研究・研究者
研究会・セミナー
| 演 題 | 「Ultrafast superheating and bulk melting of ice」 |
|---|---|
| 日 時 | 2007年10月15日(月) 10:00 |
| 講演者 | Prof. Alfred Laubereau (Physik Department, Techinische Universitaet Muenchen, Germany; Foreign Councilor of IMS) |
| 場 所 | 分子研 研究棟2階 201セミナー室 |
| 概 要 | 現在分子研の外国人顧問であるミュンヘン工科大のA. Laubereau教授が10月15日から17日に滞在されます。この機会に，先生の最近の研究成果について下記の通りセミナーをして頂けることになりました。 皆様のご来聴を歓迎致します。 We report on ultrafast temperature jump experiments of neat and isotopically mixed, hexagonal ice. 2-color infrared spectroscopy with tunable subpicosecond pulses is performed, using the OH or OD-stretching vibrations for rapid heating and sensitive probing of the local thermodynamic conditions of the sample. A thermalization time of a few picoseconds and isochoric temperature and pressure changes are demonstrated above the common melting point of ice /1/. Maximum superheating up to 330 +/- 10 K is measured /2/. Energy deposition beyond this limit leads to partial melting of the bulk (since the available energy is not sufficient for complete melting). Catastrophic melting within the thermalization time of 5 +/- 2 ps is observed, followed by secondary melting with a time constant of 33 +/- 5 ps /3/. The latter process is assigned to interfacial melting at the generated internal phase boundaries and consumes the stored thermal energy, as seen from the simultaneous temperature decrease of the the residual ice component. The melting process is also accompanied by a decay of the initial isochoric pressure jump of 30 MPa with the time constant of 35 +/- 10 ps, as expected from the volume decrease by ultrafast melting. /1/ H. Iglev et al, Nature 439 (2006) 183 /2/ M. Schmeisser et al, Chem. Phys. Lett. 42 (2007) 171 /3/ M. Schmeisser et al, J. Phys. Chem. B 111 (2007) 11271 |
| お問合せ先 | 岡本裕巳（光分子科学研究領域） |
