Berlin 2001 – scientific programme
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MO: Molekülphysik
MO 2: Clusters I: Metal Clusters (joint session A and MO)
MO 2.12: Talk
Monday, April 2, 2001, 18:30–18:45, H1012
Production of Carbon Clusters by Laser Ablation of Graphite and Polymers in Vacuum — •Kanji Shibagaki, Noriharu Takada, Koichi Sasaki, and Kiyoshi Kadota — Department of Electronics, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
Time-of-flight mass spectrometry has been used for detection of ion species produced by laser ablation of graphite and polymers: polyethylene, polypropylene, and polytetrafluoroethylene. Mass spectra of positive and negative cluster ions were observed as a function of delay time between the irradiation of the laser pulse and acceleration of ions. As a result, it has been found that the sizes of carbon clusters and their hydrogenated or fluorinated species have significant temporal evolution with the increase in the delay time. This fact indicates that clustering reactions progress even in vacuum without ambient gas. The mechanism of clustering is considered to be reactions among various neutral species and their ions containing carbon and hydrogen or fluorine atoms in the laser ablation plume. In addition, from the signal intensities of negative carbon cluster ions and their hydrogenated species observed for polymer targets, it has been suggested that even carbon clusters are hydrogenated more effectively than odd ones. It has been shown by the present work that even carbon clusters react selectively with ablated H atoms as well as H2 molecules.
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