Metastable fragmentation of rare gas cluster ions initiated by excimer decay
- Univ. Innsbruck (Austria)
A new unusual metastable fragmentation channel of argon and neon cluster ions produced by electron impact ionization of a neutral cluster beam has been studied with a double focusing sector field mass spectrometer. In contrast to the usual case of statistical single monomer evaporation, in the new metastable fragmentation channel the number of ejected monomers is larger than one, e.g. In the case of argon cluster ions it rises from 2 for the Ar{sub 4}{sup +} up to 10 for the Ar{sub 30}{sup +} parent cluster ion. After studying the dependence of the fragment ion current on (i) the electron energy, (ii) the parent cluster size and the number of ejected monomers, and (iii) the time interval between ion formation and dissociation, the authors concluded that the radiative decay of a metastable excimer Ar{sub 2}{sup *}({sup 3}{Sigma}{sub u}{sup +}) (resp. Ne{sub 2}{sup *}({sup 3}{Sigma}{sub u}{sup +})) localized inside the cluster ion leads to repulsion of Ar(resp. Ne) atoms in the ground state Ar{sub 2}({sup 1}{Sigma}{sub g}{sup +}) (resp. Ne{sub 2}({sup 1}{Sigma}{sub g}{sup +})) and to subsequent disintegration of the cluster. Formation of the excimer is induced by one of two outgoing electrons originating from the previous successful ionization inside the same cluster.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 127916
- Report Number(s):
- CONF-920376--
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 9 Vol. 37; ISSN 0003-0503; ISSN BAPSA6
- Country of Publication:
- United States
- Language:
- English
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