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.

Temple University的Spiridoula Matsika教授得到了化学理论，模型和计算方法计划的奖项，用于开发和应用理论方法，以更好地了解电子驱动的过程。热，光（光子）和电子提供不同的途径来引发化学反应。虽然对热和光子驱动的化学过程进行了充分的研究，但电子驱动的过程却尚不清楚，即使电子本质上是无处不在的。电子是通过辐射产生的，它们与原子和分子的碰撞在生物学和化学以及技术中至关重要。电子驱动现象的实例可以在星际化学，辐射化学，环境化学，废物存储库的稳定性，用于微电子设备的材料的血浆处理以及其他应用中找到。电子驱动过程的一个主要并发症是涉及的状态是可稳定的。 Matsika和她的研究小组开发了计算和理论方法来治疗可稳态及其化学反应性。他们专门应用这些方法来更好地理解辐射的DNA损伤，并在星际培养基中形成益生元分子。预计这项研究将提供有价值的见解，以了解许多化学领域，特别是生物系统和益生元分子的形成的重要电子驱动现象。这项研究是由一个研究团队进行的，涉及本科生和研究生与博士后同事的合作。高中生参与研究活动的参与激发了学生参与科学。这种参与对他们的教育和未来的职业前景具有非常积极的影响。规定的量子化学方法不能应用于研究可稳态（或共鸣），并且已经开发出了几种方法来治疗这一问题。 Matsika组正在开发适当的方法，可以利用激发状态反应性的知识来治疗可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互环共振方法。复杂的吸收潜在方法与多方面构型相互作用（MRCI）结合使用，以获得这些状态的能量和寿命。将复合物吸收势方法（CAP）的性能与中型分子的轨道稳定方法与各种电子结构方法结合使用。开发了CAP/MRCI的梯度和非绝热耦合。这些方法用于探索复杂的势能表面和复杂表面之间的圆锥形交集。所开发的方法用于研究与核碱基中辐射损伤和星际培养基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。具有一系列背景和学术准备水平的学生有助于这项工作。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。