Ions in solution: density corrected density functional theory (DC-DFT).

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Standard density functional approximations (DFAs) often yield inaccurate results for odd-electron radical complexes.
• Self-interaction error is a primary cause of these inaccuracies in DFAs.
• Density corrected density functional theory (DC-DFT) offers a method to improve calculation accuracy.

Purpose of the Study:

• To discuss the identification of cases where DC-DFT provides significant improvements.
• To explore the general applicability of DC-DFT.
• To illustrate the impact of DC-DFT on the potential energy surfaces of radical complexes.

Main Methods:

• Calculation of potential energy surfaces for HO·Cl(-) and HO·H2O complexes.
• Comparison of results from various common approximate functionals with and without density correction.
• Assessment of the influence of implicit solvent on DC-DFT results.

Main Results:

• Standard approximations produced wrongly shaped potential energy surfaces and incorrect minima for the studied complexes.
• DC-DFT yielded almost identical, accurate shapes and minima compared to self-consistent calculations.
• The accuracy improvements from DC-DFT were maintained in the presence of implicit solvent.

Conclusions:

• DC-DFT effectively corrects errors in standard DFAs for radical complexes.
• The method provides reliable potential energy surfaces and minima, even with common approximate functionals.
• DC-DFT is a robust approach, applicable even under solvent effects.