title: Fluid Flow and Effusive Desorption: Dominant Mechanisms of Energy Dissipation after Energetic Cluster Bombardment of Molecular Solids.
abstract: The angular distribution of intact organic molecules desorbed by energetic C(60) primary ions was probed both experimentally and with molecular dynamics computer simulations. For benzo[a]pyrene, the angular distribution of intact molecules is observed to peak at off-normal angles. Molecular dynamics computer simulations on a similar system show the mechanism of desorption involves fast deposition of energy followed by fluid-flow and effusive-type emission of intact molecules. The off-normal peak in the angular distribution is shown to arise from emission of intact molecules from the rim of a crater formed during the cluster impact. This signature is unique for molecules because fragmentation processes remove molecules that would otherwise eject at directions near-normal to the surface.
authors.affiliation: The Pennsylvania State University, Department of Chemistry, University Park, PA 16802, USA dab390@psu.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Brenes
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Postawa
authors.forename: Andreas
authors.initials: A
authors.lastname: Wucher
authors.forename: Paul
authors.initials: P
authors.lastname: Blenkinsopp
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Garrison
authors.forename: Nicholas
authors.initials: N
authors.lastname: Winograd