Ultrafast Molecular Sciences

世纪的分子科学是建立在对微观世界结构的理解基础上的。很难夸大这是多么重要。对分子和固体形状的识别导致了结构-功能关系，从而产生了分子生物学，计算机芯片，塑料和药物设计。然而，大自然并不是静止的：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，对自然过程进行动态的理解。本提案就是针对这一目标提出的。具体而言，使用新的超快电子和X射线技术，我们将研究分子动力学的基本方面，以期发展简单的规则，这些规则在超快（飞秒）时间尺度上如何管理，在这些过程中的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展，现在允许从红外到软X射线区域的超短脉冲产生。该提案建立在CFI支持的主要基础设施之上，由NSERC支持的HQP执行研究计划。高功率超短脉冲激光技术除了产生红外或X射线脉冲之外，还提供了许多新的机会。与这种光脉冲相关的电力甚至可以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排列或塑造分子。在这里，我们将利用我们的能力排列分子。分子通常是随机取向的，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合影一样，我们可以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力学过程。我们将开发3D分子排列技术，使我们能够将新的电子和X射线光谱应用于它们，并获得最大的收益。随着超短激光场变得更强，新的物理过程发生了。其中一个过程叫做强场电离，它导致了一个新的物理学分支，叫做阿秒科学，它本身就是加拿大人的发明。该领域已经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移动。然而，迄今为止开发的模型和技术仅适用于原子等非常简单的系统。为了扩大范围，我们将研究这些阿秒方法如何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形式的显微镜，允许化学特定的样品成像，而不添加任何染料或染色剂。这种新型成像技术对从生物医学到材料科学再到自然资源等领域都很重要。**

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.**