J. Phys. Colloques
Volume 41, Numéro C8, Août 1980Fourth International Conference on Liquid and Amorphous Metals
|Page(s)||C8-167 - C8-170|
J. Phys. Colloques 41 (1980) C8-167-C8-170
DYNAMICAL CONCENTRATION FLUCTUATIONS IN LIQUID Li4PbM. Soltwisch1, D. Quitmann1, H. Ruppersberg2 et J.B. Suck3
1 Institut für Atom- und Festkörperphysik, Freie Universität Berlin, R.F.A.
2 Institut für Werkstoffwissenschaften, Universität des Saarlandes, Saarbrücken, R.F.A.
3 Institut Laue-Langevin, Avenue des Martyrs, 38042 Grenoble Cedex, France.
A measurement of the quasielastic neutron scattering from liquid 7Li4Pb has been performed at a time of flight spectrometer (E0 = 4.1 meV, ƊE0 = 0.28 meV) for q(E=0) = 0.25... 2.5 A-1. Corrections for background, absorption, self shielding, and multiple scattering were applied and the spectra were reduced to cross sections by normalization to vanadium. Since the coherent scattering lengths average to zero, the intensity observed is essentially due to the concentration fluctuation structure factor Scc(q,E). Scc(q,E) shows a pronounced quasielastic peak around q ≈ 1.5 A-1. In the region of the peak, the energy width narrows down by about a factor of two (de Gennes narrowing). A fit in terms of a sum of Lorentzians is attempted which corresponds to an extrapolation of the description valid in the hydrodynamic limit. The self diffusion constant for Li is derived from the 7Li incoherent scattering and an interdiffusion constant from Scc(q,E).