Identifying Energy Dispersal Pathways in Bare and Hydrated Nuclear Bases: A New Dimension in Nanosecond Electronic Spectroscopy

参与生物学的分子，例如我们身体中的分子，会受到能量吸收的影响，特别是来自光的能量。我们通过晒伤，皮肤老化和皮肤癌看到这一点，主要由紫外线辐射引起。当吸收的能量没有足够快地扩散时，这些效应就会发生，因此会局部破坏分子。事实上，DNA和其他生物分子非常善于失去能量，所以只有当我们暴露在大量的阳光下时才会发生损伤。保护我们自己的一种方法是使用含有特殊有机分子的防晒霜，这些分子可以有效地分散太阳的能量，使其不会到达皮肤。因此，了解能量如何通过分子传播是非常重要的：不仅是为了了解我们的分子是如何受损的，而且是为了设计新的分子，可以保护我们免受阳光的照射。在这项工作中，我们将研究分子中的能级，并确定能量通过分子传播的途径，无论是在孤立的情况下，还是在水分子存在的情况下，因为我们体内的分子通常被水包围着。然而，预计最强的效果将来自最初几个与分子相互作用的水分子，因为这些水分子将附着在最活跃的位点上（只有最初几个孩子能很好地看到冰淇淋货车，其余的只能在人群中瞥见！）。我们的实验将在精心控制的条件下进行，使我们能够详细了解正在发生的事情，并能够看到一次添加一个水分子的效果。我们将能够看到能量如何在分子中移动，以及水的加入如何影响能量的移动。为了理解实验，我们需要能够对系统进行建模，但目前这种模型并不可靠。因此，我们将开发新的建模工具，并根据我们的实验进行测试。由于实验是明确定义的，这意味着模型可以以公平的方式进行测试。一旦模型建立，它们就可以用来深入了解使它们在阳光下稳定的分子的属性，这将有助于了解皮肤损伤（老化，皮肤癌），并允许工业界设计新的防晒化学品。

Molecules involved in biology, such as in our bodies, are affected by the absorption of energy, particularly from light. We see this via sunburn, skin aging and via skin cancer, mainly caused by ultraviolet radiation. These effects occur as the energy absorbed is not spread out quickly enough, and so can damage molecules locally. In fact, DNA and other biological molecules are very good at losing energy so it is only when we expose ourselves to large amounts of sunlight that damage occurs. One way to protect ourselves is to use sun creams that contain special organic molecules that can spread out the Sun's energy efficiently so that it does not reach the skin. Hence knowledge of how energy spreads through molecules is very important: both to understand how our molecules get damaged, but also in designing new molecules that can protect us from sunlight.In this work we will look at the energy levels in molecules and identify the pathways by which energy spreads through molecules, both in isolation, but also in the presence of water molecules, since molecules in our bodies are typically surrounded by water. However, it is expected that the strongest effect will come from the first few water molecules interacting with the molecule, since these will attach to the most active sites (it is the first few children who get a good view of the ice cream van, the rest only catch glimpses through the crowd!).Our experiments will be carried out under carefully-controlled conditions, allowing us to understand in detail what is happening, and to have the ability of seeing the effect of adding water molecules one at a time. We shall be able to see how the energy can move through the molecule, and how this is affected by the addition of the water.To understand the experiments we need to be able to model the systems, but such models are currently not reliable. Hence we shall develop new modelling tools, and test them against our experiments. Since the experiments are well-defined, it means that the models can be tested in a fair manner. Once the models are established, then they can be used to gain insight into the attributes of the molecules which make them stable in sunlight, and this will help with understanding skin damage (aging, skin cancer) and allow new chemicals for sun protection to be designed by industry.