Subject Area



Simulating excitation energy transfer (EET) in molecular materials is of crucial importance for the development of and understanding of materials such as organic photovoltaics and photosynthetic systems and further development of novel materials. The Hierarchy of Pure States (HOPS) is an exact framework for the time evolution of an open quantum system in which a hierarchy of stochastic wave functions are propagated in time. The adaptive HOPS (adHOPS) method achieves size-invariant scaling with the number of simulated molecules for sufficiently large aggregates by using an adaptive basis that moves with the excitation through the material. To demonstrate the power of the reduced scaling of adHOPS in realistic molecular materials we build a large hexagonally-packed supercomplex constructed of B850 rings from the photosynthetic antenna complex of purple bacteria, light harvesting 2 (LH2). We use adHOPS to simulate EET in the supercomplex to understand the mechanism of transport in LH2 and demonstrate that we can extract mechanistic insight about excited state process in molecule materials on an unprecedented scale.

Degree Date

Spring 2023

Document Type


Degree Name





Doran I.G.B. Raccah

Second Advisor

Devin Matthews

Third Advisor

Peng Tao



Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License