A Kohn–Sham study of CH4, C6H6, and O3 using functionals incorporating exact exchange

Abstract

Kohn–Sham density functional theory calculations are presented for CH4, C6H6, and O3 using popular exchange-correlation functionals based on the adiabatic connection method (ACM). The structure and harmonic vibrational frequencies of CH4 and C6H6 are described very well with the ACM functional. In particular, a very accurate description of CH vibrations is obtained, suggesting a possible resolution of this well-known deficiency of conventional functionals. In contrast, the application of ACM functionals to the energetics, structure, and harmonic frequencies of O3 yields results which are rather poor compared to conventional functionals. These observations appear to be closely related to the performance of Hartree–Fock theory for these systems.