Developing and Applying Nonadiabatic Dynamics Methods for Nanoscale and Periodic Systems
出版項
2021
說明
1 online resource (266 pages)
文字
text
無媒介
computer
成冊
online resource
附註
Source: Dissertations Abstracts International, Volume: 83-01, Section: B
Advisor: Akimov, Alexey
Thesis (Ph.D.)--State University of New York at Buffalo, 2021
Includes bibliographical references
The need for accurate simulations of excited-state processes in systems pertinent to photovoltaic applications is becoming critical for those wishing to design high performance solar energy materials. This thesis presents the current state-of-the-art of such simulations and details key advancements made to them by my research in the Akimov group. The thesis begins by introducing the need for efficient solar energy materials and discusses how nonadiabatic molecular dynamics (NAMD) simulations can help meet this need. In Chapter 2, the theoretical background necessary for discussing NAMD simulations is provided, and the approximations needed to make NAMD possible for large chemical systems is introduced, such as the neglect-of-back-reaction approximation (NBRA). Chapter 3 critically discusses how the NBRA may miss important physics needed for accurate NAMD simulations and presents a comparative analysis study that assesses the performance of various correction schemes that reintroduce the missing physics into NBRA-NAMD simulations. In Chapter 4, a highly efficient NAMD method is presented that can easily simulate the phonon-driven nonradiative relaxation dynamics of excess electronic energy in systems that contain hundreds of atoms. This method is applied to study the relaxation of hot electrons in a series of silicon nanocrystals whose surface is terminated with either hydrogen or fluorine atoms. In the fifth chapter, a new NAMD framework capable of treating electronic states beyond the commonly employed single-particle approximation is introduced. In this framework, electronic excited states are treated at the linear-response time-dependent density functional theory level. The first part of Chapter 5 focuses on the method's application to excess electronic energy relaxation in CdSe and Si nanocrystals. The second part of Chapter 5 focuses on the method's application to excess electronic energy relaxation in periodic perovskite systems. Chapter 6 describes an efficient algorithm for capturing the quantum effects of nuclei in MD simulations. Chapter 7 presents unpublished work that may serve as a good starting point for future research. Finally, overarching conclusions and general remarks regarding the studies discussed in this dissertation are made
Electronic reproduction. Ann Arbor, Mich. : ProQuest, 2021
