ONIOM meets : efficient, accurate, and robust multi-layer simulations across the periodic table

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Molecular Mechanics

Background:

• The computational treatment of large molecular structures is crucial in modern chemistry.
• Efficient quantum chemical methods are essential for sophisticated investigations.
• The ONIOM (Our own N-layered integrated molecular orbital and molecular mechanics) multi-layer scheme is a well-established approach.

Purpose of the Study:

• To implement the ONIOM scheme within the xtb semi-empirical program package.
• To apply this integrated method to challenging transition-metal complexes.
• To elucidate reaction energies, geometry optimizations, and solvation effects in large metal-organic systems.

Main Methods:

• Implementation of the ONIOM scheme into the xtb program.
• Application of GFNn-xTB and GFNn-FF methods within the ONIOM framework.
• Investigating metal-organic systems with up to several hundred atoms.

Main Results:

• The ONIOM-xtb implementation enables the study of large molecular systems.
• Accurate analysis of reaction energies, geometry optimizations, and solvation effects is achieved.
• Computational costs are significantly reduced for large-scale investigations.

Conclusions:

• An ONIOM-based combination of DFT, semi-empirical, and force-field methods is effective.
• This approach drastically reduces computational costs for large systems.
• The investigation of huge systems is enabled with minimal loss in accuracy.