Title: Nano-confined Water from Simulations.
When: Wednesday, December 21, 2016, at 12:00.
Place: Sala de Grados, Módulo 8, Facultad de Ciencias, Universidad Autónoma de Madrid.
Speaker: Emilio Artacho, Department of Physics, The Cavendish Laboratory, University of Cambridge, UK.
In addition to enormously important for life and in other areas of science, water is an extraordinarily intriguing liquid, displaying a substantial number of anomalies in its macroscopic behaviour, which stem from the peculiar dynamics of its molecules at the microscopic scale. Water confined to nanometre dimensions is also of great interest for the life sciences (the water separating large molecules or organelles in a living cell can be reduced to manometric thin layers) and other contexts. In such conditions, the water behaviour is affected by the confining medium. Some time ago the question was asked of what would be the intrinsic tendencies of nano confined water, how would it like to behave if confined but if it were otherwise free. This is a very difficult question to pose to experiments, but it can be addressed with simulations: take a realistic model of water, and confine it with the most featureless confining potential. We have used both first-principles and empirical simulation to describe water for the purpose. First principles could be used for ice phases and for liquids away from freezing. Empirical potentials were validated by the simulations and allowed determining the phase diagram. A perfectly flat confining potential for two-dimensional water already offered interesting physics for the explored densities and temperatures (see phase diagram). Subsequently, we also allowed for controllable texture of the confining surfaces. This work is part of the PhD work of Jon Zubeltzu, also in collaboration with F. Corsetti and M. V. Fernandez-Serra.