RUI: Time-independent excited state methods for computational screening of photoactive materials

西华盛顿大学的Tim Kowalczyk获得了化学系化学理论，模型和计算方法项目的奖项，以开发快速预测有机材料的可见光吸收，能量转换和发射能力的模拟。在这些材料中，光能重定向为电子流形成了新兴技术的基础，包括柔性太阳能电池，低毒性液流电池和用于治疗某些癌症的非侵入性光基疗法。该奖项支持的研究填补了现有方法的关键空白，使有机材料根据其光活性进行快速计算筛选。Kowalczyk指导了一个主要由学生研究人员组成的本科团队开发和应用这些模拟，以了解光吸收材料在隔离和复杂分子环境中的行为。这些快速筛选模拟与高精度建模相结合，揭示了专门的有机染料如何利用光中的能量产生活性氧物质的细节，这些活性氧物质在光动力癌症治疗中破坏病变组织。Kowalczyk和他的同事们正在通过开发、基准评估和在密度泛函紧束缚（DFTB）形式主义中应用与时间无关的激发态方法来寻求光敏材料筛选的快速模拟策略。这项研究旨在将新生的时间无关DFTB（TI-DFTB）方法转化为一种实用的，计算效率高的策略，用于光活性材料筛选以及凝聚相中的多尺度激发态模拟。该奖项开发的TI-DFTB分子动力学模拟能够在激发态势能表面上进行有效的构象采样，并对分子环境进行自洽的量子力学处理。从TI-DFTB激发态模拟中提取简单的化学描述符，以表征一系列有机发色团对单线态氧的光敏化作用。该奖项支持在一个主要的本科院校培训和指导不同群体的本科生和硕士水平的研究生。

Tim Kowalczyk of Western Washington University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop simulations that rapidly predict the visible-light absorption, energy conversion, and emission capabilities of organic materials. In these materials, the redirection of light energy into a flow of electrons forms the basis of emerging technologies including flexible solar cells, low-toxicity flow batteries, and noninvasive light-based therapies for the treatment of certain cancers. The research supported by this award fills a critical gap in existing methodology to enable fast computational screening of organic materials according to their photoactivity. Kowalczyk mentors a predominantly undergraduate team of student researchers in the development and application of these simulations to understand the behavior of light-absorbing materials both in isolation and in complex molecular environments. These rapid screening simulations are paired with high-accuracy modeling to uncover the details of how specialized organic dyes use the energy in light to produce the reactive oxygen species that destroy diseased tissue in photodynamic cancer therapy. Kowalczyk is linking demonstrations of simulations developed in this award to a program of undergraduate student-led energy literacy outreach in conjunction with WWU's Institute for Energy Studies.Kowalczyk and coworkers are pursuing rapid simulation strategies for photoactive materials screening through the development, benchmarking assessment, and application of time-independent excited state methods within the density-functional tight-binding (DFTB) formalism. This research seeks to transform the nascent time-independent DFTB (TI-DFTB) approach into a practical, computationally efficient strategy for photoactive materials screening as well as for multi-scale excited-state simulations in condensed phases. The TI-DFTB molecular dynamics simulations developed in this award enable efficient conformational sampling on excited-state potential energy surfaces with a self-consistent, quantum mechanical treatment of the molecular environment. Simple chemical descriptors are extracted from TI-DFTB excited-state simulations to characterize the photosensitization of singlet oxygen by a range of organic chromophores. This award supports the training and mentoring of a diverse group of undergraduate and masters-level research students at a primarily undergraduate institution.