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MS: Massenspektrometrie

MS III: HV III

MS III.1: Hauptvortrag

Donnerstag, 5. April 2001, 15:45–16:15, EB 202

Model-free determination of dissociation energies from sequential decays — •Lutz Schweikhard¹, Klavs Hansen², Alexander Herlert¹, and Manuel Vogel¹ — ¹Inst. f. Physik, Johannes Gutenberg-Universit ä t, D-55099 Mainz, Germany — ²Department of Physics, University of Jyväskylä, FIN-40500 Jyv ä skyl ä, Finland

A method is presented which allows a model-independent determination of the dissociation energy of polyatomic systems. The new technique makes use of the observation of sequential decays (A to B to C). The second decay serves as an uncalibrated thermometer of the fragment after the first decay. By comparison of the sequential decay with the single-step decay of this first fragment (B to C) the systematic uncertainties of model-dependent detailed descriptions of the decay processes can be avoided. The method is applied to gold clusters of various sizes where traditional approaches fail to produce accurate values for the dissociation energies. Thus the precision is increased from the ten-percent to the percent level. In addition, the new technique is not restricted to metal cluster research but is universal in the sense that it is is applicable to polyatomic systems which show an energy-characteristic sequential decay.