Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 64: Gerhard Ertl Young Investigator Award
O 64.1: Vortrag
Donnerstag, 8. September 2022, 10:30–11:00, S051
Gold-colored metallic water solution — •Tillmann Buttersack1, Philip Mason2, Christian Schewe2, Ryan McMullen3, Florian Trinter1,4, Daniel Neumark5, Stephan Thürmer6, Robert Seidel7, Bernd Winter1, Stephen Bradforth3, and Pavel Jungwirth2 — 1Fritz-Haber-Institute, Berlin, GER — 2Czech Academy of Sciences, Prague, CZ — 3U Southern California, Los Angeles, USA — 4DESY, Hamburg, GER — 5UC Berkeley, USA — 6Kyoto U, JP — 7BESSY, Berlin, GER
Whereas tap water and common aqueous solutions conduct some electricity, pure water is an almost perfect insulator. The required pressures to transform water into a metallic state will not be achievable on Earth. Liquid Ammonia undergoes a gradual phase transition from a blue electrolyte solution to a bronze-colored metallic solution if the concentration of solvated alkali metal is enhanced. Water and alkali metals react vigorous, as the valence electrons of the alkali metal are transferred to the aqueous solution almost instantly, leading to a Coulomb explosion. Here, we demonstrate, that water from the gas phase adsorbs onto the surface of sodium-potassium alloy droplet leading to the formation of a thin shiny and golden layer. Characterization of the liquid with photoelectron and UV/Vis spectroscopy revealed a plasmon energy of 2.7 eV and signatures of liquid water. These observations are spectroscopic evidence for an aqueous solution with metallic properties. Its plasmon frequency is in the visible region of the spectrum and thus is the reason for the fascinating golden color.