Open-Shell-Character-Based Molecular Design Principles: Applications to Nonlinear Optics and Singlet Fission

Area of Science:

• Quantum chemistry
• Molecular design
• Materials science

Background:

• Open-shell character, including diradical character, is a quantum chemically defined metric for ground-state molecular systems.
• It quantifies effective bond weakness and electron correlation strength, though it is not a direct observable.
• This character is linked to specific excited states, suggesting correlations with related physicochemical properties.

Purpose of the Study:

• To explain molecular design principles based on open-shell character.
• To introduce applications of these principles in designing efficient functional molecular systems.
• To explore the mechanism of physicochemical properties influenced by open-shell character.

Main Methods:

• Quantum chemical calculations to determine open-shell character.
• Correlation analysis between open-shell character and molecular properties.
• Computational and theoretical investigations of molecular design strategies.

Main Results:

• Established open-shell character as a key descriptor for molecular properties.
• Demonstrated the utility of open-shell character in predicting and designing functional materials.
• Identified correlations between open-shell character and performance in nonlinear optical and singlet fission systems.

Conclusions:

• Open-shell character provides a valuable framework for understanding and designing molecular systems.
• This approach facilitates the rational design of materials with enhanced nonlinear optical and singlet fission capabilities.
• The study opens new avenues for developing efficient molecular functional systems based on quantum chemical principles.