Full embedding QM/MM scheme for modeling excited state proton transfer processes

用于模拟激发态质子转移过程的全嵌入 QM/MM 方案

• 批准号: 1465154
• 负责人: Lyudmila Slipchenko
• 金额: $ 42.58万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1465154&HistoricalAwards=false
• 关键词: Full; embedding; QM; MM; scheme

Lyudmila V. Slipchenko of Purdue University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry Division to develop new computational and theoretical tools for describing the transfer of protons involving molecules in which the electrons have been excited, often by absorption of light. The systems to be studied are in solution or in other complex environments. The phenomenon known as excited state proton transfer (ESPT) is ubiquitous. It naturally occurs in photoactive proteins, which play many important roles in biology, and takes place between DNA strands as a pathway for dissipating excess UV radiation. In technology, ESPT is exploited in artificial photo-devices, fluorescent chemo-sensors, and for manipulating the acidity of local environment with light pulses. However, mechanistic understanding of ESPT pathways, which is essential for design of efficient photochemical cells or photoacids, remains incomplete. This research is expected to contribute to the understanding and eventual control of ESPT processes by elucidating the role of environment (solvent, electrolyte, protein matrix) in these events. This knowledge will benefit scientists and engineers designing new classes of photoacids, chemo-sensors and artificial photo-devices. The algorithms developed and validated in this project will be broadly distributed and serve for predictive studies of a variety of photo-induced processes in chemistry, biology, and materials. Slipchenko and her research group aim to characterize static and dynamic environment effects on complex photochemical and photophysical processes such as ESPT by (i) developing novel first-principles based methodology of QM/MM (Quantum Mechanics/Molecular Mechanics) type, (ii) validating and benchmarking this methodology relative to other established and emerging methods by creating a condensed-phase photochemistry database, and (iii) applying newly developed tools for investigating ESPT mechanisms in solvated photoacids and proteins such as GFP and PYP. The proposed method developments are based on polarizable quantum mechanics/molecular mechanics (QM/MM) approach for electronic excited states, in which the environment (the MM part) is described by the sophisticated Effective Fragment Potential (EFP) method. The proposed work enhances the accuracy and applicability of the QM/EFP methods by (i) developing a full embedding QM/EFP model in which all interactions between the quantum and classical systems are accounted for quantum-mechanically, (ii) extending this model to biological environments, and (iii) developing QM/EFP excited state molecular dynamics algorithms. The novelty of the proposed research is in creating a unique full embedding QM/MM model and applying it to excited state dynamics in various complex environments. The proposed research contributes to the research infrastructure byintegrating new computer codes in the open-source, freely available libefp library and in open-source PSI4, GAMESS and NWChem electronic structure packages and as open-source modules in Q-Chem and MOLCAS quantum chemistry software. The proposed condensed-phase photochemistry database, containing a variety of photoactive molecules in various environments, will contribute to quantum chemistry education in the community by providing benchmarks of newly developed and established methods for extended systems and by supplying online tutorials.

普渡大学的Lyudmila V. Slipchenko获得了化学系化学理论、模型和计算方法项目的奖励，她开发了新的计算和理论工具，用于描述电子被激发的分子（通常是通过吸收光）中的质子转移。要研究的系统是在溶液中或在其他复杂环境中。被称为激发态质子转移（ESPT）的现象是普遍存在的。它自然发生在光活性蛋白中，在生物学中起着许多重要作用，并在DNA链之间发生，作为消散过量紫外线辐射的途径。在技术上，ESPT被用于人造光器件、荧光化学传感器以及用光脉冲控制局部环境的酸度。然而，对于设计高效光化学电池或光酸至关重要的ESPT通路的机制理解仍然不完整。通过阐明环境（溶剂、电解质、蛋白质基质）在这些过程中的作用，本研究有望有助于理解和最终控制ESPT过程。这些知识将有助于科学家和工程师设计新型光酸、化学传感器和人造光器件。在这个项目中开发和验证的算法将广泛分布，并为化学、生物和材料中各种光诱导过程的预测研究服务。Slipchenko和她的研究小组旨在通过(i)开发基于QM/MM（量子力学/分子力学）类型的新颖第一性原理的方法来表征静态和动态环境对复杂光化学和光物理过程（如ESPT）的影响，（ii）通过创建一个冷凝相光化学数据库，相对于其他已建立和新兴的方法，验证并对该方法进行基准测试。（iii）应用新开发的工具来研究溶剂化光酸和蛋白质（如GFP和PYP）中的ESPT机制。提出的方法发展是基于电子激发态的极化量子力学/分子力学（QM/MM）方法，其中环境（MM部分）由复杂的有效碎片势（EFP）方法描述。提出的工作通过(i)建立一个完整的嵌入QM/EFP模型，其中量子系统和经典系统之间的所有相互作用都是量子力学的，（ii）将该模型扩展到生物环境，以及（iii）开发QM/EFP激发态分子动力学算法，提高了QM/EFP方法的准确性和适用性。该研究的新颖之处在于创建了一个独特的全嵌入QM/MM模型，并将其应用于各种复杂环境下的激发态动力学。该研究通过将新的计算机代码集成到开源的免费libfp库和开源的PSI4、GAMESS和NWChem电子结构包中，并作为Q-Chem和MOLCAS量子化学软件的开源模块，为研究基础设施做出了贡献。拟议的凝聚态光化学数据库包含各种环境下的各种光活性分子，将通过为扩展系统提供新开发和建立的方法的基准以及提供在线教程，为社区的量子化学教育做出贡献。