Molecular Dynamics and Reactivity in Complex and Confined Fluids

在物质的三种状态中，液体是最难处理的。分子之间总是相互作用（不像气体），但不具有长程有序性，而且总是在运动（不像固体）。在过去，这使得科学家很难研究它们。因此，许多早期的定量研究集中在气相，这是化学和生物学的一个问题，其中大多数重要的过程实际上发生在液体中。幸运的是，在过去的几年里，我们对一些常见液体的理解有了巨大的进步。这首先是因为新的实验方法的发展，使人们有可能直接观察分子在液体状态下的运动（一个技术上的重大成就，因为这些动力学发生的时间小于百万分之一秒），其次是非常快速和有效的计算机程序使人们有可能精确地模拟液体动力学。然而，许多在化学和生物学中最重要的液体并不完全像通常研究的普通液体那样表现。例如，一些液体自发地形成大的（数百个分子）结构（活细胞是最重要的，最复杂的，例如）或改变它们的性质作为一些外部扰动的结果。这种被称为“复合流体”的液体非常重要，广泛存在于自然界和食品中（例如人造黄油），并具有重要的技术应用（液晶是另一个例子）。在这里描述的研究计划中，我们将扩展成功用于描述常见液体的方法，以首次研究这类重要的“复杂”流体的动力学。这将有助于我们理解材料和生命科学中的化学过程。

Of the three states of matter liquids are the most difficult to deal with. The molecules interact with one another all the time (unlike in gases) and yet possess no long range order, and move about all the time (unlike in solids). In the past this has made them hard for scientists to study. As a result much early quantitative research focussed on the gas phase, which is a problem for chemistry and biology, where most important processes actually happen in liquids. Fortunately our understanding of some common liquids has moved forward dramatically in the past few years. This is firstly because of the development of new experimental methods which make it possible to directly observe molecular motion in the liquid state (a technologically significant feat, since these dynamics occur in times of less than one million millionth of a second) and secondly very fast and efficient computer programs make it possible to model liquid dynamics accurately. However, many of the liquids that are most important in chemistry and biology do not behave exactly like the common liquids usually studied. For example some liquids spontaneously form large (hundreds of molecules) structures (the living cell being the most imporant, and most complex, example) or change their properties as a result of some external perturbation. Such liquids, called 'complex fluids', are of great importance, being widespread in nature and in foodstuffs (margarine for example) and having important technological applications (liquid crystals are another example). In the research program described here we will extend the methods used successfully to describe common liquids to investigate for the first time the dynamics of this important class of 'complex' fluids. This will contribute to our understanding of chemical processes in materials and life sciences.