Integrating Nuclear Quantum Effects into Nonadiabatic Dynamics with NEO-SHARC

Objective

This project aims to develop a hybrid SHARC-NEO framework to address one of the longstanding challenges of theoretical photchemistry, multi-dimensional nonadiabatic dynamics incorporating nuclear quantum effects. Surface Hopping including ARbitrary Coupling (SHARC) software package developed by the Gonz\'alez group, successfully captures electronic nonadiabatic dynamics, while the Nuclear–Electronic Orbital (NEO) approach, pioneered by Hammes-Schiffer and coworkers, provides a rigorous quantum treatment of light nuclei. However, no methodology exists that unifies these two perspectives in multidimensional condensed phase systems. The fellowship will fill this gap by developing a hybrid SHARC–NEO framework. In this approach, heavy nuclei are propagated classically, electronic states are treated with SHARC, and selected nuclei are described quantum mechanically through NEO. The project will proceed in well-categorized stages, interfacing Q-chem (NEO) with SHARC, extending wfoverlap module of SHARC for NAC, benchmarking on shared-proton systems against cNEO simulations and experimental results, and extending to photochemical and photocatalytic applications. Successful completion of the project would result in an open source module within the SHARC package, which would be capable of treating light-nuclei like protons quantum mechanically in complex phtochemical and photobiological systems.