Regensburg 2002 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 11: Fluiddynamik
DY 11.6: Vortrag
Montag, 11. März 2002, 11:30–11:45, H3
Microscopic dynamics of liquid NaCl — •Franz Demmel1, Wolf-Christian Pilgrim2, and Shinya Hosokawa2 — 1ILL, 6, rue Jules Horowitz 38042, BP 156, Grenoble Cedex 9 — 2Universitaet Marburg, Physikalische Chemie, Hanns MerrweinStr, D-35032 Marburg
Liquid salts are important systems for the use in electrochemical processes and have recently received renewed interest due to their application in high temperature fuel cells. About 25 years ago, Hansen and McDonald carried out a pioneering MD-work on liquid alkali halides, the prototypes of ionic liquids. These simulations revealed the existence of propagating short wavelength charge fluctuations (optical phonons). With neutrons the interesting low momentum transfer range is difficult to access. We have used X-ray scattering to study the excitations particularly in the low momentum transfer range, where they should not interfere with acoustic type excitations. The experiment was performed at the ESRF/ID28 inelastic beamline. Molten NaCl was measured at a temperature of 1170 K enclosed in a thin sapphire cell. The spectra show clear indications (shoulders) for optical contributions at larger momentum transfer vectors. At the smallest k - vectors there is a weak evidence for an optic-like excitation.