Can Semilocal Approximations to the Embedding Potential Tackle Charge-Transfer-to-Solvent Excitations? An Aqueous...

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• Frozen-density embedding theory (FDET) is a formal framework for density-dependent embedding potentials.
• FDET methods involve approximations in the exchange-correlation potential, wave function localization, and environment density generation.
• The standard FDET protocol accurately predicts excitation energies for localized excitations but may fail for charge-transfer excitations.

Purpose of the Study:

• To investigate the applicability of FDET for charge-transfer-to-solvent (CTTS) excitations.
• To demonstrate that CTTS excitations can be treated using FDET-based methods.
• To identify necessary refinements to the standard FDET protocol for accurate CTTS excitation energy calculations.

Main Methods:

• Utilizing frozen-density embedding theory (FDET) as the foundational method.
• Applying approximations for the bifunctional potential, wave function localization, and environmental electron density.
• Modifying the standard FDET protocol to accommodate the characteristics of CTTS excitations.

Main Results:

• FDET-based methods can successfully treat charge-transfer-to-solvent excitations.
• The standard FDET protocol requires adjustments for accurate CTTS excitation energy calculations.
• Refined approximations within FDET enable accurate treatment of these challenging excitations.

Conclusions:

• Frozen-density embedding theory is adaptable for studying charge-transfer-to-solvent excitations.
• The standard FDET protocol needs modification for CTTS excitations.
• This work extends the utility of FDET to a broader range of electronic excitation phenomena.