THE STRUCTURE OF LIQUID METAL SURFACES: X-RAY REFLECTIVITY STUDIES⁺ P.S. Pershan¹, M. J. Regan1 , O. M. Magnussen^2,3, B. M. Ocko², M. Deutsch⁴, L. E. Berman⁵, ¹Division of Applied Sciences and Department of Physics, Harvard University, Cambridge, MA 02138, ²Department of Physics, Brookhaven National Laboratory, Upton, NY 11973, ³Current address, Abteilung Oberflaechenchemie und Katalyse University Ulm, Germany, ⁴Department of Physics, Bar-Ilan University, Ramat-Gan 52100, Israel, ⁵National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973

The strong Coulombic and quantum interactions between the charged electron and ion fluids that constitute liquid metals were long predicted by theory and simulation to give rise to atomic layering at the free surface. This important prediction of atomic layering was verified recently by our group's x-ray reflectivity measurements on liquid gallium and mercury; however, unexpected differences between the surface layering for the two elements leave open fundamental questions that are reinforced by more recent results on the temperature dependence of the atomic layering of liquid gallium. Other experimental results will be reported on the oxidation of the liquid gallium surface, and self-assembled monolayers on mercury surfaces. Finally, discrepancies between the measured surface profiles and those from current theory and simulations will be discussed.

⁺This work has been supported by grants from the U.S. Department of Energy, DE-FG02-88-ER45379 and the National Science Foundation, DMR-94-00396 and DMR-95-23440. Brookhaven National Laboratory is supported by DOE Contract No. DE-ACO2-76CH00016. MD acknowledges support by the Bar-Ilan Research Authority.