The Role of Non-covalent Interactions in the Excited State Dynamics of Heterocyclic Compounds.

在这个由化学系化学结构动力学和机理A(CSDM-A)计划资助的项目中，加州大学圣巴巴拉分校的德·弗里斯教授将研究杂环化合物对紫外线辐射的反应。这些化合物形成了DNA碱基和许多其他重要分子的基本结构，它们对光的反应在许多实际过程中发挥着作用。例如，紫外线吸收后的光化学是辐射诱导DNA损伤的基本步骤。紫外光选择可能在早期地球上的生命前化学中发挥了关键作用。这些相同的工艺也在各种现代材料中得到应用。这些专题与尖端激光和计算技术相结合，有助于开展以这项工作为基础的外联活动。本科生和研究生都将接受先进实验仪器的设计和建造、复杂的计算机模拟和基础研究方面的培训。这项工作将与HBCU下属的杰克逊州立大学的科学家合作进行。德弗里斯教授和他的小组成员将担任各种方案的导师，这些方案旨在扩大代表不足的团体的成员在STEM中的参与。紫外光辐射的精确效应主要取决于分子结构，而基本的光化学作用受与其他分子的相互作用的影响。加州大学伯克利分校德弗里斯教授的实验室将通过气相光谱学实验研究杂环化合物和包含它们的团簇的基本光性质，并与计算化学家合作，将结果与量子化学模型进行比较。这些实验将研究pi堆积和氢键如何影响杂环化合物的激发态势能格局，以及如何改变光化学结果。该项目将在皮秒和纳秒的时间域内研究这些分子系统，并使用高级量子计算对结果进行建模。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, funded by the Chemical Structure Dynamics and Mechanisms A (CSDM-A) program of the Chemistry Division, Professor de Vries at the University of California Santa Barbara will study how heterocyclic compounds respond to exposure to ultraviolet (UV) radiation. Such compounds form the basic structure of DNA bases as well as many other important molecules and their response to light plays a role in many practical processes. For example, the photochemistry following UV absorption constitutes a fundamental step in radiation-induced DNA damage. UV photo-selection may have played a key role in prebiotic chemistry on an early earth. These same processes also find applications in a variety of modern materials. These topics, in combination with cutting-edge laser and computational techniques, lend themselves to outreach activities that will be based on this work. Both undergraduate and graduate students will receive training in the design and construction of advanced experimental instrumentation, complex computer simulation, and conducting fundamental research. This work will be carried out in collaboration with scientists at Jackson State University, an HBCU. Professor De Vries and members of his group will serve as mentors in various programs aimed at broadening participation of members of underrepresented groups in STEM. The precise effects of UV radiation depend critically on molecular structure and the fundamental photochemistry is affected by interactions with other molecules. The laboratory of Professor de Vries at UCSB will study fundamental photoproperties of heterocyclic compounds and clusters containing them experimentally by gas phase spectroscopy and collaborate with computational chemists to compare the results with quantum chemical modeling. The experiments will investigate how pi-stacking and hydrogen bonding affect the excited state potential energy landscape of heterocyclic compounds and how that changes the photochemical outcomes. The project will study these molecular systems in the picosecond and nanosecond time domains and model the results with high level quantum computations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.