Advancing the vibrational spectroscopy of silicate glasses

纵观历史，人们利用他们的材料知识来改善他们的生活方式。在当今时代，我们有非常先进的材料，用于许多应用，可能并不总是显而易见的用户。像电脑这样的普通物品需要先进的材料，而不仅仅是在防弹夹克这样的特殊应用中。为了开发更多更好的材料，我们需要改进研究材料的科学工具。材料最重要的特性之一是其内部原子的排列。例如，钻石（坚硬、透明、有价值）和石墨（柔软、黑色、铅笔用）都是由碳原子构成的，只是排列方式不同。研究材料原子结构的科学工具的不断进步促进了科学的进步。两个标准的工具是衍射和光谱学。衍射提供了一种直接测量物质中原子位置的方法，被广泛使用，但它需要x射线或中子，而这些都是昂贵的。光谱学涉及检测物质中原子状态的变化，并从这些变化中推断出原子位置的信息。光谱学可以使用使原子振动的红外光（即热）来完成，红外光可以使用激光廉价地提供。然而，这种振动光谱比衍射数据的解释要复杂得多。在研究玻璃时尤其如此，因为玻璃是一种原子排列不规律的材料。这一提议将改进振动光谱学作为研究玻璃原子结构的工具的使用，并将重点放在二氧化硅（砂）制成的玻璃上，这是最常见的玻璃。为了实现这些改进，我们将使用不同的工具来测量振动光谱（红外和拉曼光谱，以及非弹性中子散射）。这些结果将与通过模拟玻璃杯内原子位置（使用一种称为分子动力学的计算机建模技术）所做出的预测相结合。其他科学家以前也用这种方法处理过纯硅玻璃。我们的建议很重要，因为我们将研究含有金属原子的硅酸盐玻璃，而这些玻璃在日常生活中更为常见。例如，窗玻璃含有二氧化硅，也含有钠原子和钙原子，这些就是我们将要研究的玻璃类型。

Throughout history people have used their knowledge of materials to improve their way of life. In current times we have very advanced materials which are used for many applications that may not always be obvious to the user. Advanced materials are required for ordinary things like computers, and not just in special applications like bullet-proof jackets. To develop more and better materials we need improved scientific tools for studying materials. One of the most important properties of a material is the arrangement of atoms inside it. For example, both diamond (hard, clear and valuable) and graphite (soft, black and in pencils) are made of carbon atoms, but with different arrangements. The progress of science has been aided by a continuing advance in the scientific tools for studying the atomic structure of materials. Two of the standard tools for this are diffraction and spectroscopy . Diffraction provides a way of directly measuring the positions of atoms inside a material, and is very widely used, but it requires X-rays or neutrons which are expensive to supply. Spectroscopy involves detecting changes in the states of atoms within a material, and inferring information about the positions of atoms from these changes. Spectroscopy can be done using infrared light which makes atoms vibrate (i.e. heat), and infrared light can be cheaply supplied using lasers. However, this vibrational spectroscopy is much more complicated to interpret than diffraction data. This is especially the case when studying glasses, which are materials that don't have a regular arrangement of atoms.This proposal will improve the use of vibrational spectroscopy as a tool for investigating the atomic structure of glasses, and it focuses on glasses made of silica (sand), which are the most common kind. To make these improvements, we will use different tools to measure the vibrational spectra (infrared and Raman spectroscopy, and inelastic neutron scattering). The results will be combined with predictions made by simulating the positions of atoms within the glasses (using a computer modelling technique called molecular dynamics ). Other scientists have previously used this approach with pure silica glass. Our proposal is important because we will look at silicate glasses which also contain metal atoms, and these are far more common in everyday life. For example, window glass contains silica and also sodium and calcium atoms, and these are the type of glasses we will study.