(SOS1-)PBE-DH-INVEST double hybrid functionals for INVEST systems: Validation for azaphenalene compounds

Area of Science:

• Computational chemistry
• Theoretical chemistry
• Quantum chemistry

Background:

• INVEST systems are vital for organic light-emitting diodes and photocatalysis.
• Accurate theoretical description of INVEST systems is challenging due to electron correlation and double excitations.
• Conventional time-dependent density functional theory methods often fail to capture these effects.

Purpose of the Study:

• To assess the performance of PBE-DH-INVEST and SOS1-PBE-DH-INVEST for describing INVEST systems.
• To evaluate their accuracy in predicting excitation energies and singlet-triplet energy gaps.
• To compare these new functionals against established methods and reference data.

Main Methods:

• Utilized the PBE-DH-INVEST and SOS1-PBE-DH-INVEST double-hybrid density functionals.
• Employed the Tamm-Dancoff approximation with the aug-cc-pVDZ basis set.
• Computed S1 ← S0 and T1 ← S0 excitation energies and ΔEST values for azaphenalene derivatives (AP117 set).
• Compared results against CC2 reference data.

Main Results:

• PBE-DH-INVEST demonstrated a robust description of excitation energies and singlet-triplet gaps.
• The inclusion of double-excitation contributions (Δ(D)) was essential for capturing the inverted energetic ordering of INVEST systems.
• SOS1-PBE-DH-INVEST provided competitive results with lower computational cost but slightly higher errors.
• Both functionals showed marked improvement over hybrid treatments lacking double-excitation corrections.

Conclusions:

• PBE-DH-INVEST and its variant offer reliable theoretical tools for studying INVEST systems.
• Accurate modeling of double excitations is critical for understanding INVEST system properties.
• These functionals advance the theoretical description of materials relevant to optoelectronics and catalysis.