ELECTRON PROPAGATOR CALCULATIONS ON LINEAR AND BRANCHED CARBON CLUSTER DIANIONS

Electron propagator calculations have been performed on linear carbon cluster dianions from C72- to C102- and on branched C72-, C92-, and C112- structures which have a central, tricoordinate carbon bound to three branches with alternating long and short bonds. The more stable, branched isomer of C72- has a positive vertical ionization energy, but the linear form does not. While linear C 102- is stable with respect to electron loss, it is not possible to decide from these calculations whether linear C8 2- and Cp92- have the same property. There is evidence that better calculations would obtain bound C82- and C92- species. Vertical ionization energies of all branched dianions are positive. Feynman-Dyson amplitudes for dianion ionization energies display delocalized π bonding, with the two terminal carbons of the longest branches making the largest contributions. © 1995 American Institute of Physics.