Regensburg 2004 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

TT: Tiefe Temperaturen

TT 33: Amorphe- und Tunnelsysteme, Gl
äser

TT 33.4: Vortrag

Freitag, 12. März 2004, 11:00–11:15, H19

Systematic Location and Description of Two Level Tunneling States in Simulated Lennard-Jones and Silicate Glasses. — •Jens Reinisch and Andreas Heuer — Institut für Physikalische Chemie and International Graduate School of Chemistry, Westfälische Wilhelms-Universität, Corrensstraße 30, 48149 Münster

Though the existence of Two Level Tunneling States (TLS) is widely accepted to explain low temperature anomalies in the sound absorption, heat capacity, thermal conductivity and other quantities, an exact description of their microscopic nature is still lacking. We performed computer simulations on a binary Lennard-Jones and a silicate system, using a newly developed algorithm to find TLS on a systematic basis. A detailed microscopic description of the Tunneling States in the simulated systems is thus available. Beyond structure we are also interested in general movement schemes for the participating particles. We found local density anomalies at the TLS, which are connected to the movement of the participating particles and we suggest that these anomalies are important for the TLS formation. For the LJ-system we will show strong evidence that only one particle is dominant in TLS, although several particles are moving. Furthermore, semi-quantitative estimations for the density of states of TLS are presented.