Poster Number 163
See more from this Division: Topical Sessions
See more from this Session: Nano-Phases and Nano-Structures in Earth Environments (Posters)
Abstract:
We use molecular dynamics (MD) computer simulations to study complex structural and dynamical behavior of water molecules and ions at the surfaces of metal oxides and hydroxides, mica, talc, clays, and hydrous cement phases. MD simulations also demonstrate great potential in significantly improving our interpretation of the spectra of complex, low frequency vibrational, rotational and translational modes associated with interlayer and surface species in hydrous layered minerals, thus providing molecular scale quantitative insight into the structure and dynamics of these important limiting cases of nano-confined fluids.
The structure and composition of mineral substrates significantly affect the structure of the interfacial aqueous layer, the effective diffusion rates of surface species, their lifetimes, translational and librational dynamics. Interfacial water molecules and ions simultaneously participate in several dynamic processes characterized by wide ranges of time- and length- scales. The first molecular layer of water at all surfaces is always highly ordered and has reduced translational and orientational mobility. This ordering is not simply ice-like, but resembles the behavior of supercooled water or amorphous ice, although with significant substrate-specific variations. At some surfaces, water molecules can easily form strong donating and accepting hydrogen bonds, thus developing stable interfacial H-bonding networks. However, at many surfaces the formation of such networks is hindered by the unfavorable surface charge distribution.
See more from this Division: Topical Sessions
See more from this Session: Nano-Phases and Nano-Structures in Earth Environments (Posters)