Electronic Structure Methods for the Description of Nonadiabatic Effects and Conical Intersections

Area of Science:

• Theoretical Chemistry
• Quantum Chemistry
• Photochemistry

Background:

• Nonadiabatic effects are fundamental to photophysics and photochemistry.
• Conical intersections are key to ultrafast transitions between electronic states.

Purpose of the Study:

• To review electronic structure methods for describing nonadiabatic processes.
• To discuss requirements for modeling conical intersections and nonadiabatic couplings.
• To highlight recent advancements in methodology and implementation.

Main Methods:

• Focus on electronic structure aspects of nonadiabatic processes.
• Analysis of common excited-state electronic structure methods.
• Evaluation of methods for describing conical intersections and nonadiabatic couplings.

Main Results:

• Electronic structure methods must accurately capture conical intersections and nonadiabatic couplings.
• Commonly used excited-state methods have limitations in describing these effects.
• Recent developments aim to expand methodology and improve nonadiabatic coupling implementation.

Conclusions:

• Accurate theoretical descriptions of nonadiabatic processes rely on advanced electronic structure methods.
• Further development is needed to fully capture the nuances of conical intersections and nonadiabatic couplings.
• This review provides insights into current capabilities and future directions in the field.