title: Low-energy nondipole effects in molecular nitrogen valence-shell photoionization.
abstract: Observations are reported for the first time of significant nondipole effects in the photoionization of the outer-valence orbitals of diatomic molecules. Measured nondipole angular-distribution parameters for the 3sigma(g), 1pi(u), and 2sigma(u) shells of N2 exhibit spectral variations with incident photon energies from thresholds to approximately 200 eV which are attributed via concomitant calculations to particular final-state symmetry waves arising from (E1)multiply sign in circle(M1,E2) radiation-matter interactions first-order in photon momentum. Comparisons with previously reported K-edge studies in N2 verify linear scaling with photon momentum, accounting in part for the significantly enhanced nondipole behavior observed in inner-shell ionization at correspondingly higher momentum values in this molecule.
authors.affiliation: Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003, USA.
authors.forename: O
authors.initials: O
authors.lastname: Hemmers
authors.forename: R
authors.initials: R
authors.lastname: Guillemin
authors.forename: D
authors.initials: D
authors.lastname: Rolles
authors.forename: A
authors.initials: A
authors.lastname: Wolska
authors.forename: D W
authors.initials: DW
authors.lastname: Lindle
authors.forename: E P
authors.initials: EP
authors.lastname: Kanter
authors.forename: B
authors.initials: B
authors.lastname: Krässig
authors.forename: S H
authors.initials: SH
authors.lastname: Southworth
authors.forename: R
authors.initials: R
authors.lastname: Wehlitz
authors.forename: B
authors.initials: B
authors.lastname: Zimmermann
authors.forename: V
authors.initials: V
authors.lastname: McKoy
authors.forename: P W
authors.initials: PW
authors.lastname: Langhoff