Adsorption of Meteoritic Sugars on Forsterite Surfaces: A First-Principles Study

Abstract

Sugar-related organic molecules identified in carbonaceous meteorites provide key insight into the extraterrestrial inventory of prebiotic compounds. Here, density functional theory (DFT) calculations are used to investigate the adsorption of representative sugar acids and sugar alcohols from the Murchison meteorite on the forsterite (010) surface, a model silicate mineral relevant to planetary materials. The results show that adsorption occurs primarily through oxygen-containing functional groups, with both hydroxyl (−OH) and carboxylic (−COOH) groups forming stable Mg–O bonds with surface magnesium sites. Adsorption via the –COOH group is consistently stronger than via –OH due to the combined effect of Mg–O coordination and additional hydrogen bonding. Calculated adsorption energies indicate chemisorption and increase systematically with carbon chain length, reflecting enhanced stabilization for larger molecules. Structural and electronic analyses, including Mg–O bond distances, Bader charge distribution, and density of states, reveal charge redistribution and orbital hybridization at the adsorbate–surface interface. These findings support a plausible mechanism in which sugar molecules can be stabilized on silicate mineral surfaces, facilitating their preservation and delivery in meteoritic environments. The results highlight the potential role of mineral surfaces as both stabilizing substrates and reactive platforms in prebiotic chemical evolution.