A COMPARATIVE-STUDY OF DENSITY FUNCTIONAL MODELS TO ESTIMATE MOLECULAR ATOMIZATION ENERGIES

In the present study the molecular atomization energies have been computed with some of the recent density functionals and with a semiempirical model developed in the IBM laboratory. In particular, the Lie-Clementi (LC), the Colle-Salvetti (CS), the Gunnarson-Lundqvist (GL), the Vosko, Wilk, and Nusair (VWN), the Perdew-Zunger (PZ), the Becke (B), and the Lee, Yang, and Parr (LYP) functionals have been considered. For GL and VWN the self-interaction correction of Stoll, Pavlidou, and Preuss (SPP) has been included. For the PZ the gradient correction of Perdew has been included. For the LYP a new and simpler form as proposed by Michlich et al. has been implemented. More than 50 small to fairly large molecules have been chosen at test cases. The results obtained with the present semiempirical model are gratifying and indicate that further improvement and calibration is still possible. From the computed data it is concluded that the density functionals in most cases do provide a pragmatic solution to the determination molecular atomization energy. © 1990 American Institute of Physics.