Nonadiabatic Excited-State Molecular Dynamics with an Explicit Solvent: NEXMD-SANDER Implementation

Area of Science:

• Computational Chemistry
• Molecular Dynamics
• Quantum Mechanics

Background:

• Simulating photoinduced dynamics in large conjugated molecules is computationally challenging.
• Understanding solvent effects on excited-state processes is crucial for molecular optical properties.

Purpose of the Study:

• To couple the NEXMD and SANDER packages for QM/MM simulations of photoinduced dynamics.
• To investigate solvent-dependent effects on excited-state behavior in conjugated molecules.

Main Methods:

• Integration of the nonadiabatic excited-state Molecular Dynamics (NEXMD) package with the SANDER package (AMBERTOOLS).
• Utilized quantum mechanics/molecular mechanics (QM/MM) methodology.
• Employed the fewest switches surface hopping algorithm for quantum transitions.
• Simulated a substituted polyphenylenevinylene oligomer (PPV3-NO2) in vacuum and methanol.

Main Results:

• Successfully simulated photoinduced dynamics of a multichromophoric molecule in explicit solvent.
• Analyzed the impact of solvent molecules on excited-state behavior and optical properties.
• Demonstrated the ability to model solvent reorganization and charge-separated states.

Conclusions:

• The NEXMD-SANDER QM/MM implementation is a valuable tool for studying solvent effects in photoexcited molecules.
• This approach can qualitatively reproduce experimentally observed solvent-dependent phenomena.
• Provides insights into electron transfer and excited-state stabilization in solution.