抄録
Laser ionization time-of-flight mass spectrometry has been used to probe neutral species produced by laser ablation of graphite at 266nm and 1064nm. Arrival time profiles of the neutral species were measured by changing delay times of postionization. C3 was the major species. The yields of C and C2 normalized to that of C3 at 266nm (0.4-0.75J/cm2) were 0.16-0.17 and 0.13-0.15, respectively. The yields of C and C2 at 1064nm (0.7-1.0J/cm2) were 0.03-0.05 and 0.02-0.03, respectively. Arrival velocity distributions with different most probable or center-of-mass velocities were observed depending on ablation laser wavelength and fluence. However, C, C2, and C3 showed similar arrival velocity distributions. We discuss the formation of C, C2, and C3 in terms of a direct ejection process from the graphite surface and a collisional process in the ablation plume.
