MAGNETIC-FIELD ENHANCED GROWTH OF CARBON CLUSTER IONS IN THE LASER-ABLATION PLUME OF GRAPHITE

Time-of-flight mass spectrometric studies were carried out on neutral and positive ion clusters, composed of up to twenty carbon atoms, prod uced by Nd:YAG laser ablation of graphite in the presence of magnetic fields in the range of 0.03-0.10 T. The growth of larger carbon cluste r ions with C-11(+) dominance in the laser-ionized ablation plume of g raphite was found to be enhanced by the magnetic fields. We believe th at an enhancement of ion-neutral reactions due to an increase of ionic species, resulting from collisional ionization of neutral species thr ough a confinement of electrons, leads to the growth of larger carbon cluster ions.