Dipole moments of molecules with multi-reference character from optimally tuned range-separated density functional...

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Accurate dipole moments require precise molecular geometry and charge distribution prediction.
• Density functional theory (DFT) methods often struggle with multi-reference systems compared to single-reference ones.
• Predicting dipole moments for multi-reference molecules presents a significant challenge in computational chemistry.

Purpose of the Study:

• To develop novel density functionals for accurate dipole moment calculations of multi-reference molecules.
• To investigate optimally tuned range-separated hybrid (OT-RSH) functionals for systems containing main-group and transition metals.
• To improve upon existing DFT approximations for challenging molecular systems.

Main Methods:

• Development and application of nonempirically tuned range-separated hybrid density functionals (OT-RSHs).
• Systematic scanning of controlling factors within OT-RSHs, including exchange contributions and range-separation parameters.
• Comparative analysis against standard range-separated functionals and other DFT approximations.

Main Results:

• The newly developed OT-RSHs provide an improved description of dipole moments for multi-reference molecules.
• These functionals demonstrate superior prediction quality compared to conventional and recently proposed DFT approximations.
• Optimized OT-RSHs effectively capture the charge distribution in complex molecular systems.

Conclusions:

• Optimally tuned range-separated hybrid functionals offer a robust approach for accurate dipole moment prediction in multi-reference systems.
• The developed OT-RSHs represent a significant advancement over existing DFT methods for these challenging molecules.
• This work provides reliable computational tools for studying the electronic properties of complex molecules.