title: Size dependent fragmentation of argon clusters in the soft x-ray ionization regime.
abstract: Photofragmentation of argon clusters of average size ranging from 10 up to 1000 atoms is studied using soft x-ray radiation below the 2p threshold and multicoincidence mass spectroscopy technique. For small clusters (<N>=10), ionization induces fast fragmentation with neutral emission imparting a large amount of energy. While the primary dissociation takes place on a picosecond time scale, the fragments undergo slow degradation in the spectrometer on a microsecond time scale. For larger clusters (<N> >or=100) we believe that we observe the fragmentation pattern of multiply charged species on a time-scale which lasts a few hundred nanoseconds. The reason for these slower processes is the large number of neutral atoms which act as an efficient cooling bath where the excess energy ("heat") dissipates among all degrees of freedom. Further degradation of the photoionic cluster in spectrometer then takes place on the microsecond time scale, similar to small clusters.
authors.affiliation: MAX-lab, Lund University, P.O. Box 118, S-221 00 Lund, Sweden.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Gisselbrecht
authors.forename: Andreas
authors.initials: A
authors.lastname: Lindgren
authors.forename: Florian
authors.initials: F
authors.lastname: Burmeister
authors.forename: Maxim
authors.initials: M
authors.lastname: Tchaplyguine
authors.forename: Gunnar
authors.initials: G
authors.lastname: Ohrwall
authors.forename: Magnus
authors.initials: M
authors.lastname: Lundin
authors.forename: Arnaldo Naves
authors.initials: AN
authors.lastname: de Brito
authors.forename: Svante
authors.initials: S
authors.lastname: Svensson
authors.forename: Olle
authors.initials: O
authors.lastname: Björneholm
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Sorensen