Multiconfiguration Density-Coherence Functional Theory.

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• Accurate description of electron correlation in molecules is crucial for computational chemistry.
• Existing methods like multiconfiguration pair-density functional theory (MC-PDFT) and CASPT2 are computationally expensive.
• Developing new theoretical frameworks is essential for advancing molecular modeling.

Purpose of the Study:

• Introduce a novel theoretical framework: multiconfiguration density coherence functional theory (MC-DCFT).
• Establish a new method for defining density functionals tailored for multiconfiguration wave functions.
• Assess the performance of MC-DCFT in calculating molecular properties.

Main Methods:

• Developed MC-DCFT, utilizing the one-particle density matrix in coordinate representation.
• Converted existing functionals (PBE, BLYP, PW91) into density coherence functionals.
• Introduced two adjustable parameters into the converted functionals.
• Calculated dissociation curves for H2, F2, N2, and HF molecules.

Main Results:

• MC-DCFT successfully calculated bond dissociation energies for diatomic molecules.
• The accuracy of MC-DCFT results was comparable to established methods like MC-PDFT and CASPT2.
• The introduction of two parameters significantly improved the accuracy of the calculated energies.

Conclusions:

• MC-DCFT offers a viable and accurate approach for electronic structure calculations.
• The theory demonstrates the potential for developing robust multiconfiguration density functional theories.
• This work paves the way for more efficient and accurate quantum chemical computations.