Experimental X-Ray Studies of Liquid Surfaces

TL;DR

This paper reviews how synchrotron x-ray techniques enable detailed atomic-level studies of liquid surfaces, revealing unique surface structures and phenomena in metals, alloys, and water.

Contribution

It demonstrates the application of advanced x-ray methods to measure and analyze the atomic-scale surface structure of liquids, including metals and alloys, which was previously impossible.

Findings

Surface structures differ from bulk properties.

Identification of atomic layering in metallic and dielectric liquids.

Observation of surface phenomena like Gibbs adsorption and nanoscale wetting.

Abstract

Over the past two decades synchrotron facilities dedicated to the generation of x-rays for study of atoms, molecules and condensed matter have proliferated all over the world. As a result of the special properties of x-rays produced by these machines, there has been an enormous growth in the experimental possibilities. In this work we will demonstrate how these special properties can be used to carry out hitherto impossible measurements of the Angstrom level structure of the free surfaces of liquids. We demonstrate that surface structure of liquids is often different from that of the bulk. A large part of this thesis is devoted to surface-induced atomic or molecular layering phenomenon in metallic and dielectric liquids. In Chapters 1 through 10 we describe surface features of high-surface tension metals (Ga, In, Hg, Sn), as well as alkali metals (K, KNa) and water. The second part of the thesis (Chapters 11 through 16) is devoted to surface of binary metallic alloys (GaIn, HgAu, KNa, BiIn and GaBi), investigating a wide range of surface phenomena such as Gibbs adsorption and the tetra-point nanoscale wetting.