INSTABILITY OF TETRAHEDRAL BONDING FOR THE C-100 MOLECULE

The diamond-interior C100 molecule has been studied with a local-densi ty-functional cluster method and found to be unstable with respect to a Jahn-Teller distortion. More seriously, the original diamondlike str ucture is unstable; the molecule spontaneously decomposes into an inne r C20 core trapped inside an outer C80 fullerenelike shell. In essence , tetrahedral bonding throughout the molecule gives rise to 60 danglin g bonds at the surface, which give way to 20 dangling bonds on the inn er C20 surface in the double-shell fullerene. As expected, hydrogen st abilizes the tetrahedral bonding in C100H60.