Synchrotron and spectroscopic studies of glasses and melts

火山的物理和化学行为在很大程度上取决于火山下面的熔融物质或岩浆的性质。岩浆是硅酸盐熔体、晶体和溶解气体的混合物。熔体相在火成过程中起着重要的作用，因为熔体的结构影响流变学和扩散等性质。然而，直接原位研究熔体在技术上是困难的，研究淬火的熔体或玻璃更容易。自30年代以来，对熔体及其淬火玻璃结构的地质研究一直在进行，并且仍然如此，美国，日本，英国，法国和德国的大型研究小组积极开展这一领域的研究。通常，制备简单的熔体组合物并淬火成玻璃。所生产的玻璃具有与相应熔体非常相似的性质。然后，这些玻璃被复杂的仪器探测，光谱数据的分析提供了解释玻璃的物种形成、结构和配位的关键信息。通过确定组成如何影响合成玻璃的结构特性，可以建立一个基础，在此基础上开发更复杂的自然系统的结构模型。在这里，我建议研究的组成的影响1）的元素，如O，B，Al，Fe和Ti的配位，2）的影响，不同的碱金属（Li，Na，K，Rb的扩展的玻璃结构，3）是否Al在熔体中形成三团簇，和4）使用合成玻璃宿主核废料产品的适用性。这些项目涉及地质玻璃/熔体研究中当前感兴趣的明确界定的具体领域。研究的很大一部分将在加拿大光源（CLS）进行，这是最近在萨斯卡通开放的国家同步辐射设施。我对将采用的仪器和技术有着丰富的经验，并在其应用于玻璃/熔体研究方面享有国际声誉。此外，一些拟议的研究是与IPG（巴黎）和IMPMC（巴黎）的同事合作，并将利用加拿大以外的同步加速器设施。

The physical and chemical behaviour of volcanoes depends to a great extend on the properties of the molten material or magma beneath the volcano. Magmas are mixtures of silicate melt, crystals and dissolved gases. The melt phase plays an important role in igneous processes because the structure of the melt influences properties such as rheology and diffusion. However, direct in situ studies of melts are technically difficult and it is easier to study the quenched melt or glass. Geological research in to the structure of melts and their quenched glass has been ongoing since the 30s and remains so, with large research groups in the USA, Japan, England, France and Germany actively pursuing research in this area. In general, simple melt compositions are prepared and quenched to glass. The glasses produced have properties closely analogous to the corresponding melt. These glasses are then probed by sophisticated instrumentation and analysis of the spectroscopic data provides key information with which to interpret the speciation, structure and coordination of the glasses. By establishing how composition affects the structural properties of the synthetic glasses it is possible to establish a basis upon which to develop structural models of more complex natural systems. Here I propose to study the influence of composition on 1) the coordination of elements such as O, B, Al, Fe and Ti, 2) the influence of different alkalis (Li, Na, K, Rb) on the extended glass structure, 3) whether or not Al forms triclusters in melts and, 4) the suitability of using synthetic glasses to host nuclear waste products. These projects address specific well-defined areas of current interest in geological glass/melt research. A significant portion of the research will be carried out at the Canadian Light Source (CLS), the recently opened national synchrotron radiation facility in Saskatoon. I have extensive experience with the instrumentation and techniques that will be employed and have developed an international reputation in their application to glass/melt research. In addition, some of the proposed research is collaborative with colleagues at IPG (Paris) and IMPMC (Paris) and will utilise synchrotron facilities outside of Canada.