SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Mini-Symposium: Molecular scale investigations of liquid-vapor interfaces II
O 58.4: Vortrag
Mittwoch, 3. März 2021, 11:50–12:10, R1
Vibrational Dynamics of Interfacial Ice Ih and Liquid Water — •Prerna Sudera1, Jenée D. Cyran2, Malte Deiseroth1, Marc-Jan van Zadel1, Mischa Bonn1, and Ellen Backus3 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2Baylor University, Waco, Texas, USA — 3University of Vienna, Vienna, Austria
The dynamics of vibrational energy relaxation and dissipation at surfaces of aqueous systems is relevant for chemical conversion occurring at the surface of those systems: the energy flow pathways determine the likelihood of a reaction taking place on the surface. Subtle differences in energy dissipation mechanism can account for different photo-chemical activities of water and ice surfaces, relevant for atmospheric processes. We excite water and ice at 3100 and 3300 cm-1, the low- and high-frequency regions of the water stretch band, with femtosecond infrared excitation pulses of 150 cm-1 bandwidth and probe over the entire O-H stretch region with Sum Frequency Generation spectroscopy. Our results show extremely rapid spectral diffusion for both ice and water on sub-100 fs timescales, before vibrational relaxation and thermal redistribution of excess energy on several hundreds of fs timescales. The non-hydrogen bonded water molecules show relaxation dynamics on a picosecond timescale with ice being slower than water. By comparing the observed relaxation dynamics of water molecules at the surface of single-crystalline ice and the water-air interface, we discuss the potential implications of the results for chemical dynamics at the two surfaces.