Atomic Simulations of Volatile Coverage on Silicate Surfaces

Abstract Understanding how surface processes shape exosphere formation on airless bodies is limited by how surface properties influence the ejection of volatiles such as Na. Recent studies show that retention and release are sensitive to surface binding energy (SBE), motivating the need for SBE values as a function of mineral type and surface coverage. Currently, Na SBE values are available only for silica at 0 or 1 monolayer (ML) coverage. Here, we present the first SBE distributions at intermediate coverages (0.1–0.75 ML) on silica, along with the first SBE distributions for Na adsorbed on albite and anorthite from 0 to 1 ML. Increasing coverage shifts SBE distributions to lower energies, with mean SBE decreasing even at 0.1 ML. Results demonstrate that SBE depends nonlinearly on coverage and surface composition. We incorporate findings into sputtering models to quantify their impact on yield and energy distributions, highlighting the importance of coverage‐dependent SBEs in exosphere modeling.