Advanced Monte-Carlo simulation techniques for classical crystalline solids, including confined crystals

All chemicals form crystalline solids, so naturally the variety of crystals and crystal properties is immense. Much of the technology of our modern society is based on crystalline solids. For example, inorganic semi-conductor crystals have given us computers, the internet and just about every electronic device there is. Molecular crystal engineering will very likely be just as important in the future. There is currently great interest in polymer crystals for optical and electronic applications (LEDs, lasers, and solar cells for example), in molecular organic crystals for high-technology devices such as photocopiers and computer displays, in gas-hydrates (which are a form of ice with encapsulated gas) which could well be important for providing our future energy needs (it is thought that there is more methane in the worlds natural gas-hydrate fields than in its oil and gas fields) and for locking-away the resulting greenhouse gases that are thought to be responsible for global warming, in advanced porous materials (or special crystal 'frameworks') which could be important for future gas separation processes (allowing carbon dioxide to be separated from exhausts, for example), in biologically related crystals (pharmaceuticals and proteins, for example) that are used in medicines and to understand how the human body works, and so on.All these developments will depend on being able to understand why a particular crystalline solid exists in a particular form, and how its properties depend on factors such as its dimension, or geometry, the shape of its molecules, their interactions with other molecules, and how molecules assemble into larger building blocks.Modern computers and methods now allow scientists to model, or simulate, many important molecular systems quickly, efficiently and at low cost. This is particularly true when modelling extremely small, or nanoscale molecular systems (where the system's dimensions are not that much larger than its molecules), because experiments on this scale are very difficult, and therefore expensive, to setup up and analyse. For example, molecular simulation is used routinely to model fluids, especially those confined in nanoscale pores. However, current methods for simulating crystalline solids, particularly those within these pores, are not entirely satisfactory. At best they are unwieldy and in the case of nanoscale crystals they are often flawed. The aim of the work proposed here is to develop new and better methods for simulating molecular crystals, particularly nanoscale crystals. I expect the molecular simulation methods developed during this work will become the standard method for simulating crystals because they will be the most straightforward, robust and efficient methods available. So these methods could have a direct impact on our ability to simulate molecular crystals correctly and efficiently, and therefore provide a 'step-change' in the prospects for engineering these crystals in the future.