材料期刊网

Standard heats of formation (Delta H(f)(0)) calculated at B3LYP/6-31G(d) for 114 isolated Pentagon rule fullerenes were reproduced within 4.2 kcal/mol on the basis of 24 pentagon-centered motifs. With the use of a C30-capped (5,5) single-walled carbon nanotube as test molecule, it is found that (i) both hexagon- and Pentagon-centered motifs can be employed to estimate the A,Ho of fullerenes, while the latter gives better results for large fullerenes; and (ii) with the consideration of nonplanar strain energy, the estimated results of Delta H(f)(0) can be further improved. The estimation scheme of pentagon-centered motifs can serve as a rapid prescreening tool for viable isomers of large fullerenes and is expected to be equally valuable for carbon nanotubes.