Non-adiabatic dynamics, i.e. transitions between different electronic and/or vibrational states, play a crucial role in the dynamics of charge transfer (CT) reactions in many photocatalytic systems. Due to the quantum mechanical nature of these reactions, dynamics cannot be described purely in the frame of the Born-Oppenheimer approximation, and the complexity of the problem increases due to the effect of nuclear quantum effects (NQEs), namely zero-point energy and tunneling. Therefore, the precise treatment of non-adiabatic dynamics of CT reactions subject to NQEs is challenging. The newly developed ring polymer surface hopping (RPSH) method promises of providing a computationally efficient approach with acceptable accuracy to investigate CT reactions. In this method, NQEs are captured with the Feynman’s imaginary-time path-integral formalism while non-adiabatic transitions are incorporated based on Tully’s fewest-switches surface hopping algorithm. We have improved the RPSH method compared to its earliest versions on several grounds and have created the surface hopping and ring polymer software package, shortened as SHARP pack. The performance of SHARP pack is extensively compared with numerically exact calculations using a myriad of well-established quantum models, from Tully’s three infamous two-state models to the condensed-phase spin-boson model, at different reaction regimes and temperatures. The RPSH method at the heart of SHARP pack yields the correct distribution of the electronic states’ population that is in quantitative agreement with the exact quantum results at both high and low-temperature limits. Investigating results from the two-level system model, we demonstrate that SHARP pack can decently describe quantum tunneling, zero-point energy, and decoherence. The results have important implications for method development and understanding nuclear quantum effects within non-adiabatic dynamics simulations to study photo-induced CT reactions.

Non-adiabatic dynamics simulations in condensed phases via ring polymer surface hopping: Introducing SHARP software package

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.