Dresden 2003 – wissenschaftliches Programm

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SYEC: Materials under extreme conditions

SYEC 2: Extreme Conditions II

SYEC 2.1: Hauptvortrag

Mittwoch, 26. März 2003, 16:00–16:30, HSZ/01

Neutron scattering under extreme P/T conditions — •Stefan Klotz — Physique des Milieux Condensés, Université P&M Curie, B77, 4 Place Jussieu, 75252 Paris, France

This talk will first give a brief overview of new experimental possibilities for high pressure neutron scattering up to 25 GPa and in the temperature range 80-2000 K. In the second part I will focus on very recent results on the structure and the transformations of amorphous ices at low temperatures, obtained by neutron diffraction at the ISIS facility. The structural pressure dependence of high density amorphous ice (HDA) to 2.2 GPa will be presented [1], and the relation of HDA to the recently discovered ’very high density amorphous’ form (VHDA) will be discussed. The first in-situ diffraction data of the pressure induced transformation of LDA (low density amorphous ice) to HDA will be shown [2]; the impact of these results on the ongoing water debate will be outlined.

[1] S. Klotz et al., Phys. Rev. Lett. 89, 285502 (2002).

[2] S. Klotz et al., Science, under review.