A Flexible, Automated, and Basis-Set-Insensitive Domain-Based Charge-Transfer Decomposition for Correlated Wave...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Analyzing excited-state properties is crucial for understanding molecular behavior.
• Existing methods for charge-transfer (CT) analysis can be limited by basis-set dependence and complexity.

Purpose of the Study:

• To present a flexible, automated, and basis-set-insensitive framework for domain-based charge-transfer (CT) decomposition.
• To enable the dissection of excited-state character into local and CT excitations, quantifying individual contributions.

Main Methods:

• Developed a novel framework compatible with any configuration interaction (CI)-type excited-state wave function.
• Introduced two domain-accumulation strategies (strict partitioning and weighted approach) for translating hole-particle excitations.
• Validated the approach using EOM-CCSD and EOM-pCCD+S for inter- and intramolecular CT excitations across various basis sets.

Main Results:

• The framework successfully decomposes excited-state character into local and domain-based CT excitations.
• CT character was found to be largely independent of the basis set used in calculations.
• Both domain-accumulation strategies yielded consistent results, demonstrating robustness.

Conclusions:

• The presented framework offers a robust and versatile tool for charge-transfer analysis in computational chemistry.
• It provides a domain-based resolution of excitation character applicable to diverse computational setups and excited-state models.
• The basis-set independence of the CT character enhances the reliability and broad applicability of the method.