A performance comparison between the CEP effective core potential/triple-split basis set approach and an all-electron computational method with emphasis on small Ti and V alkoxide complexes

摘要

The structures of 30 neutral and positively charged small clusters were optimized and a number of hypothetical reaction pathways were investigated to compare the performance of the B3LYP-CEP-121 G(d) Effective Core Potential/triple-spilt basis set method (ECP, method 1) and the B3LYP/6-311 G(d) approach (method 2) for geometry optimizations. In addition, single point calculations at the B3LYP/CEP-121+G(d,p) (on geometries optimized by method 1) and at the B3LYP/6-311+G(d,p) (on optimized structures from methods 1 and 2) levels were also carried out. The augmented CEP-121G scheme is roughly 1.4 to 2.0 times compoutationally cheaper than full electron calculations, and is able to reproduce structures, infrared frequencies, thermochemical parameters and dipole moments predicted by the all-electron baiss set employed in this study.From a practical viewpoint, the rsults confirm that ECPs can be used in combination with density functional mthods, despite the face that th eformer are typically generated via a Hartree-Fock approach.