Experimental and computational studies of heterofullerenes

External doping of fullerenes C-60 and C-70 with heteroatoms is performed in a low pressure condensation cell, through the mixing of a vapor of doping material with a vapor made of preformed fullerenes. Mass spectrometric investigations of the resulting cluster distributions of C60Mx and C70Mx clusters are carried out for M = {Fe, Co, Ni, Rh, Ir and Si}. Further laser induced photofragmentation of these C60Mx and C(70)M(x)precursor clusters leads to the production of in-cage doped heterofullerenes with composition C59-2nM and C69-2nM We complement our study with ab-initio calculations of the geometrical and electronic structure of C59Si and C58Si2, obtained within density functional theory by relaxing self-consistently the structures to the local minima. (C) 1999 Acta Metallurgica Inc.