Investigation of Interfacial and Bulk Dissociation of HBr, HCl, and HNO3 Using Density Functional Theory-Based Molecular Dynamics Simulations

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• 作者：Marcel D. Baer ; Douglas J. Tobias ; Christopher J. Mundy
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：December 18, 2014
• 年：2014
• 卷：118
• 期：50
• 页码：29412-29420
• 全文大小：417K
• ISSN：1932-7455

文摘

In this study, we calculate free-energy profiles for the dissociation of the strong acids XH (HBr, HCl, and HNO₃), specifically, for the deprotonation and subsequent formation of ion pairs, X^{鈥?/sup>路路路H₃O+, in the vicinity of the air鈥搘ater interface. We show that the free-energy profiles for the dissociation of HCl and HNO₃ are significantly different at the air鈥搘ater interface compared to in the bulk, and we predict that the undissociated, molecular form of these two acids is stable at the interface. For the strongest acid we consider, HBr the traditional picture of completely dissociated strong acids is preserved in the vicinity of the air鈥搘ater interface. Our results have implications for our understanding of the interfacial chemistry of acids, as well as the effects of acids on the surface tensions of aqueous solutions.}