ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
The metastable fragmentation of the cluster ions (C4H10)nC4H+q (q=7 to 10) produced by the electron impact ionization of a neutral n-butane cluster beam has been studied with a double focusing sector field mass spectrometer. For q〉7, the usual statistical single-monomer evaporation is the only observable metastable fragmentation channel. Surprisingly, the (C4H10)nC4H+7 cluster ions were found to exhibit a more complex metastable decay pattern, involving not only the single-monomer evaporation, but also two additional fragmentation channels leading to evaporation of 2 to 4 and 4 to 7 (C4H10) monomers, respectively. After studying the dependence of the parent and the fragment ion currents on the electron energy, we concluded that the C4H+7 ionic chromophore of the (C4H10)nC4H+7 cluster ion is produced after internal H− transfer between n-C4H10 and some primary fragment ion (e.g., C2H+5, C2H+3, C3H+3, CH+3, C3H+4 ) of n-butane within the cluster. A mechanism based on the energy storage in metastable isomers of the C4H+7 chromophore ion is suggested to explain the unusual metastable fragmentation pattern of (C4H10)nC4H+7 cluster ions.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.462729
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