Materials modelling in London.

■ ■ What are you currently working on? My team and I are working on a range of projects in materials modelling, covering different questions, from the understanding of hydrogen bonding in DNA, to the determination of accurate reference data for molecules on surfaces, to high-pressure materials. At the moment, we also have a project funded by the European Research Council aimed at understanding ice formation at the molecular scale, and the role that impurities play in this process. Ultraclean water is surprisingly difficult to freeze and can easily be supercooled to well below 0 °C. The reason that water typically freezes at 0 °C, the thermodynamic phasetransition temperature, is the presence of impurities acting as catalysts, which reduce the free-energy barrier of nucleation. At the moment, there is no theory able to predict which materials are good or bad at nucleating ice. We are working on using simulation techniques to address this by, for example, screening different types of materials as well as doing model studies on generic substrates. Developing this fundamental insight could in principle also allow us to control ice formation, and better understand cloud formation.