Abstract: The(0001)plane of the high oriented pyrolytic graphite(HOPG)was directly ablated by pulsed laser, and the products were recorded by mass spectrometry in situ.It is found that the relative abundances of C₆₀, C₇₀and other larger fullerenes were related to the ablating time─the regularity of the HOPGstirface, which was imaged by scanning tunneling microscopy (STM).At the beginning of laser ablation, the(0001)plane contained enough six-membered rings, which mainly produced C₆₀and C₇₀.After laser ablation, many exposed platforms with no enough six-memberted rings, like amorphous carbon and aromatic compounds, were formed, which tended to form larger fullerenes.

Key words: C₆₀, Fullerenes, Laser ablation, HOPG, Six-membered ring plane