# X-ray Study of the Liquid Potassium Surface: Structure and Capillary Wave Excitations

 Title: X-ray Study of the Liquid Potassium Surface: Structure and Capillary Wave Excitations Author: Shpyrko, Oleg; Huber, Patrick; Grigoriev, Alexei; Pershan, Peter S.; Ocko, Ben; Tostmann, Holger; Deutsch, Moshe Note: Order does not necessarily reflect citation order of authors. Citation: Shpyrko, Oleg, Patrick Huber, Alexei Grigoriev, Peter Pershan, Ben Ocko, Holger Tostmann, and Moshe Deutsch. 2003. X-ray study of the liquid potassium surface: Structure and capillary wave excitations. Physical Review B 67(115405). Access Status: Full text of the requested work is not available in DASH at this time (“dark deposit”). For more information on dark deposits, see our FAQ. Full Text & Related Files: Shpyrko_X-ray.pdf (139.8Kb; PDF) Abstract: We present x-ray reflectivity and diffuse scattering measurements from the liquid surface of pure potassium. They strongly suggest the existence of atomic layering at the free surface of a pure liquid metal with low surface tension. Prior to this study, layering was observed only for metals like Ga, In, and Hg, the surface tensions of which are five- to sevenfold higher than that of potassium, and hence closer to inducing an ideal “hard wall” boundary condition. The experimental result requires quantitative analysis of the contribution to the surface scattering from thermally excited capillary waves. Our measurements confirm the predicted form for the differential cross section for diffuse scattering, $$d \sigma/d\Omega \sim 1/q^{2-\eta}_{xy}$$ where $$\eta$$=$$k_{B}Tq^{2}_{z}$$/2$$\pi \gamma$$, over a range of $$\eta$$ and q$$_{xy}$$ that is larger than any previous measurement. The partial measure of the surface structure factor that we obtained agrees with computer simulations and theoretical predictions. Published Version: doi:10.1103/PhysRevB.67.115405 Other Sources: http://liquids.deas.harvard.edu/peter/2003.pdf/k_paper.pdf Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:10354433 Downloads of this work: