Chlorine--benzene complexes--the reliability of density functionals for non-covalent radical complexes.

Area of Science:

• Computational Chemistry
• Chemical Physics
• Quantum Chemistry

Background:

• The structure of the chlorine atom-benzene complex has been debated for over 50 years.
• Understanding non-covalent interactions is crucial in chemistry and physics.

Purpose of the Study:

• To reexamine the structure and energetics of the chlorine atom-benzene complex.
• To compare new density functional methods with standard DFT and composite methods.

Main Methods:

• Utilized new density functional methods designed for non-covalent complexes.
• Compared results with standard Density Functional Theory (DFT) and high-accuracy composite methods.

Main Results:

• The B3LYP functional failed to identify key stationary points found by other methods.
• The eta(1)-sigma complex was found to be more stable than the eta(1)-pi complex.
• Results contradict some previous computational studies.

Conclusions:

• Careful selection of computational methods is essential for studying non-covalent radical systems.
• The eta(1)-sigma complex is likely the more stable structure for chlorine atom-benzene.