X-ray absorption spectroscopy and microscopy of molecular materials: from fundamentals to applications

我的研究小组研究分子的x射线吸收光谱（XAS）的基本问题，并利用这些见解通过x射线光谱显微镜研究复杂的分子材料。******分子的XAS特征的形状是复杂的，并且在很大程度上逃脱了分析审查。这些形状（宽度、不对称等）的起源涉及到不同的展宽机制。然而，由于没有一个有效的模型来解释这些形状，分子XAS的这一方面经常被忽略。加拿大光源（CLS）改进的XAS实验，新的理论思想和高性能计算的结合使我们现在能够解决这些具有挑战性的问题。本课程将解释分子XAS中的线形和展宽，并使用这些现象来检查分子纳米材料的结构和秩序。XAS线形分析也将使我们能够研究有机电子器件中的聚集和不寻常的超稳定分子玻璃的结构起源。******通过使用互补同步加速器方法，该计划还将在x射线显微镜（即x射线光谱显微镜）中使用分子XAS来研究有序的分子纳米材料是如何形成的。模型系统的研究（正构烷烃在高对称表面的气相沉积）将用于发展对薄膜生长的一般见解。反过来，这些见解将用于开发在纳米尺度上模式和定义分子取向的一般方法。这些技术可用于制造依赖分子秩序的功能材料，如有机电子器件、超材料、波导和基于液晶的器件。对分子XAS的基本理解对于这些工作至关重要。******本研究计划扩展了XAS和x射线光谱显微镜在分子材料结构和秩序研究中的应用。它将提供对超稳定分子玻璃的更好理解，以及制造和定向有机纳米材料的新方法。大部分工作将在加拿大光源（CLS; Saskatoon， SK）进行，并与CLS软x射线光谱显微镜光束线的仪器和技术发展密切相关。**

My research group studies basic questions in the X-ray absorption spectroscopy (XAS) of molecules and uses these insights to study complex molecular materials by X-ray spectromicroscopy.******The shape of features in the XAS of molecules are complex and have largely escaped analytical scrutiny. Various broadening mechanisms are implicated as the origin of these shapes (width, asymmetry, etc). However, without an effective model to interpret these shapes, this aspect of molecular XAS is often ignored. The combination of improved XAS experiments at the Canadian Light Source (CLS), new theoretical ideas and high performance computing allows us now to address these challenging questions. This program will explain line shapes and broadening in molecular XAS and use these phenomena to examine structure and order in molecular nanomaterials. XAS line shape analysis will also allow us to study aggregation in organic electronic devices and the structural origin of unusual ultrastable molecular glasses.******Through the use of complementary synchrotron methods, this program will also use molecular XAS in an X-ray Microscope (that is, X-ray spectromicroscopy) to study how ordered molecular nanomaterials are formed. Study of model systems (vapour deposition of n-alkanes on high symmetry surfaces) will be used to develop general insights into thin film growth. In turn, these insights will be used to develop general methods to pattern and define molecular orientation at the nanoscale. Such technologies can be used to create functional materials that rely on molecular order, such as organic electronic devices, metamaterials, waveguides and liquid crystal-based devices. Fundamental understandings of molecular XAS are essential for these efforts.******This research program extends both XAS and X-ray spectromicroscopy in the study of structure and order in molecular materials. It will provide improved understandings of ultrastable molecular glasses and new methods to make and pattern oriented organic nanomaterials. Much of this work will be performed at the Canadian Light Source (CLS; Saskatoon, SK) and is tied closely to instrumentation and technology developments on the CLS soft X-ray spectromicroscopy beamline.  **