtiment 350, 91405 Orsay, France.
authors.forename: J M
authors.initials: JM
authors.lastname: Bizau
authors.forename: D
authors.initials: D
authors.lastname: Cubaynes
authors.forename: J M
authors.initials: JM
authors.lastname: Esteva
authors.forename: F J
authors.initials: FJ
authors.lastname: Wuilleumier
authors.forename: C
authors.initials: C
authors.lastname: Blancard
authors.forename: J
authors.initials: J
authors.lastname: Bruneau
authors.forename: J P
authors.initials: JP
authors.lastname: Champeaux
authors.forename: A
authors.initials: A
authors.lastname: Compant La Fontaine
authors.forename: C
authors.initials: C
authors.lastname: Couillaud
authors.forename: R
authors.initials: R
authors.lastname: Marmoret
authors.forename: C
authors.initials: C
authors.lastname: Rémond
authors.forename: D
authors.initials: D
authors.lastname: Hitz
authors.forename: M
authors.initials: M
authors.lastname: Delaunay
authors.forename: N
authors.initials: N
authors.lastname: Haque
authors.forename: P C
authors.initials: PC
authors.lastname: Deshmukh
authors.forename: H L
authors.initials: HL
authors.lastname: Zhou
authors.forename: S T
authors.initials: ST
authors.lastname: Manson