Computational evidence for a new C84 isomer

Endohedral chemical shifts of all isolated pentagon isomers of C76 and C78, as well as those of the most stable isolated pentagon isomers of C84, have been computed at the GIAO-SCF/DZP level using DFT optimized geometries (Becke88-perdew86/3-21G). The theoretical data support tentative assignments of recent experimental σ(3He) NMR data to the major components in a partly separated, 3He labeled mixture. The identification of at least one new fullerene isomer, C84D2d(4), is suggested, based on the endohedral chemical shift of −25.0 ppm (calc.) versus −24.4 ppm (exp.).