van der Burgt, P.J.M. and McConkey, J.W.
Detection of neutral metastable fragments from electron-impact
on argon clusters.
Journal of Chemical Physics, 102.
We have studied the production of neutral metastable fragments in electron collisions with neutral
argon clusters. The fragments are detected using a time-of-flight technique. The time-of-flight
spectra show that the metastable fragments appear in two velocity ranges. Kinetic energy
distributions are obtained, showing that the faster fragments are ejected with energies from 0.2 to
1.5 eV and that the slower fragments have energies less than 0.2 eV. It is argued that the
fragmentation of the clusters involves the excitation and decay of excitons in the clusters.The faster
fragments are produced by n52 excitons, which localize on an excimer or an excited trimer within
the cluster and upon dissociation cause the ejection of a metastable atom. The slower fragments are
produced by n51 excitons, which tend to localize on the periphery of the cluster, leading to the
ejection of a metastable atom due to weak repulsive forces with neighboring atoms. Four different
production mechanisms for neutral metastable fragments are observed.
||argon; atomic clusters; molecular clusters; molecular fragments; metastable states; detection; time-of-flight method; spectra; kinetic energy; distribution; excitation; exitons; dissociation
||Faculty of Science and Engineering > Experimental Physics
Dr Peter van der Burgt
||17 Aug 2010 15:37
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||Journal of Chemical Physics
||American Institute of Physics
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