Excitation Dynamics in Nanoscale Systems: Atomistic Time-Domain Theory and Simulation

在这个由化学系的化学理论，模型和计算方法项目以及材料研究系的凝聚态物质和材料理论项目资助的项目中，南加州大学的Oleg Prezhdo教授正在开发新的化学理论和纳米材料超快动力学的计算机模拟。 这些纳米材料的电子和光学特性的模拟将有助于为太阳能转换，电子和成像的新设备的开发提供理论基础。 Prezhdo教授正在应用这些方法来研究两类材料。 第一种是混合钙钛矿，显示出创纪录的太阳能电池效率，第二种是二维材料，如石墨烯，可用于电子器件。 该项目还涉及课程开发方面，包括为广大受众设计新颖的教学工具，以及学生参与能源科学。Prezhdo教授正在研究新的模拟方法和算法的开发和测试，重点是凝聚相的量子特性（如退相干），多粒子和超交换过程以及非绝热转变。 这项研究为超快非平衡现象提供了更严格的处理方法。 他还致力于在时域密度泛函理论（TDDFT）中实施和测试非绝热分子动力学（NAMD）方法，目标是将NAMD的适用性扩展到新问题和更大的系统，其电子结构可以通过从头算和紧束缚DFT来描述。 这些系统包括新型过程（俄歇辅助电子转移和相关的多粒子现象）和纳米级材料。 最后，Preszhdo教授正在使用这些方法研究钙钛矿和二维材料中的激发动力学。

In this project funded by the Chemical Theory, Models and Computational Methods program in the Division of Chemistry and the Condensed Matter and Materials Theory program in the Division of Materials Research, Professor Oleg Prezhdo of the University of Southern California is developing new chemical theory and computer simulations of ultrafast dynamics in nanomaterials. These simulations of the electronic and optical properties of nanoscale materials will help to generate a theoretical basis for the development of novel devices for solar energy conversion, electronics and imaging. Professor Prezhdo is applying these methods to study two classes of materials. The first are hybrid perovskites that show record solar cell efficiencies, and the second are two-dimensional materials, such as graphene, which may be used in ultrathin electronic devices. The project also involves aspects of curriculum development, including the design of novel teaching tools for large audiences, and student involvement in energy sciences. Professor Prezhdo is studying the development and testing of new simulation approaches and algorithms with the focus on the quantum properties of condensed phases (such as decoherence), many-particle and super-exchange processes, and non-adiabatic transitions. This research is providing more rigorous treatments of ultrafast non-equilibrium phenomena. He is also working on the implementation and testing of the non-adiabatic molecular dynamics (NAMD) approaches within time-domain density functional theory (TDDFT) with the goal of extending the applicability of NAMD to new problems and larger systems whose electronic structure can be described by ab initio and tight binding DFT. These systems include new types of processes (Auger-assisted electron transfer and related many-particle phenomena) and nanoscale materials. Finally, Professor Preszhdo is using these methods to study the excitation dynamics in perovskites and two-dimensional materials.