Dresden 2011 – wissenschaftliches Programm

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MS: Fachverband Massenspektrometrie

MS 9: Ion Trap and FT-ICR-MS, Molecules, Clusters and Reactions

MS 9.1: Hauptvortrag

Freitag, 18. März 2011, 10:30–11:00, GÖR 229

Power-law decays of excited aluminum cluster anions and their blackbody radiation dependence — •Michael Froese, Felix Berg, Klaus Blaum, Michael Lange, Felix Laux, Sebastian Menk, Robert von Hahn, and Andreas Wolf — Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg

The decay of highly excited aluminum cluster anions has been investigated in the Cryogenic Trap for Fast ion beams (CTF). This electrostatic ion beam trap (EIBT) can be cooled with liquid helium and has demonstrated residual gas densities of 2000 particles/cm³. A power-law is found to accurately reproduce the time dependence of the observed decay rates at early times, although the exponents significantly differ from the typically observed 1/t decay in other small metal clusters and bio-molecules. Quenching of the power-law decay was also observed at later times. A strong dependence of both the power-law exponent and the quenching time on the ambient temperature was observed when decays in the trap at room-temperature and cryogenic temperatures were compared. The effect of blackbody radiation on the 1/t-type decay will be discussed based on these new observations.