Highly efficient surface hopping dynamics using a linear vibronic coupling model.

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Photochemistry

Background:

• Simulating molecular photodynamics is crucial for understanding chemical reactions.
• Existing methods like surface hopping can be computationally expensive.
• Accurate modeling requires capturing electron-vibrational interactions.

Purpose of the Study:

• To implement an efficient linear vibronic coupling (LVC) model within surface hopping dynamics.
• To provide a blackbox parameterization for the LVC model.
• To enable faster and more accurate simulations of molecular photodynamics and benchmarking.

Main Methods:

• Implementation of the LVC model in a surface hopping framework.
• Development of blackbox utilities for LVC model parameterization.
• Application to SO2, adenine, 2-aminopurine, 2-thiocytosine, and 5-azacytosine.

Main Results:

• Achieved a 1000x reduction in computational cost for SO2 photodynamics compared to on-the-fly simulations.
• Accurately reproduced SO2 absorption spectrum beyond the Condon approximation and intersystem crossing timescales.
• Correctly predicted ultrafast decay in adenine versus extended lifetime in 2-aminopurine.
• Successfully predicted intersystem crossing in 2-thiocytosine and its absence in 5-azacytosine.

Conclusions:

• The LVC model offers a highly efficient approach for qualitative and semi-quantitative photodynamics simulations.
• This method provides a valuable tool for benchmarking surface hopping computations.
• The model demonstrates broad applicability across various molecular systems, including nucleobases.