Electronic coupling calculations with transition charges, dipoles, and quadrupoles derived from electrostatic...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Electronic coupling is crucial for understanding energy transfer processes.
• The original TrESP method considered only transition charge interactions.
• Limitations in accurately describing electronic coupling necessitate improved methods.

Purpose of the Study:

• To propose an extended TrESP method (TrESP-CDQ) incorporating transition dipoles and quadrupoles.
• To enhance the accuracy of electronic coupling calculations.
• To analyze the contributions of different multipole moments to electronic coupling.

Main Methods:

• Development of the TrESP-CDQ method based on electrostatic potential.
• Utilizing self-consistent transition densities in the electrostatic potential fitting procedure.
• Performing test calculations on helium, methane, and ethylene dimers.

Main Results:

• The TrESP-CDQ method significantly improves the description of electronic coupling compared to the original TrESP method.
• Self-consistent treatment of transition densities enhances calculation accuracy.
• Transition charge interactions were found to have a negligible contribution to electronic coupling.

Conclusions:

• The TrESP-CDQ method offers a more accurate approach for calculating electronic coupling.
• Transition density distribution significantly impacts multipole moment magnitudes.
• This method is valuable for elucidating excitation-energy transfer mechanisms.