Hamburg 2001 – scientific programme

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DY: Dynamik und Statistische Physik

DY 16: Wachstumsprozesse und Grenzfl
ächeneigenschaften

DY 16.4: Talk

Monday, March 26, 2001, 17:15–17:30, S 5.5

Solidification of hydrogen clusters — •Riccardo Mazzarello and Bernhard Kramer — I.Institut für Theoretische Physik, Universität Hamburg Jungiustrasse 9, D-20355 Hamburg

According to some Authors superfluid properties may be present in small parahydrogen clusters; in such aggregates the principal anthagonist of superfluidity is solidification. We investigate under what conditions solidification either cannot occur at all, or would occur only in times much longer than the lifetime of the cluster. Due to surface melting effects the exterior layers of the cluster do not solidify. As far as the inner core is concerned, the solidification times depend strongly on the values of the parameters. Nucleation implies a barrier, which can be overcome either by thermal fluctuations (at relatively high temperatures) or by tunneling (at very low temperatures). Although a better knowledge of the physical properties of parahydrogen is required, we confirm that in both cases the nucleation times can be exceedingly long.