Formation of hydrogen-capped polyynes by laser ablation of graphite particles suspended in solution

Laser ablation of graphite particles suspended in benzene, toluene, or hexane solution has been studied using a Nd:YAG laser (355, 532, and 1064 nm). Product analyses using HPLC coupled with UV and visible absorption spectroscopy and GC/MS showed that linear hydrogen-capped polyynes (CnH2: n=10, 12, 14, and 16) were formed in benzene and toluene, while those of n=8, 10, 12, and 14 were produced in hexane. The formation rates of polyynes increased with increasing particle concentration from 0.5 to 4 mg/ml, then decreased above that until 10 mg/ml. The formation rates of polyynes decreased with increasing wavelength of the Nd:YAG laser, 355 nm>532 nm>1064 nm.