Hydroxide anion at the air–water interface

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• 作者：Christopher J. Mundy ; I-Feng W. Kuo ; Mark E. Tuckerman ; Hee-Seung Lee ; Douglas J. Tobias
• 刊名：Chemical Physics Letters
• 出版年：2009
• 出版时间：19 October 2009
• 年：2009
• 卷：481
• 期：1-3
• 页码：2-8
• 全文大小：449 K

文摘

Whether aqueous interfaces are acidic or basic has implications for interfacial chemistry, but the question remains open. We employ first-principles molecular dynamics simulations to determine the intrinsic propensity of OH⁻ for the air–water interface and find that OH⁻ is stabilized by roughly k_BT at the interface vs. the bulk. We predict, therefore, that the surface population OH⁻ is slightly enhanced. Our simulations suggest that the solvation of OH⁻ at the interface is similar to that observed in small water clusters, and they reveal changes in the orientation of solvating water molecules that are consistent with surface-sensitive vibrational spectra.