04/00136 Hydrogen storage behavior of C 116 system - AM1 treatment : Türker, L. International Journal of Hydrogen Energy, 2003, 28, (10), 1115–1119.

Abstract

Are the semiempirical methods still reliable for large fullerenes? To answer this question, in this paper, the semiempirical AM1, PM3, MNDO, and tight-binding calculations were performed on the candidate isomers selected from the complete sets of isolated-pentagon-rule isomers of C116–C120 based on the second generation reactive empirical bond order potential. To assess the reliability of these semiempirical methods and predict the ground-state structures more accurately, the density functional theory calculations at the B3LYP/6-31G(d)//B3LYP/3-21G level of theory were also carried out on the top 20 low-energy candidates from each semiempirical method. It was found that the tight-binding potential gives a good agreement for the prediction of the relative energies when compared with the B3LYP/6-31G∗ results, while AM1, PM3, and MNDO methods behave badly. Furthermore, we also investigated the structures of the B3LYP/6-31G∗ low-energy isomers for C116–C120 to understand the relationship between the stability and some structural factors.