Surface hopping dynamics including intersystem crossing using the algebraic diagrammatic construction method.

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• Nonadiabatic dynamics simulations are crucial for understanding photochemical processes.
• Intersystem crossing (ISC) is a key phenomenon in photochemistry, particularly in organic molecules.
• Accurate theoretical methods are needed to model ISC efficiently.

Purpose of the Study:

• To implement and evaluate the algebraic diagrammatic construction to second order [ADC(2)] ab initio electronic structure method for nonadiabatic dynamics simulations.
• To enable computationally efficient, reliable, and user-friendly simulations of intersystem crossing in organic molecules.
• To assess the performance of the ADC(2) method in conjunction with the SHARC (surface hopping including arbitrary couplings) dynamics method.

Main Methods:

• Implementation of the ADC(2) ab initio electronic structure theory within the SHARC dynamics framework.
• Utilizing the SHARC method for surface hopping including arbitrary couplings.
• Application and evaluation of the implemented methodology to the 2-thiouracil molecule.

Main Results:

• The ADC(2) method provides reliable excited-state energies, wave functions, and spin-orbit coupling terms for 2-thiouracil.
• Nonadiabatic dynamics simulations using ADC(2)/SHARC show favorable agreement with high-level multi-state complete active space perturbation theory results.
• The implementation enables computationally efficient and reliable simulations of intersystem crossing.

Conclusions:

• The developed ADC(2)-based nonadiabatic dynamics approach is a reliable and efficient tool for studying intersystem crossing in organic molecules.
• This methodology facilitates accurate investigations of excited-state dynamics and photochemical mechanisms.
• The findings support the use of ADC(2) for simulating complex quantum phenomena in molecular systems.