Simple Molecules Ain't So Simple

In this talk I will present results from two of this year's MPhys project students, on the atomistic simulation of liquid mixtures of water and methanol, using classical and ab initio molecular dynamics methods. After a brief, but necessary excursion into the problems of simulating water, I will present some results that confirm recent experimental suggestions that concentrated methanol-water mixtures exhibit 'microimmiscibility'. The water exists in pockets that are effectively hydrated in methanol, retaining local structural features similar to pure water. High pressure simulations indicate that these water clusters persist and coalesce.