PNNL

Abstract

Here we use first-principles molecular dynamics simulations, in which the forces are obtained "on the fly" from electronic structure calculations based on density functional theory, to determine the intrinsic propensity of the hydroxide anion for the air-water interface. We find that the hydroxide anion is stabilized by about 0.5 kcal/mol at the air-water interface vs. in bulk water, and we predict, therefore, that the population of the ion is enhanced roughly twofold at the interface.