Computer simulation of the water/platinum interface

In: The journal of physical chemistry, Jg. 93 (1989) ; Nr. 16, S. 6171–6180
ISSN: 1943-3018, 0022-3654, 0092-7023
Zeitschriftenaufsatz / Fach: Chemie
Fakultät für Chemie
A molecular model for the water/platinum interface has been devised. It includes the surface corrugation of the metal and
orientationally anisotropic water-metal interactions obtained from quantum chemical cluster calculations. Barriers for the
surface diffusion and for the reorientation of a single water molecule on the quadratic (100) face of the face-centered-cubic
platinum crystal are discussed. The flexible BoppJancs6-Heinzinger water model describes the water-water interactions,
and the platinum-platinum interactions are described by a single force constant. Molecular dynamics simulations of a water
lamina confined by (100) platinum surfaces have been performed using these interaction potentials. The structure is discussed
on the basis of one-particle density profiles and solvent pair correlation functions. The surface-induced structural inhomogeneity
ranges up to distances of IO A. In the center of the lamina water properties are bulklike. Hydrogen bonding in the vicinity
of the interface is only slightly reduced relative to the bulk. The orientational structure of water is strongly influenced by
water-water interactions and is considerably different from the preferential orientation according to the water-platinum
interaction potential. It leads to a dipolar potential drop across the interface of 1.1 V.