Excited State Intramolecular Proton Transfer with Nuclear-Electronic Orbital Ehrenfest Dynamics

Area of Science:

• Computational Chemistry
• Quantum Dynamics
• Theoretical Chemistry

Background:

• The nuclear-electronic orbital (NEO) framework with Ehrenfest dynamics offers a method for simulating coupled nuclear-electronic dynamics.
• Previous work demonstrated the accuracy of the NEO-Ehrenfest approach combined with a semiclassical traveling proton basis for predicting molecular vibrational frequencies.

Purpose of the Study:

• To thoroughly analyze the validity and convergence of the semiclassical traveling proton basis method.
• To investigate excited-state intramolecular proton transfer processes using NEO-Ehrenfest dynamics simulations.

Main Methods:

• Detailed analysis of the semiclassical traveling proton basis method.
• Execution of NEO-Ehrenfest dynamics simulations for excited-state intramolecular proton transfer.
• Investigation of nuclear quantum effects on reaction rates and kinetic isotope effects.

Main Results:

• The semiclassical traveling proton basis method's validity and convergence behavior were elucidated.
• Simulations revealed that nuclear quantum effects significantly impact proton transfer reaction rates and kinetic isotope effects.
• The delocalized nature of the quantum nuclear wave function was identified as a key factor.

Conclusions:

• Nuclear quantum effects play a vital role in coupled nuclear-electronic dynamical processes.
• The NEO-Ehrenfest approach is a powerful tool for gaining insights and making predictions in these complex systems.
• This study highlights the importance of incorporating quantum mechanical descriptions of nuclei in molecular dynamics simulations.