Heidelberg 2015 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 20: Theory: Molecular Dynamics
MO 20.7: Vortrag
Donnerstag, 26. März 2015, 16:15–16:30, PH/SR106
Ultrafast Energy Transfer from Solvent to Solute induced by Sub-picosecond Highly Intense THz Pulses — •Pankaj Kr. Mishra1,2,3, Oriol Vendrell1,3, and Robin Santra1,2,3 — 1Center for Free-Electron Laser Science, DESY,Hamburg, Germany — 2Department of Physics, University of Hamburg, Germany — 3Center for Ultrafast Imaging,University of Hamburg, Germany
Liquid water is the single most important medium in which chemical and biological processes take place.The possibility to generate sub-ps and very intense THz pulses at free-electron lasers in full synchronization with the X-rays (XFEL) opens the possibility to time-resolved investigations of transient state of water and of molecular species dissolved in it. At low intensity, THz light couples to low energy collective modes of the liquid. Here, we investigated the response of liquid water to one and half cycle, 200 fs long THz pulses spectrally centered at about 100/cm (3 THz). The pulse with an intensity of about 5*10^12 W/cm^2 transfers the energy mostly to the translational and rotational modes of the water monomers in a small time-scale when the pulse is about to reach it's peak. The intramolecular vibrational energy also follows them after tens of fs during the pulse. Water reaches to a quasi-equilibrium state which is gas like very hot liquid. We also investigated the response of Phenol molecule to such THz pulse in vapor phase and in liquid water environment. Here the single phenol doesn't gain energy due to such pump pulse. But the phenol in liquid water gains significant amount of energy due to strong collision of highly mobile water molecule.