Detection of neutral metastable fragments from electron-impact on argon clusters

van der Burgt, P. J. M.; McConkey, J. W.
June 1995
Journal of Chemical Physics;6/1/1995, Vol. 102 Issue 21, p8414
Academic Journal
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 n=2 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 n=1 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. © 1995 American Institute of Physics.


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