Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 41: Glasses and Glass Transition II (jointly with DY, DF)
CPP 41.3: Vortrag
Donnerstag, 17. März 2011, 11:30–11:45, ZEU 114
Structural relaxation times in high-density amorphous ice (HDA) — •Philip H. Handle1, Markus Seidl1, Erwin Mayer2, and Thomas Loerting1 — 1Institute of Physical Chemistry, University of Innsbruck, Austria — 2Institute of General, Inorganic & Theoretical Chemistry, University of Innsbruck, Austria
Solid water (H2O) exists in a variety of different forms. Besides common hexagonal Ice (Ih) today 15 different crystalline and three different amorphous forms are known. It is under discussion whether the amorphous forms are glassy (related to liquid water [1]) or nano-crystalline (related to ice). In case of high-density amorphous ice (HDA) this question has been addressed in some studies [2-4], yet remains controversial. In our work we measured structural relaxation times of HDA at elevated pressures (0.1 and 0.2 GPa) and different temperatures (125-135 K) on the basis of differential scanning calorimetry (DSC) at 1 bar. Our data suggest that at 135 K the structural relaxation time is only slightly higher than 100s, i.e., HDA is on the borderline to the glass transition.
[1] Poole, P. H.; et al.; Nature 360, 324-328 (1992). [2] Tse, J. S.; et al.; Nature 400, 647-649 (1999). [3] Mishima, O.; J. Chem. Phys. 115, 4199-4202 (2001). [4] Andersson, O.; Phys. Rev. Lett. 95, 205503-205507 (2005).