An efficient implementation of semiempirical quantum-chemical orthogonalization-corrected methods for excited-state...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Accurate computation of excited-state dynamics is crucial for understanding photophysical processes.
• Semiempirical methods offer a computationally feasible alternative to ab initio methods for larger systems.

Purpose of the Study:

• To present an efficient implementation of configuration interaction with single excitations (CIS) for semiempirical methods.
• To enable simulations of excited-state nonadiabatic dynamics using Tully's fewest switches algorithm.
• To develop an accurate and efficient method for calculating nonadiabatic couplings.

Main Methods:

• Configuration Interaction with Single excitations (CIS) for OMx and MNDO-type methods.
• Tully's fewest switches algorithm for surface hopping simulations.
• Semiempirical evaluation of nonadiabatic couplings.

Main Results:

• An efficient CIS implementation for semiempirical methods was developed.
• A significant speedup in calculating nonadiabatic couplings for medium-size molecules was achieved.
• The method is suitable for long nonadiabatic dynamics simulations.

Conclusions:

• The developed semiempirical CIS implementation enables efficient simulations of excited-state nonadiabatic dynamics.
• The method provides a valuable tool for investigating ultrafast energy transfer processes.
• This approach is particularly useful for studying complex molecular systems like dendrimers.