Exploring the Connections between the Nonlinear Spectroscopy and the Potential Energy Landscapes of Liquids

在一个由化学系化学理论、模型和计算方法项目资助的项目中，布朗大学的理查德·斯特拉特教授正在开发新的方法来理解液体中分子所表现出的复杂且看似不规则的运动模式。 近期目标是深入了解玻璃形成液体和液晶的行为。这两种材料都具有巨大的技术意义，因为它们与非晶材料的制造和实际显示器件有关。此外，这些方法具有潜在的应用，以跨越更广泛的化学问题的解决方案。 其基本思想是利用高性能计算的最新进展来绘制出最有利的分子途径。 结合斯特拉特教授和他的研究小组设计的分析方法，其他使用超快激光技术的科学小组可以寻找这些理想的运动模式。推动这一努力的引擎是，现在可以通过过冷和介晶液体等复杂系统的真实势能景观找到测地线（最有效）路线。 但是，随着发现这些途径可以通过计算查询来辨别分子机制，设计多维光谱实验来确定这些机制的可能性就来了。 斯特拉特小组将研究各种测地线定义的分子机制的特定非线性光谱特征，看看适当选择的光谱是否有助于解决目前围绕过冷脆性液体和液晶动力学的一些谜团。 这一努力的一个组成部分（及其更广泛的影响的一部分）将使用这个项目作为一个工具，暴露大学本科生面临的问题，在前线面向计算的研究。 很难高估美国拥有一个受过教育的公民的重要性，因为他们了解如何使用计算机模拟等21世纪的科学方法来解决具有挑战性的问题。 通过专注于该项目的精心挑选的部分，来自各种不同背景的本科生将能够获得对科学研究所提供的挑战和可能性的赞赏。

In a project funded by the Chemical Theory, Models, and Computational Methods program of the Chemistry Division, Professor Richard Stratt of Brown University is developing new ways of understanding the complex and seemingly erratic patterns of motion exhibited by molecules in liquids. The immediate goal is to gain insights into the behavior of glass-forming liquids, and liquid crystals. Both of these materials are of enormous technological significance because of their relevance to the manufacture of amorphous materials and to practical display devices. In addition, these methods have potential applications to span an even broader range of chemical problems in solutions. The basic idea is to take advantage of recent progress in using high-performance computation to map out the most favorable molecular pathways. In combination with analysis methods being devised by Professor Stratt and his research group, other scientific groups using ultrafast laser techniques can look for these desired patterns of motion.The engine driving this effort is that it is now possible to find the geodesic (most efficient) routes through realistic potential energy landscapes of such complex systems as supercooled and mesogenic liquids. But, with the discovery that these routes can be computationally interrogated to discern molecular mechanisms comes the possibility of designing multidimensional spectroscopy experiments to ascertain those mechanisms. The Stratt group will be investigating the specific nonlinear spectroscopic signatures of various kinds of geodesic-defined molecular mechanisms to see if properly chosen spectra can help resolve some of the current mysteries surrounding the dynamics of supercooled fragile liquids and liquid crystals. An integral part of this effort (and part of its broader impact) will be the use of this project as a vehicle for exposing college undergraduates to issues faced in frontline computationally-oriented research. It is hard to overestimate the importance of the United States having an educated citizenry with an appreciation of how such 21st-century scientific methods as computer simulation can be used to approach challenging problems. By focusing on carefully selected portions of the project, undergraduates from a wide variety of different background will be able to gain an appreciation of the challenges and possibilities provided by scientific research.