Liquid surfaces – clean and in vacuo

Abstract

Modern surface science owes much to electron, ion and mass spectroscopy but these techniques have rarely been applied to liquid surfaces: the problem is that a liquid surface is not easily maintained in a vacuum. Lord Rayleigh knew that 'All ordinary water surfaces are sensibly contaminated': he used moving barriers and currents of air to sweep surface layers of grease and soap, and used liquid jets in the measurement of the tension of surfaces within 10-2 s of their formation, but he was unaware that 108 s is long enough at NTP for the deposition of a complete monolayer of the gas phase.