Generalized gradient approximation exchange energy functional with correct asymptotic behavior of the corresponding...

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Materials Science

Background:

• Generalized Gradient Approximation (GGA) functionals are widely used in computational chemistry.
• Accurate prediction of molecular properties requires functionals with correct asymptotic behavior.

Purpose of the Study:

• Develop and evaluate a new non-empirical exchange energy functional (CAP) with correct asymptotic behavior.
• Assess the performance of the CAP functional, particularly in combination with the PBE correlation functional (CAP-PBE).

Main Methods:

• Developed a new non-empirical exchange energy functional of the GGA type.
• Combined the new CAP exchange functional with the PBE correlation functional.
• Tested the CAP-PBE functional against standard datasets for various molecular properties.

Main Results:

• CAP-PBE demonstrates competitive accuracy for heats of formation, ionization potentials, electron affinities, and reaction barriers.
• CAP-PBE shows significant improvements in response functions, such as static and dynamic polarizabilities.
• Improvements are linked to enhanced highest occupied and lowest unoccupied molecular orbitals, not eigenvalue shifts.

Conclusions:

• The CAP-PBE functional is a promising development in GGA-type functionals.
• Its strength lies in accurately describing response properties, making it valuable for electronic structure calculations.
• Further research into the potential's behavior at intermediate distances could lead to even better functionals.