A COMPARATIVE-STUDY OF AB-INITIO SCF-CI AND DFT - EXAMPLE OF SMALL BORON CLUSTERS

A linear search for minima on potential energy surfaces based on analytical gradient methods and the determination of binding energies of small boron clusters B-n (n = 2-14) have been made using the ab initio Hartree-Fock and configuration interaction quantum chemical methods as well as by means of density functional theory at the local spin density and non-local corrections to the exchange-correlation levels of theory. The final Hartree-Fock optimized topologies of the neutral boron clusters are identical with those derived with the local spin density approximation. The most stable boron clusters have convex or quasiplanar structures. The convex clusters seem to be segments of the surface of a sphere. The capabilities of both methods for such cluster systems are illustrated.