title: Few-photon multiple ionization of N2 by extreme ultraviolet free-electron laser radiation.
abstract: Few-photon multiple ionization of N2 was studied differentially in a reaction microscope using 44 eV, approximately 25 fs, intense ( approximately 10(13) W/cm(2)) photon pulses from FLASH. Sequential ionization is observed to dominate. For various intermediate charge states N(2)(n+0 we find a considerable excess of photons absorbed compared to the minimum number that would energetically be required. Photoionization of aligned N(2)(n+) ions, produced by photon absorption in sequential steps, is explored and few-photon absorption pathways are traced by inspecting kinetic energy releases and fragment-ion angular distributions.
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: Y H
authors.initials: YH
authors.lastname: Jiang
authors.forename: A
authors.initials: A
authors.lastname: Rudenko
authors.forename: M
authors.initials: M
authors.lastname: Kurka
authors.forename: K U
authors.initials: KU
authors.lastname: Kühnel
authors.forename: Th
authors.initials: T
authors.lastname: Ergler
authors.forename: L
authors.initials: L
authors.lastname: Foucar
authors.forename: M
authors.initials: M
authors.lastname: Schöffler
authors.forename: S
authors.initials: S
authors.lastname: Schössler
authors.forename: T
authors.initials: T
authors.lastname: Havermeier
authors.forename: M
authors.initials: M
authors.lastname: Smolarski
authors.forename: K
authors.initials: K
authors.lastname: Cole
authors.forename: R
authors.initials: R
authors.lastname: Dörner
authors.forename: S
authors.initials: S
authors.lastname: Düsterer
authors.forename: R
authors.initials: R
authors.lastname: Treusch
authors.forename: M
authors.initials: M
authors.lastname: Gensch
authors.forename: C D
authors.initials: CD
authors.lastname: Schröter
authors.forename: R
authors.initials: R
authors.lastname: Moshammer
authors.forename: J
authors.initials: J
authors.lastname: Ullrich