Mapping variable ring polymer molecular dynamics: a path-integral based method for nonadiabatic processes.

Area of Science:

• Quantum Chemistry
• Computational Physics
• Molecular Dynamics

Background:

• Simulating multi-electron quantum processes is computationally challenging.
• Existing methods often struggle to accurately capture the real-time dynamics of electronic transitions and nuclear motion.

Purpose of the Study:

• To introduce a novel computational method, mapping-variable ring polymer molecular dynamics (MV-RPMD), for direct simulation of multi-electron processes.
• To demonstrate the accuracy and capabilities of MV-RPMD in modeling quantum dynamics.

Main Methods:

• MV-RPMD extends the ring polymer molecular dynamics (RPMD) concept.
• It utilizes an exact, imaginary time path-integral representation of the quantum Boltzmann operator.
• Employs continuous Cartesian variables for both electronic states and nuclear degrees of freedom.

Main Results:

• MV-RPMD accurately calculates real-time thermal correlation functions for two-state single-mode models.
• The method shows accuracy across varying coupling strengths and system asymmetries.
• The ensemble of classical trajectories preserves the Boltzmann distribution.

Conclusions:

• MV-RPMD provides a direct probe into the real-time coupling between electronic state transitions and nuclear dynamics.
• This method offers a powerful tool for studying complex quantum phenomena in molecular systems.