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MO: Fachverband Molekülphysik

MO 3: Femtosekundenspektroskopie I

MO 3.3: Vortrag

Montag, 10. März 2008, 14:45–15:00, 3G

Ultrafast thermal melting of bulk ice — •Stanislav Pandelov, Marcus Schmeißer, Hristo Iglev, and Alfred Laubereau — Physik-Department E11, Technische Universität München, 85748 Garching, Germany

Melting of ice is the most common structural transition and can provides us information about the microstructure of water. The ice-water phase transition after an ultrafast temperature jump is studied in protonated and isotopically mixed ice using 2-color IR spectroscopy [1, 2]. For energy depositions beyond the limit of superheating of the solid phase (330 ± 10 K) [3] partial melting is observed. The process occurs in two steps: (i) ultrafast thermal bulk melting of the excited ice lattice within 5 ± 2 ps and (ii) secondary melting at the generated phase boundaries with a time constant of 33 pm 5 ps [3]. The latter process (interfacial melting) is found to consume energy amounts in agreement with the latent heat of melting and is accompanied by an accelerated temperature and pressure decrease of the residual ice component. This results support a thermally-driven melting mechanism starting with homogeneous nucleation in the bulk.

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