Nagy, Gabor; Heinzinger, Karl; Spohr, Eckhard:

Modelling Water at Platinum Surfaces

In: Faraday Discussions, Jg. 94 (1992), S. 307-315
ISSN: 1359-6640
Zeitschriftenaufsatz / Fach: Chemie
Fakultät für Chemie
A series of molecular dynamics (MD) simulations has been performed to
investigate the water/platinum interface. Water laminae between Pt walls
and water monolayers on platinum were simulated under the influence of
an external electric field acting on the molecules. The system is thought to
be a realistic model for a water/metal interface. From the computer simulations
structural and dynamical properties of water are calculated and the
double layer is characterized. The dependence of the water structure,
especially the orientational structure, on the electrical field strength is investigated
as a function of distance from the surface. Electrostatic potential
profiles across the interface, work function changes, and dielectric properties
of water are calculated. The double-layer capacitance is estimated and found
to be almost independent of the external field. The dipolar relaxation
mechanisms in the adsorbed layer and in the bulk phase are discussed on
the basis of autocorrelation functions of the dipole moment vector calculated
for various field strengths. The spectral densities of librations and internal
vibrations are only slightly influenced by the application of an external
electric field.