Computing Reaction Kinetics with MC-PDFT-OPESf: Combining Multireference Electronic Structure Theory and Enhanced...

Area of Science:

• Computational Chemistry
• Chemical Kinetics
• Quantum Chemistry

Background:

• Accurate rate constants are vital for optimizing catalytic reactions.
• Enzymes, metalloproteins, and heterogeneous catalysts present computational challenges due to multiconfigurational reaction sites and high activation barriers.
• Efficient sampling of reactive transitions is often hindered by these challenges.

Purpose of the Study:

• To develop and demonstrate an efficient computational approach for determining accurate reaction kinetics.
• To address the dual challenge of accurate electronic structure and enhanced sampling for complex catalytic systems.
• To provide a cost-effective method for computing kinetics in strongly correlated molecular systems.

Main Methods:

• Combining multiconfiguration pair-density functional theory (MC-PDFT) for accurate electronic structure calculations.
• Utilizing on-the-fly probability-enhanced sampling flooding (OPESf) to accelerate the sampling of reactive transitions.
• Applying the combined MC-PDFT-OPESf method to the Diels-Alder [4+2] cycloaddition reaction.

Main Results:

• The MC-PDFT-OPESf method accurately predicts reaction rates for the Diels-Alder reaction.
• The computed rates show agreement with experimental data.
• The approach achieves this accuracy at a significantly reduced computational cost compared to conventional unbiased *ab initio* methods.

Conclusions:

• MC-PDFT-OPESf is an efficient and accurate method for computing kinetics in systems with strong correlation.
• This approach offers a viable solution for studying complex catalytic reactions.
• The proposed method facilitates a deeper understanding and optimization of catalytic processes.