Weak Noncovalent Interactions in Nonequilibrium Structures: How Good Are the Dispersion Corrections?

Area of Science:

• Computational chemistry
• Materials science

Background:

• Density functional theory (DFT) methods often struggle to accurately describe noncovalent interactions.
• Dispersion corrections are crucial for improving DFT accuracy, especially for van der Waals forces.

Purpose of the Study:

• To evaluate the performance of various dispersion corrections in density functional theory for describing noncovalent interactions in nonequilibrium structures.
• To identify which dispersion corrections are most reliable for challenging molecular geometries.

Main Methods:

• Testing common dispersion corrections (D-family, XDM, VV10, MBD) on acene and polyene dimers in eclipsed arrangements.
• Analyzing the accuracy of these corrections for systems far from their energy minima.

Main Results:

• Dispersion corrections relying on electron density information (VV10, MBD) performed well for nonequilibrium structures.
• Other dispersion correction methods showed increasing errors with system size.
• Nonequilibrium geometries are inadequately represented in the parameterization of many dispersion corrections.

Conclusions:

• VV10 and MBD corrections show potential for accurately modeling noncovalent interactions in challenging, nonequilibrium geometries.
• Current dispersion correction parameterizations may limit the accurate modeling of real-world systems and conditions.
• Further development is needed to improve the representation of nonequilibrium structures in dispersion corrections.