Multi-dimensional Electronic Dynamics beyond the Dipole Approximation

University Of Washington, Seattle WA

Investigators

Abstract

Xiaosong Li of the University of Washington is supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry Division and the Computational and Data-Enabled Science and Engineering program in the Division of Advanced Cyberinfrastructure to develop computational methods and open-source software to study the dynamics of electrons driven by electromagnetic fields. Electronic processes influenced by multiple electromagnetic fields underlie the functionality of many technologically-important materials. The methods developed by Li and his research group yield new and powerful avenues to facilitate scientific discoveries of materials that exhibit desirable optical properties. The project also provides a mechanism for advanced interdisciplinary education and training in the areas of inorganic, theoretical, physical, and materials chemistry. The project prepares participating undergraduate and graduate students for future careers in science, engineering, and education. Through a combination of high-school and community outreach and undergraduate research mentoring, this project promotes and fosters participation of a broad spectrum of youth in science and engineering activities. This project lays the theoretical groundwork for modeling time-resolved, multidimensional electronic spectroscopy, with energies ranging from the UV to X-ray regions of the spectrum and modulated by the delays between pulses, completely within the first-principles framework. On the one hand, the development is able to reveal the physical mechanisms that drive excited state chemical processes/phenomena, which is fundamental to energy research. For example, coherent excitonic and charge transfer dynamics is one potential application. On the other hand, the algorithmic advances greatly broaden the application of excited state electronic structure theory in the non-perturbative, non-linear regime. Here the process of interest requires a description of the system-field interaction that goes beyond the electric-dipole approximation. This research activity is unique in that it seamlessly integrates time-dependent quantum mechanical theories and spectral analysis software tools with modular high-performance numerical libraries that are highly parallelized, extensible, reusable, community-driven, and open-sourced. The research goals are to provide a direct path to the discovery and design of molecules and materials that demonstrate new or enhanced high-order optical, magnetic, electronic, and plasmonic features.