Evaluation and comparison of transition states with the HCTH98 and FT97 functionals

A series of seven transition states was examined using the new pure density functionals, Hamprecht–Cohen–Tozer–Handy 1998 (HCTH98) and Filatov–Thiel 1997 (FT97). Both HCTH98 and FT97 surpass older pure functionals in quality and compare favorably to hybrid functionals, exhibiting good geometries and frequencies. HCTH98 outperforms all of the pure and hybrid functionals regarding barrier-height calculations, whereas FT97 rivals hybrids in accuracy. Basis-set effects ranging from 6-31G(d) to aug-cc-pVTZ were investigated and determined to be minimal. The use of fitting basis sets to obtain third-order scaling had negligible effects.