title: Rydberg state ionization by half-cycle-pulse excitation: strong kicks create slow electrons.
abstract: The asymptotic velocity distribution of electrons ionized in half-cycle-pulse excitation of high Rydberg states (n=34), placed in a static electric field, is studied using electron velocity-map imaging. At weak half-cycle pulse strengths, the electrons escape over the saddle point in the potential. For strong half-cycle pulses, the electrons are emitted in the direction of the field kick. The much slower and less intense half cycle of opposite polarity, which necessarily follows the main half-cycle pulse, strongly affects the momentum distribution and reduces the excess energy of the electrons significantly.
authors.affiliation: Fom Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Wetzels
authors.forename: A
authors.initials: A
authors.lastname: Gürtler
authors.forename: L D
authors.initials: LD
authors.lastname: Noordam
authors.forename: F
authors.initials: F
authors.lastname: Robicheaux
authors.forename: C
authors.initials: C
authors.lastname: Dinu
authors.forename: H G
authors.initials: HG
authors.lastname: Muller
authors.forename: M J J
authors.initials: MJ
authors.lastname: Vrakking
authors.forename: W J
authors.initials: WJ
authors.lastname: van der Zande