Torsional potential of π-conjugated molecules using the localized Hartree–Fock Kohn–Sham exchange potential

Abstract

We have assessed the reliability of the localized Hartree–Fock (LHF) Kohn–Sham exchange potential for the description of the torsional potential of π-conjugated molecules. The LHF method is compared with other exchange-only energy functionals, as well as experiments and ab initio reference calculations for butadiene, biphenyl and bithiophene. Results indicate that the LHF method provides a good and system-independent description of the torsional potential of π-conjugated molecules and it is the only functional that can be improved by the addition of a correlation term. Using the Lee–Yang–Parr correlation functional very good agreement with reference data is found.