Regensburg 2004 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Chemische Physik und Polymerphysik
CPP 4: Dynamics of Molecular Systems
CPP 4.4: Vortrag
Montag, 8. März 2004, 12:00–12:15, H 38
Local Modes in liquid Deuterium Fluoride — •Demmel Franz1, Gerhard Heusel2, Isabella Waldner2, Markus Kreitmeir2, and Helmut Bertagnolli2 — 1ILL, 38042 Grenoble, France — 2Universitaet Stuttgart, Physikalische Chemie, Stuttgart
Hydrogen bonded liquids are certainly one of the most complex, but also one of the most important liquids. Structure and dynamics is strongly determined by the hydrogen bonds. Water, the most prominent model system, shows a 3D network of bonds and has been studied for a long time. In contrast to water liquid hydrogen fluoride is connected in one-dimensional hydrogen bonded chains. A MD simulation of liquid HF has predicted an acoustic-like mode and a further optic-like mode in the spectra of the longitudinal current correlation functions [1]. For the interpretation of the optic mode a collective movement of HF molecules against themselves was suggested. We performed an inelastic neutron scattering experiment at the ILL, Grenoble, on liquid deuterium fluoride at two temperatures. The corrected spectra show evidences for an optic mode in a certain region of momentum transfer vectors as predicted by the MD simulation. These indications weaken or even vanish at the higher temperature near the triple point.
[1] D. Bertolini, G. Sutmann, A. Tani, R. Vallauri, PRL 81, (1998) 2080