Abstract: MATH/CHEM/COMP 2002, Dubrovnik,
June 2429, 2002

Topology, connectivity and electronic structure of C and B cages and the corresponding nanotubes Frederik E. Leys^{1}, Claudio Amovilli^{2}, and Norman H. March^{1} ^{1}Department
of Physics, University of Antwerp (RUCA), Groenenborgerlaan 171, B2020
Antwerp, Belgium ^{2}Dipartimento di Chimica e Chimica Industriale, Universita di Pisa, Via Risorgimento 35, 56126 Pisa, Italy After a brief discussion of the relation of curvature introduced into an originally planar graphitic fragment to pentagonal 'defects' such as are present in buckminsterfullerene, the oneto one correspondence between the geometry of B cages and C cage structures will be emphasized. A study of nanotubes will then be introduced by presenting a solution of the freeelectron network approach for a 'model boron' planar lattice with local coordination number 6. In particular the dispersion relation E(k) for the Pielectron bands, together with the corresponding electronic density of states will be exhibited. Finally heterostructures, such as BN cages and fluorinated buckminsterfullerene, will be briefly treated, the new feature here being electronegativity difference. 