EXCITED STATE DYNAMICS OF DNA BASE PAIRS

在这个由化学系实验物理化学项目资助的奖项中，加州大学圣巴巴拉分校的Mattanjah S. de Vries教授将与他的本科生、研究生和高中生研究人员一起，研究光化学，特别是孤立核碱基及其相互之间和与水的团簇的激发态动力学。在吸收紫外线后，DNA碱基可以通过非常迅速地将激发能扩散为热量来避免化学转化，这一过程称为内部转化，可以安全地转移到环境中。因此，短暂的激发态提供了光化学稳定性。这一过程强烈依赖于分子结构，并且在生物环境中核碱基发生的特定形式中非常普遍。这些短暂的状态很难通过实验来研究，因此这些过程的大多数证据仍然是间接的。该项目将与布拉格的Pavel Hobza教授合作，采用新的气相技术进行这些研究，他的团队将应用最新的计算建模技术进行分析。德弗里斯教授将让学生参与他的努力，并为湾区博物馆-学校在线科学学习合作实验室试点项目做出贡献。DNA对辐射的反应与人类健康有关，因为辐射损伤会影响遗传繁殖并导致癌症。DNA光化学对于我们理解地球上的生命是如何发展的也很重要，因为益生元化学可能发生在富氧大气形成之前，因此在比到达地球的更强烈的紫外线照射下。今天的表面。为了在分子水平上详细了解这种光化学，我们需要在孤立的核碱基和碱基对上进行研究，并将结果与量子化学模型进行比较。这种方法允许德弗里斯教授和他的合作者观察内在的分子特性，并了解这些特性如何塑造生物系统的整体行为。因此，这项研究将有助于对控制生命分子构建块的基本过程的最基本理解。这些主题与尖端的激光和计算技术相结合，非常适合本小组传统上从事的外展活动。这些活动包括指导本科生，K-12外展活动，参与湾区博物馆-学校在线科学学习合作实验室试点项目，以及与杰克逊州立大学（密西西比州一所历史悠久的黑人大学）的学生合作。

In this award, funded by the Experimental Physical Chemistry Program of the Division of Chemistry, Professor Mattanjah S. de Vries of the University of California Santa Barbara, together with his undergraduate, graduate and high school student researchers, will investigate the photochemistry and in particular the excited state dynamics of isolated nucleobases and their clusters with each other and with water. Following absorption of UV light, DNA bases can avoid chemical transformation by very rapidly diffusing the excitation energy to heat, in a process called internal conversion, which can safely be transferred to the environment. Thus a short lived excited state provides photochemical stability. This process strongly depends on molecular structure and is remarkably prevalent in the specific forms in which nucleobases occur in biological contexts. These short lived states have been difficult to study experimentally and therefore most evidence for these processes is still indirect. This project will employ novel gas phase techniques for these studies in collaboration with Professor Pavel Hobza in Prague, whose group will apply the newest computational modeling techniques for analysis. Professor de Vries will engage students in his efforts and contribute to the Bay Area Museum-School Online Science Learning Collaboratory Pilot Projec.How DNA responds to radiation is relevant to human health because radiation damage can affect genetic propagation and lead to cancer. DNA photochemistry is also important for our understanding of how life on earth developed, because prebiotic chemistry presumably occurred before formation of an oxygen rich atmosphere and thus under more energetic UV irradiation than what reaches the earth?s surface today. To understand this photochemistry in detail and at the molecular level we need to study it in isolated nucleobases and base pairs and compare the results with quantum chemical modeling. This approach allows Professor de Vries and his collaborators to observe intrinsic molecular properties and understand how those shape the bulk behavior of biological systems. Therefore, this research will contribute to the most basic understanding of fundamental processes that govern the molecular building blocks of life. These topics, in combination with cutting-edge laser and computational techniques, lend themselves extraordinary well to outreach activities, which this group traditionally undertakes. These activities include mentoring undergraduates, K-12 outreach activities, participation in the Bay Area Museum-School Online Science Learning Collaboratory Pilot Project, and collaboration with the students at Jackson State University, a historically black college in Mississippi.