Theories and Computational Methods for Quantum Transitions in Solar Energy Conversion, Imaging, and Sensing 

Seogjoo J. Jang, PhD 

Department of Chemistry and Biochemistry, Queens College, City University of New York & PhD Programs in Chemistry and Physics, Graduate Center, City University of New York  

Great advances have been made over many decades for the characterization of electronic excited states and their quantum transitions in complex molecular environments. To this end, depending on the nature of systems and environments, the quantum transitions can be characterized by rates or more complete quantum dynamical description. For the calculation of rates of exciton transfer and decay, Fermi’s golden rule (FGR) has been widely and successfully used for various molecular systems.   However, in its applications to complex molecular systems, there are some ambiguities and issues requiring further refinement and development of FGR.  This talk introduces our recently developed quantum rate theories for resonance energy transfer and nonradiative decay, which can account for new quantum effects that were missing in previously established theories.   Applications of some of these to photosynthetic light harvesting complexes and organic dye molecules demonstrate the success of improved rate theories for quantitative description of exciton transfer and nonradiative decay rates.  For transitions that go beyond simple rate description, more advanced quantum dynamics approaches become necessary. To this end, we have been making efforts to develop various advanced open system quantum dynamics methods. These include various approaches incorporating advanced quantum dynamics methods such as polaron transformed quantum master equation approaches. Implications and the utility of these methods for driven open system quantum dynamics processes such as in quantum sensing are discussed.