Time-Dependent Multiconfigurational Short-Range Density Functional Theory with Generalized Valence Bond Wave...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Accurate calculation of molecular properties is crucial in chemistry.
• Existing methods like GVB-PP have limitations in capturing dynamic correlation.
• Range-separated density functional theory offers a way to include dynamic correlation.

Purpose of the Study:

• To present a theory and implementation of TD-GVB-srDFT.
• To benchmark TD-GVB-srDFT for excitation energies and spin-spin coupling constants.
• To compare TD-GVB-srDFT with other theoretical methods.

Main Methods:

• Time-dependent multiconfigurational range-separated density functional theory (TD-GVB-srDFT).
• Generalized valence bond perfect-pairing (GVB-PP) wave functions.
• Direct Hessian techniques for wave function optimization and linear response.
• Range-separation of the Coulomb potential.
• Generalized Tamm-Dancoff approximation (gTDA) for triplet excitations.

Main Results:

• TD-GVB-srDFT significantly improves excitation energies compared to GVB-PP.
• Accuracy for excitation energies is comparable to CAS-srDFT (mean absolute deviation of 0.2 eV).
• GVB-srDFT accurately computes spin-spin coupling constants for organic molecules.
• Both GVB-srDFT and CAS-srDFT accurately reproduce fluorine-metal couplings in transition metal complexes with gTDA.

Conclusions:

• TD-GVB-srDFT provides a computationally efficient and accurate method for electronic structure calculations.
• The method offers a significant improvement over the underlying GVB-PP model.
• TD-GVB-srDFT is a promising tool for studying molecular properties, especially in cases with significant dynamic correlation.