Extending Non-Perturbative Simulation Techniques for Open-Quantum Systems to Excited-State Proton Transfer and Ultrafast Non-Adiabatic Dynamics

TL;DR

This paper extends the TEDOPA method to simulate complex open quantum systems involving ultrafast excited-state proton transfer and non-adiabatic dynamics, enabling accurate quantum-level insights into photochemical processes.

Contribution

The work introduces an extension of the TEDOPA approach to handle high-dimensional vibronic states and dissipative dynamics in excited-state proton transfer and non-adiabatic processes.

Findings

Successfully modeled ultrafast proton transfer with hundreds of vibrations.

Enabled visualization of diabatic and adiabatic potential surface dynamics.

Provided a framework for exact quantum simulations of complex photochemical reactions.

Abstract

Excited state proton transfer is an ubiquitous phenomenon in biology and chemistry, spanning from the ultrafast reactions of photo-bases and acids to light-driven, enzymatic catalysis and photosynthesis. However, the simulation of such dynamics involves multiple challenges, since high-dimensional, out-of-equilibrium vibronic states play a crucial role, while a fully quantum description of the proton's dissipative, real-space dynamics is also required. In this work, we extend the powerful Matrix Product State approach to open quantum systems (TEDOPA) to study these demanding dynamics, and also more general non-adiabatic processes that can appear in complex photochemistry subject to strong laser driving. As an illustration, we initially consider an open model of a four-level electronic system interacting with hundreds of intramolecular vibrations that drive ultrafast excited state proton transfer, as well as an explicit photonic environment that allows us to directly monitor the resulting dual fluorescence in this system. We then demonstrate how to include a continuous 'reaction coordinate' of the proton transfer that allows numerically exact simulations that can be understood, visualized and interpreted in the familiar language of diabatic and adiabatic dynamics on potential surfaces, while also retaining an exact quantum treatment of dissipation and driving effects that could be used to study diverse problems in ultrafast photochemistry.