Simulating Quantum Chemical Dynamics in Condensed Phases: Methodological Developments and Applications

Quantum effects play a critical role in many problems of chemical dynamics in condensed phases. In this presentation, I will introduce recent progress from our group on the development and application of the hierarchical equations of motion (HEOM) method, a non-perturbative framework for accurately capturing the influence of environmental degrees of freedom on quantum systems. I will first highlight recent algorithmic advances that extend the method’s applicability to more complex systems. These include efficient treatments of the exponential decomposition of bath correlation functions for general spectral densities and low-temperature conditions, as well as the integration of tensor network techniques to enable HEOM propagation involving thousands of effective modes. Several applications of the HEOM method will then be presented, including charge transport and separation dynamics in organic semiconductors; quantum coherence in excitation energy transfer in photosynthetic light-harvesting complexes and related ultrafast spectroscopic phenomena; and the dynamics of systems under strong light-matter interactions.