Ultrafast Molecular Sciences

20世纪的分子科学是以理解微观世界的结构为基础的。这一点的重要性怎么说都不为过。识别分子和固体的形状导致了结构-功能关系，这产生了分子生物学、计算机芯片、塑料和药物设计。然而，自然并不是一成不变的：光合作用、视觉、太阳能转换等背后有许多快速的分子过程。在21世纪，我们必须超越结构，发展对自然过程的动态理解。这项建议就是针对这一目标的。具体地说，我们将使用新的超快电子和X射线技术，研究分子动力学的基本方面，以期制定简单的规则，在超快(飞秒)的时间尺度上，如何在这些过程中管理电子电荷和能量流动。超快分子科学基于高功率激光技术的革命性进步，现在允许从红外到软X射线区域产生超短脉冲。这项提议建立在CFI支持的主要基础设施之上，由NSERC支持的HQP进行研究计划。*高功率超短脉冲激光技术提供了许多新的机会，而不仅仅是产生IR或X射线脉冲。与这种光脉冲相关的电动力甚至可能比束缚物质本身的电力更强。这意味着研究人员可以使用激光场来排列或塑造分子。在这里，我们将使用我们的能力来排列分子。分子一般是随机取向的，因此我们对其动力学的研究有些模糊。就像强迫孩子们排队拍照一样，我们可以使用激光电力来排列分子，这样我们就可以更清楚地观察它们的动态过程。我们将开发在3D中排列分子的技术，使我们能够最大限度地利用我们的新型电子和X射线光谱仪。*随着超短激光场变得更加强大，新的物理过程就会出现。一种名为强场电离的过程导致了物理学的一个新分支--阿托秒科学，这本身就是加拿大的发明。这一领域产生了世界上最短的光脉冲，现在允许研究人员研究分子内最快的过程，即电子如何在分子和材料中运动。然而，到目前为止开发的模型和技术只适用于非常简单的系统，如原子。为了扩大范围，我们将研究如何将这些阿秒方法应用于更复杂的分子，这是进步的要求。*最后，我们使用超短脉冲开发新的显微镜形式，允许在不添加任何染料或着色剂的情况下对样品进行化学特定成像。从生物医学到材料科学，再到自然资源，这种新型的成像技术在各个领域都很重要。

Molecular sciences in the 20th century was based on understanding the structure of the microscopic world. It is hard to overstate how important this was. Discerning the shapes of molecules and solids led to structure-function relationships which engendered Molecular Biology, computer chips, plastics and drug design. Nature, however, is not static: there are many rapid molecular processes underlying photosynthesis, vision, solar energy conversion etc. In the 21st century, we must go beyond structure' and develop a dynamical understanding of nature's processes. This proposal is directed towards this goal. Specifically, using novel ultrafast electron and X-ray techniques, we will study fundamental aspects of molecular dynamics, with a view towards developing simple rules' which govern how, on ultrafast (femtosecond) time scales, electronic charge and energy flow during such processes. Ultrafast Molecular Sciences is based on revolutionary advances in high power laser technology, now permitting ultrashort pulse generation from the infrared to the soft X-ray regions. This proposal builds on CFI-supported major infrastructure, with NSERC-supported HQPs carrying out the research program.******High power ultrashort pulse laser technology offers many new opportunities beyond generating IR or X-ray pulses. The electric forces associated with such light pulses can be even stronger than the electric forces which bind matter itself. This means that researchers can align or shape molecules using laser fields. Here, we will use our ability align molecules. Molecules are generally randomly oriented and therefore our studies of their dynamics are somewhat blurred. Much like forcing children to line up for a group photograph, we can use laser electric forces to line molecules up so that we may observe their dynamical processes much more clearly. We will develop techniques for aligning molecules in 3D, allowing us to apply our novel electron and X-ray spectroscopies to them with maximal benefit.******As ultrashort laser fields get even stronger, new physical processes occur. One process, called strong field ionization, has led to a new branch of physics called Attosecond Science, itself a Canadian invention. This field has produced the world's shortest light pulses and now permits researchers to study the fastest processes within molecules namely, how electrons move within molecules and materials. However, the models and techniques developed thus far only apply to very simple systems such as atoms. In order to broaden the scope, we will study how these attosecond methods apply to more complex molecules, a requirement for advancement.******Finally, we use ultrashort pulses to develop new forms of microscopy which permit chemical-specific imaging of samples without adding any dyes or stains. This new type of imaging is important for fields ranging from biomedicine, to material science, to natural resources.**