Examination of liquid metal surfaces through angular and energy measurements of inert gas collisions with liquid Ga, In, and Bi

Gas–liquid scattering experiments are used to measure the recoil directions and energies of neon, argon, and xenon atoms scattering from liquid gallium, indium, and bismuth. The angular and energy distributions vary systematically with the identity of the gas and liquid and with the incident gas energy and liquid temperature. We find that the gas atoms scatter into a narrower angular range from liquids with higher surface tension γ (γGa>γIn>γBi), while they transfer less energy to liquids of higher atomic mass (mBi>mIn>mGa). Comparisons of the angular distributions with scattering models suggest that lower surface tension liquids possess atomically rougher surfaces that redirect impinging atoms more broadly into space. The trend we observe linking broader angular distributions with lower energy transfer appears to be a microscopic manifestation of a general trend between decreasing surface tension and increasing atomic mass for main group metals such as Ga, In, and Bi.