Multistructural microiteration combined with QM/MM-ONIOM electrostatic embedding

Area of Science:

• Computational chemistry
• Quantum mechanics/molecular mechanics (QM/MM) methods

Background:

• The ONIOM method is widely used for QM/MM calculations.
• Existing ONIOM formulations include mechanical embedding (ME) and electrostatic embedding (EE).
• Multistructural microiteration (MSM) accounts for multiple surrounding structures in QM/MM calculations.

Purpose of the Study:

• To combine MSM with the EE scheme of QM/MM-ONIOM.
• To develop an extended MSM-EE formulation for improved accuracy.
• To evaluate the performance of MSM-EE against other QM/MM methods.

Main Methods:

• Extended the original formulation of QM/MM-ONIOM EE for ME.
• Developed MSM-EE to include polarization effects from surrounding structures.
• Applied MSM-EE, ONIOM-ME, ONIOM-EE, and MSM-ME to three chemical processes.

Main Results:

• MSM-EE accurately predicted reaction barriers and energies for tested chemical processes.
• Results from MSM-EE closely matched experimental values.
• Computational costs for MSM-EE were comparable to other tested methods.

Conclusions:

• MSM-EE is a robust and efficient QM/MM method for studying chemical reactions.
• The developed MSM-EE approach enhances the accuracy of ONIOM calculations.
• This method provides a valuable tool for theoretical chemistry research.