title: Multiple ionization of rare gas atoms irradiated with intense VUV radiation.
abstract: The interaction of intense vacuum-ultraviolet radiation from a free-electron laser with rare gas atoms is investigated. The ionization products of xenon and argon atomic beams are analyzed with time-of-flight mass spectroscopy. At 98 nm wavelength and approximately 10(13) W/cm(2) multiple charged ions up to Xe6+ (Ar4+) are detected. From the intensity dependence of multiple charged ion yields the mechanisms of multiphoton processes were derived. In the range of approximately 10(12)-10(13) W/cm(2) the ionization is attributed to sequential multiphoton processes. The production of multiple charged ions saturates at 5-30 times lower power densities than at 193 and 564 nm wavelength, respectively.
authors.affiliation: Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany. wabnitz@drecam.cea.fr
authors.forename: H
authors.initials: H
authors.lastname: Wabnitz
authors.forename: A R B
authors.initials: AR
authors.lastname: de Castro
authors.forename: P
authors.initials: P
authors.lastname: Gürtler
authors.forename: T
authors.initials: T
authors.lastname: Laarmann
authors.forename: W
authors.initials: W
authors.lastname: Laasch
authors.forename: J
authors.initials: J
authors.lastname: Schulz
authors.forename: T
authors.initials: T
authors.lastname: Möller