Density functional theory and hydrogen bonds: are we there yet?

Area of Science:

• Computational Chemistry
• Quantum Chemistry

Background:

• Hydrogen bonds are crucial in biological systems.
• Density functional theory (DFT) is increasingly used for molecular interactions.
• Accurate description of dispersion forces is vital for DFT accuracy.

Purpose of the Study:

• To evaluate DFT's performance in describing hydrogen-bonded interactions.
• To assess the impact of dispersion corrections on DFT accuracy.
• To compare DFT methods with MP2 for hydrogen-bonded systems.

Main Methods:

• Investigated DFT functionals with and without dispersion corrections.
• Analyzed small and large molecular complexes with hydrogen bonds.
• Compared DFT results against MP2 calculations.

Main Results:

• Dispersion corrections in DFT led to significant errors for small complexes dominated by electrostatics.
• For larger systems, dispersion corrections improved DFT's accuracy for hydrogen bonds.
• Most tested DFT functionals were less accurate than MP2, except for DSD-PBEP86 (without dispersion).

Conclusions:

• DFT's suitability for hydrogen bonds depends on system size and the inclusion of dispersion.
• Careful selection of DFT functionals and dispersion corrections is necessary for accurate biological modeling.
• MP2 remains a benchmark for high accuracy in describing these interactions.