Theory and computations in quantum dynamics: nonadiabatic molecular dynamics, non-local quantum effects and quantum entanglement, large-scale computations. Theory and simulation of charge, spin, and excitation energy transfer in solar energy conversion materials; electron-vibronic coupling in functional nanomaterials.
Our research revolves around the following main directions:
- Quantum dynamics. We are interested in fundamental theory and methodology of quantum dynamics. Both are needed for accurate and efficient quantum dynamics simulations. Our present focus is on the trajectory-based descriptions of nonadiabatic processes (e.g. charge transfer or excitation energy relaxation). Within this framework, we look to understand the sources of inaccuracies in approximate quantum dynamics techniques and eventually fix them. In particular, the topics being addressed are: the representation invariance (dependence on basis set), the non-local quantum effects (e.g. tunneling, uncertainty principle, decoherence), as well as the quantum entanglement (trajectory cross-talk in the ensemble description).
- Large–scale computations. We are interested in simulating quantum dynamical processes in large atomistic systems. To address the scale limitations, we develop efficient computational strategies and new theoretical approaches. The main foci are on the semiempirical and model Hamiltonians as well as on the fragmentation-based linear-scaling methods for electronic structure computations. We implement and maintain our own codes for performing quantum dynamics simulations in atomistic and model systems.
- Solar energy conversion materials and functional nanomaterials. The theories and computational tools we develop are ultimately used to gain mechanistic insights into operation of solar energy conversion (photovoltaics, photocatalytics) materials as well as functional nanomaterials (e.g. light-driven nanomachines). We investigate dynamics of charge and spin transfer, excitation energy relaxation, and light-induced nuclear dynamics (e.g. photochemical transformations). The systems we study include condensed crystalline or soft (bio) matter, nanoscale clusters (quantum dots) and molecular complexes, as well as interfaces and exotic 1D (nanotubes) and 2D structures.