A study of small systems containing H and O atoms using nonlocal functionals: comparisons withab initio and experiment

Abstract

Structures and energies have been calculated for HO, H2O, O2, HO2, H2O2, and O3 molecules using the nonlocal functionals PW, PW91, B-P86, and B-LYP with the goal of obtaining their atomization energies. Results were compared with those from highly correlated methods and experiment. It was found that all nonlocal functionals perform similarly to or better than correlated methods MP4 and QCI (using relatively equivalent basis sets). All nonlocal energies were self-consistently calculated using the optimized geometries for each functional. None of the results contain any empirical correction except those inherent to some of the functionals. Increasing the size of the basis set when using the nonlocal functionals does not lead to any significant improvement of the energies and surprisingly it worsens the results for one of the functionals. © 1994 John Wiley & Sons, Inc.