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MS: Massenspektrometrie
MS III: HV III
MS III.1: Invited Talk
Thursday, April 5, 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.