Quantum Chemical Methods for Studying Photon and Electron Driven Processes

在化学系化学理论、模型和计算方法计划的支持下，坦普尔大学的Spiridoula Matsika教授正在开发和应用计算工具来研究化学反应和其他由光或电子引发的现象。热、光子(光)和电子为引发化学反应提供了不同的能源。虽然人们对由热和光引发的反应进行了很好的研究，但对电子诱导的反应却知之甚少，尽管它们在生物、化学和技术中发挥着至关重要的作用。Matsika教授和她的研究小组正在开发高效而准确的方法来描述由电子引发的过程。开发的方法将通过与合作者提供的实验光谱进行比较来进行测试，并将用于研究与生物损伤、天体化学和催化有关的反应。特别重要的是与癌症和癌症治疗相关的DNA成分的辐射损伤反应。这项工作将对研究生和本科生以及博士后研究员的教育产生更广泛的影响。马西卡博士还将努力加强来自代表性不足群体的学生对研究和科学的参与。这项研究计划将为博士后研究员以及研究生和本科生提供机会，以获得理论方法开发和量子力学方法应用于挑战性问题的培训。电子驱动过程的一个主要问题是，当电子与分子体系结合时形成的态通常是亚稳态，可以通过自动分离快速衰减，因此必须正确地将其视为共振。由于共振不是束缚态，传统的量子化学方法不能应用，需要修正来描述这些亚稳态的能量和寿命。为了在电子驱动过程的理论描述方面取得进展，Matsika小组将专注于以下目标：1)将发展与复数吸收势相结合的有效的多参考方法。2)这些方法将被用来探索复杂势能面和复杂曲面之间的圆锥交。在飞行中，将执行临时阴离子的动力学，并将计算光谱可观测值(如时间分辨光电子能谱)。3)这些方法将通过与实验小组合作进行基准测试。Matsika小组将专注于一系列应用，旨在更好地了解电子与生物、天体化学和催化相关分子的相互作用。特别是，该团队试图获得电子诱导的生物分子损伤的更完整的图景，特别是核碱基。开发的方法将在开源软件中实施。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Professor Spiridoula Matsika of Temple University is developing and applying computational tools to study chemical reactions and other phenomena initiated by light or electrons. Heat, photons (light), and electrons provide different energy sources to initiate chemical reactions. While reactions initiated by heat and light are well studied, electron-induced reactions are less well understood, even though they play a crucial role in biology, chemistry, and technology. Professor Matsika and her research group are developing efficient and accurate methods to describe processes initiated by electrons. The developed methods will be tested by comparisons with experimental spectra provided by collaborators, and they will be applied to study reactions related to biological damage, astrochemistry and catalysis. Of special importance will be reactions involved in radiation damage to components of DNA, related to cancer and cancer therapies. This work will have broader impacts in the education of graduate and undergraduate students as well as postdoctoral fellows. Dr. Matsika will also make efforts to enhance involvement of students from underrepresented groups in research and science. This research plan will give the opportunity to postdoctoral fellows, as well as graduate and undergraduate students to get training in theoretical methods development and in applications of quantum mechanical methods to challenging problems.A major problem with electron-driven processes is that the states formed when an electron is attached to a molecular system are often metastable and can decay fast via autodetachment, so one must treat them properly as resonances. Since resonances are not bound states, conventional quantum chemical methods cannot be applied, and modifications are needed to describe the energies and lifetimes of these metastable states. To make progress in the theoretical description of electron-driven processes the Matsika group will focus on the following objectives: 1) Efficient multireference methods combined with complex absorbing potentials will be developed. 2) These methods will be used to explore complex potential energy surfaces and conical intersections between complex surfaces. On the fly dynamics for temporary anions will be performed, and spectroscopic observables (such as time resolved photoelectron spectra) will be calculated. 3) The methods will be benchmarked by collaboration with experimental groups. The Matsika group will focus on a range of applications that aim at a better understanding of interactions of electrons with molecules relevant to biology, astrochemistry, and catalysis. Particularly, the team seeks to obtain a more complete picture of electron-induced damage to biomolecules, particularly nucleobases. The methodology developed will be implemented in open-source software.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.