Collaborative Research: Multireference Studies of Organic Polyradicals, Radical Reactions and Graphene Nanoribbons

里士满大学的Carol教区和德克萨斯理工大学的Hans Lischka获得了化学理论，模型和计算方法计划的奖励，以进行对理解反应机制，热解和替代燃料，抗癌抗生素和石墨烯纳米器件的燃烧重要的二，四和多自由基分子的结构，反应性和激发态的理论研究。对多自由基的适当物理特征的基本了解对于多参考（MR）电子结构理论的进一步发展以及理解和控制涉及这些开壳层中间体的化学现象至关重要。本提案侧重于利用MR方法（MR-CI、MR-AQCC、CASPT 2）进行研究1。）模型系统，例如o-、m-和p-苯炔的几何形状和激发态，2.）在沥青质杂芳族化合物的热解中发现的双自由基中间体，3.）产生可用作抗癌抗生素的双自由基中间体的新颖电环化反应，4.）涉及四自由基的反应和通过键耦合在自由基电子相互作用中的作用，5.）石墨烯中的双自由基和多自由基缺陷，并将这些MR方法与DFT结果和6.）为哥伦布软件包开发输入和分析工具，以促进包括本科生在内的化学界使用这些高度相关的MR方法。适当地表征开壳聚自由基物种和相应的新型环化反应的研究的能力，为推进MR理论化学，机械有机化学，材料设计和药物优化领域提供了重要的希望。该提案描述了几个精心构思的理论实验，旨在由本科研究人员，研究生和博士后或博士后研究员进行。这将创建一个科学家社区，专注于使用最先进的电子结构方法对有趣的多自由基物种进行适当表征。各级学生将学习计算量子力学，光谱学和方法开发的细节。

Carol Parish at the University of Richmond and Hans Lischka at Texas Tech University are supported by an award from the Chemical Theory, Models and Computational methods program to perform theoretical investigations of the structures, reactivities and excited states of di-, tetra- and poly-radical molecules important to understanding reaction mechanisms, pyrolysis and combustion of alternative fuels, anticancer antibiotics and graphene nanodevices. A fundamental understanding of the proper physical characterization of polyradicals is critically important for the further development of multireference (MR) electronic structure theory as well as understanding and controlling chemical phenomenon involving these open-shell intermediates. This proposal focuses on utilizing MR methods (MR-CI, MR-AQCC, CASPT2) to study 1.) model systems such as the geometries and excites states of o-, m- and p-benzyne, 2.) diradical intermediates found in the pyrolyis of asphaltene heteroaromatic compounds, 3.) novel electrocyclization reactions producing diradical intermediates that may function as anticancer antibiotics, 4.) reactions involving tetraradicals and the role that through-bond coupling plays in radical electron interaction, 5.) diradical and multiradical defects in graphene and to benchmark these MR methods against DFT results and 6.) developing input and analysis tools for the COLUMBUS package to facilitate the use of these highly correlated MR methods by the chemical community including undergraduate students. The ability to characterize properly open-shell polyradical species and the corresponding investigation of novel cyclization reactions holds significant promise for advancing the fields of MR theoretical chemistry, mechanistic organic chemistry, materials design and drug optimization. The proposal delineates several carefully conceived theoretical experiments designed to be performed by undergraduate researchers, graduate students and post-baccalaureate or post-doctoral fellows. This will create a community of scientists focusing on the proper characterization of interesting polyradical species using state-of-the-art electronic structure methods. Students at all levels will learn the details of computational quantum mechanics, spectroscopy and methods development.