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

• 批准号: 1465138
• 负责人: Spiridoula Matsika
• 金额: $ 48万
• 依托单位: Temple University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1465138&HistoricalAwards=false
• 关键词: Quantum; chemical; methods; studying; photon

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. Electrons are ubiquitous in nature. Collisions of electrons 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 in that the states that are involved are meta-stable since they can lose the electron via a process known as autodetachment. Matsika and her research group develop quantum mechanical approaches to treat metastable states and their behavior in electron-driven processes. They apply these methods to better understand DNA damage by radiation.. Low energy electrons can cause DNA strands to break and thus the interaction of low energy electrons with DNA is of major importance. This research will be carried out by a research team involving collaboration of undergraduate and graduate students with postdoctoral associates.Electron-driven processes have several similarities to photo-initiated processes, and progress made by the Matsika group and others in the latter field can be used to enhance the tools available in the former processes. In both photo-initiated and electron-driven phenomena electronically excited states are generated which are far from equilibrium and short lived. Nonadiabatic events are crucial and conical intersections are the rule rather than the exemption in both cases. Specific goals of this work are: 1) Development of efficient multireference configuration interaction (MRCI) methods for metastable states. The complex absorbing potential (CAP) approach is used in combination with MRCI to obtain both the energies and lifetimes of these states. A combination of conventional MRCI methods and CAP/MRCI are used to study potential energy surfaces, conical intersections, and nonadiabatic events related to resonances. 2) Theoretical studies of dissociative electron attachment (DEA) in nucleobases using the approaches developed in part (1). In order to address DEA in nucleobases the resonances are identified first, followed by explorations of the pathways leading to DEA and the experimentally observed products. The methodology developed will be implemented in publicly available computational software.

Temple University的Spiridoula Matsika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。电子本质上无处不在。电子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和其他应用中找到。电子驱动过程中的一个主要并发症是，涉及的状态是元稳定的，因为它们可以通过称为自动方案的过程丢失电子。 Matsika和她的研究小组开发了量子机械方法来治疗可稳态状态及其在电子驱动过程中的行为。 他们应用这些方法来更好地理解辐射的DNA损伤。低能电子会导致DNA链破裂，因此低能电子与DNA的相互作用至关重要。 这项研究将由一个研究团队进行，其中涉及本科生和研究生与博士后同事的合作。电子驱动的流程与照片发起的流程有几个相似之处，而Matsika Group和其他领域的其他过程则可以使用以前的工艺中可用的工具。在光发出和电子驱动的现象中，都产生了远离平衡和短暂寿命的现象。非绝热事件是至关重要的，在两种情况下，圆锥形的交集是规则，而不是豁免。这项工作的具体目标是：1）开发亚稳态状态的有效多次配置相互作用（MRCI）方法。复杂的吸收电位（CAP）方法与MRCI结合使用，以获得这些状态的能量和寿命。常规MRCI方法和CAP/MRCI的组合用于研究与共振有关的势能表面，锥形交叉点和非绝热事件。 2）使用第（1）部分中开发的方法对分离性电子附着（DEA）的理论研究。为了解决核碱中的DEA，首先确定共振，然后探索导致DEA和实验观察到的产物的途径。 开发的方法将在公开可用的计算软件中实施。