ACCURATE DENSITY-FUNCTIONAL CALCULATIONS ON LARGE SYSTEMS

The theoretical underpinnings of the linear combination of Gaussian-ty pe orbitals (LCGTO) calculations of the density functional (DF) energy of molecules and clusters are described. The generating function for three-center integrals of arbitrary angular momenta is given in the so lid-spherical-harmonic basis. Variational fitting is described and its accuracy tested. The LCGTO-DF method is used to address questions rel ated to the problem of how it is that the methods of cluster science, i.e., high-energy beams or currents, can be used to make C-60 in bulk quantities. In particular, it is shown that C-60 is neither especially stable nor is it the only large, stable, perfectly round, approximate ly sp(2) carbon molecule. (C) 1996 John Wiley & Sons, Inc.