Anomalous Photofragmentation of Fullerene Doped in Silica Aerogel─Enhanced Formation of Odd-Numbered “Fullerene” Fragments
KONG Qing-Yu1,2, ZHAO Li1,2, ZHUANG Jun1,2, QIAN Shi-Xiong1,2, LI Yu-Fen1,2, WANG Jue3
1Department of Physics, Fudan University, Shanghai 200433
2State Key Joint Laboratory for Materials Modification by Laser, Ion and Electron Beams, Fudan University, Shanghai 200433
3Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092
Anomalous Photofragmentation of Fullerene Doped in Silica Aerogel─Enhanced Formation of Odd-Numbered “Fullerene” Fragments
KONG Qing-Yu1,2;ZHAO Li1,2;ZHUANG Jun1,2;QIAN Shi-Xiong1,2;LI Yu-Fen1,2;WANG Jue3
1Department of Physics, Fudan University, Shanghai 200433
2State Key Joint Laboratory for Materials Modification by Laser, Ion and Electron Beams, Fudan University, Shanghai 200433
3Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092
Abstract： Photofragmentation of fullerene-doped silica aerogels has been investigated by the excimer laser ablation reflectron time-of-flight mass spectrometric technique. Great enhancement in the formation of odd-numbered ‘fullerene’fragments has been observed in the negative ion channel for the chemically doped aerogel sample. Generally, odd-numbered species C57, C55, C53, C51 appeared in the mass spectra. Under optimal experimental conditions C55 can be even more intense than the neighboring even-numbered carbon clusters. In contrast, for the physically doped sample, just like pristine C60, only weak odd-numbered fragments were observed. In the positive-ion channel, the behaviour of all these samples is similar, no odd-numbered species was ever detected. A mechanism related to the interaction between the fullerene dopant and the silica aerogel host is suggested for the anomalous enhancement of the odd-numbered cluster formation. A preliminary discussion on the structures of the odd-numbered ‘fullerene’fragments is given.
2001, Vol. 18 
