Our group develops theoretical methods that can treat various quantum and classical degrees of freedom (DOF) on a consistent dynamical footing. In particular, we are interested in developing non-adiabatic quantum dynamics approaches based on real-time and imaginary-time path-integral formalism.
Coherent State Mapping and Ring Polymer Molecular Dynamics
We develop new quantum dynamics approaches that can accurately describe both electronic non-adiabatic dynamics and nuclear quantum effects. Our approaches take advantage of using a classical-like description of the collective electronic degrees of freedom (DOF) as well as quantum nuclear DOF (such as protons), thus treating all the DOF on an equal dynamical footing, address the long-lasting challenge of inconsistency between the quantum and classical DOFs.
Coherent State Mapping Ring-Polymer Molecular Dynamics for Non-Adiabatic quantum propagations
S. Chowdhury and P. Huo, J. Chem. Phys. 147, 214109 (2017).
Ring Polymer Surface-Hopping: Incorporating Nuclear Quantum Effects Into Non-Adiabatic Molecular Dynamics Simulations
F. A. Shakib and P. Huo, J. Phys. Chem. Lett. 8, 3073 (2017).
Quasi Diabatic Representation for on-the-fly Quantum Dynamics
We develop a Quasi-Diabatic scheme that allows us to combine diabatic dynamics approaches with adiabatic electronic structure calculations for direct quantum dynamics propagation. This scheme enables us to perform fast, scalable yet accurate quantum dynamics in “real” molecular systems, solving one of the central challenges in modern theoretical chemistry.
Quasi Diabatic Representation for Nonadiabatic Dynamics Propagation
A. Mandal, S. Yamijala and P. Huo J. Chem. Theory Comput. (2018)
Quasi Diabatic Propagation Scheme for Symmetric Quasi Classical Dynamics
J. S. Sandoval, A. Mandal, and P. Huo (submitted) (2018)
Photoinduced Quantum Dynamics
We will apply new quantum dynamics approaches to directly simulate solar energy conversion processes and obtain detailed mechanistic insights. Such dynamical insights, which have been historically overlooked by studies employing static electronic structure calculations, will inspire new design principles to improve the conversion efficiency of solar cells. We focus on investigating the fundamental mechanisms of three ubiquitous, complex, and poorly understood reactions: (1) photoinduced charge transfer (CT) dynamics in organic photovoltaics (OPVs), (2) singlet fission (SF) processes in polyacene dimer and clusters, and (3) photoinduced proton-coupled electron transfer (PI-PCET) reactions.
Singlet Fission and Charge transfer Dynamics
We apply real-time path-integral approach to investigate the charge-transfer (CT)-mediated singlet fission quantum dynamics in interesting molecular systems. Our pathintegral method gives reliable charge transfer dynamics across various reaction regimes and temperatures. Our investigation reveal promising design principles for more efficient singlet fission as well as organic photovoltaic materials.
Enhancing Singlet-Fission Dynamics by Suppressing Destructive Interference between Charge-Transfer Pathways
M. Castellanos and P. Huo, J. Phys. Chem. Lett. 8, 2480 (2017).
Photoinduced Proton Coupled Electron Transfer
Initiated through photoexcitation process, PI-PCET reactions play a critical role in solar energy conversion processes. At the same time, they are promising for providing new and unique reactivities which are not directly accessible in thermally activated PCET reactions. We develop methods to simulate PI-PCET reactions which helps us understand the fundamental mechanistic principles of PI-PCET.
Investigating Photoinduced Proton Coupled Electron Transfer Reaction using Quasi Diabatic Dynamics Propagation
A. Mandal, F. A. Shakib, and P. Huo (submitted) (2018).