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Quantum chemical methods for studying photon and electron driven processes

研究光子和电子驱动过程的量子化学方法

基本信息

批准号：
1800171
负责人：
Spiridoula Matsika
金额：
$ 45万
依托单位：
Temple University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-15 至 2022-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1800171&HistoricalAwards=false
关键词：
Quantum chemical methods studying photon

项目摘要

Professor Spiridoula Matsika of Temple University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry Division to develop and apply theoretical methods to better understand electron-driven processes. Heat, light (photons), and electrons provide different routes to initiate chemical reactions. While heat- and photon-driven chemical processes are well studied, electron-driven processes are not well understood, even though electrons are ubiquitous in nature. Electrons are generated by radiation, and their collisions with atoms and molecules are essential in biology and chemistry, as well as in technology. Examples of electron-driven phenomena can be found in interstellar chemistry, radiation chemistry, environmental chemistry, stability of waste repositories, plasma processing of materials for microelectronic devices, and other applications. A major complication in electron-driven processes is that the states that are involved are metastable. Matsika and her research group develop computational and theoretical approaches to treat metastable states and their chemical reactivity. They specifically apply these methods to better understand DNA damage by radiation as well as formation of prebiotic molecules in interstellar medium. The research is expected to provide valuable insights into the understanding of important electron-driven phenomena in many areas of chemistry, specifically biological systems and formation of prebiotic molecules. This research is carried out by a research team involving collaboration of undergraduate and graduate students with postdoctoral associates. The involvement of high school students in research activities inspires students to be involved in science. This involvement has a very positive effect in their education and future career prospects.Conventional quantum chemical methods cannot be applied to study metastable states (or resonances), and several approaches have been developed to treat this problem. The Matsika group is developing appropriate methods that can treat metastable states and their chemical reactivity taking advantage of the knowledge of excited state reactivity. Specific goals of this work are to develop and test of efficient multireference methods for resonances. The complex absorbing potential approach is used in combination with multireference configuration interaction (MRCI) to obtain both the energies and lifetimes of these states. The performance of the complex absorbing potential method (CAP) is compared with that of orbital stabilization methods for medium sized molecules in combination with various electronic structure methods. Gradients and nonadiabatic couplings for CAP/MRCI are developed. These methods are used to explore complex potential energy surfaces and conical intersections between complex surfaces. The developed methods are used to study electron-driven processes related to radiation damage in nucleobases and the formation of organic molecules in the interstellar medium. The methodology is being implemented in publicly available computational software. Students with a range of backgrounds and levels of academic preparation contribute to this work.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.

天普大学的Spiridoula Matsika教授得到了化学系化学理论，模型和计算方法项目的支持，以开发和应用理论方法来更好地理解电子驱动的过程。热、光（光子）和电子提供不同的途径来引发化学反应。虽然热和光子驱动的化学过程得到了很好的研究，但电子驱动的过程还没有得到很好的理解，尽管电子在自然界中无处不在。电子是由辐射产生的，它们与原子和分子的碰撞在生物学和化学以及技术中都是必不可少的。电子驱动现象的例子可以在星际化学、辐射化学、环境化学、废物储存库的稳定性、微电子设备材料的等离子体处理和其他应用中找到。电子驱动过程的一个主要复杂性是所涉及的状态是亚稳态。Matsika和她的研究小组开发了计算和理论方法来处理亚稳态及其化学反应性。他们专门应用这些方法来更好地了解辐射对DNA的损伤以及星际介质中益生元分子的形成。这项研究有望为理解许多化学领域中重要的电子驱动现象提供有价值的见解，特别是生物系统和益生元分子的形成。这项研究是由一个研究小组进行的，涉及本科生和研究生与博士后合作。高中生参与研究活动，激发学生参与科学。这种参与对他们的教育和未来的职业前景有非常积极的影响。传统的量子化学方法不能应用于研究亚稳态（或共振），已经开发了几种方法来处理这个问题。 Matsika小组正在开发适当的方法，可以利用激发态反应性的知识来处理亚稳态及其化学反应性。这项工作的具体目标是开发和测试有效的多参考方法的共振。复吸收势方法与多参考组态相互作用（MRCI）相结合，以获得这些状态的能量和寿命。比较了复吸收势方法（CAP）与结合各种电子结构方法的中等分子轨道稳定方法的性能。发展了CAP/MRCI的绝热耦合和非绝热耦合。这些方法用于探索复杂的势能曲面和复杂曲面之间的圆锥相交。所开发的方法用于研究与核碱基辐射损伤和星际介质中有机分子形成有关的电子驱动过程。该方法正在公开可用的计算软件中实施。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。