Charge transfer processes: the role of optimized molecular orbitals

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Materials Science

Background:

• Charge transfer (CT) reactions are fundamental in chemical and physical processes.
• Accurate theoretical descriptions of CT require considering electronic reorganization.
• Previous models often overlooked the role of inner-shell electronic changes.

Purpose of the Study:

• To analyze the influence of molecular orbitals on charge transfer reactions.
• To investigate the impact of inner-shell electronic changes on CT processes.
• To develop a quantum chemistry approach for describing redox reactions.

Main Methods:

• Wave function-based calculations were employed.
• A state-specific approach using adapted complete active space self-consistent field (CASSCF) methodology was utilized.
• Analysis was performed on systems including an organic radical and an inorganic crystalline material.

Main Results:

• Changes in inner electronic shells significantly affect CT reactions.
• Electronic reorganization can reduce CT vertical transition energy by up to 66%.
• The adapted CASSCF method shows good agreement with experimental spectroscopy of CT processes.

Conclusions:

• Inner-shell electronic reorganization plays a crucial role in CT reactions.
• A partitioning of relaxation energy into valence and inner shells clarifies their relative importance.
• This work provides a pathway for detailed quantum chemical descriptions of redox reactions.