A COMPARISON OF THE ACCURACY OF DIFFERENT FUNCTIONALS

The errors in the computed geometries, zero-point energies, and atomiz ation energies of molecules containing only first and second row atoms are compared for several levels of theory, including Hartree-Fock, se cond-order Moller-Plesset perturbation theory (MP2), and density funct ional theory (DFT) using five different functionals, including two hyb rid functionals. The 6-31G and 6-311 + G(3df, 2p) basis sets are used . Overall, the B3LYP hybrid functional yields the best results.