EMISSION-SPECTROSCOPY OF A CARBON PLASMA FORMED BY LASER-ABLATION OF GRAPHITE - I - ABLATION BY XECL LASER-RADIATION

The method of time-resolved emission spectroscopy was used to investig ate the luminescence emitted by a carbon plasma plume formed as a resu lt of vacuum ablation of graphite by XeCl laser radiation. It was foun d that in the course of emission from the plasma the spectrum of this luminescence changed drastically and, at laser radiation energy densit ies Phi = 4-5 J cm(-1), the main contribution came from the emission b y C+ ions and C-2 radicals. The emission kinetics depended on the exci tation conditions and it also varied from one part to another of the p lasma plume. A method was developed for computer simulation of the spe ctra of C-2 radicals, which made it possible to determine the plasma v ibrational and rotational temperatures (T-rot and T-vib) from the reco rded luminescence spectra of these radicals, and also to study tempora l evolution of these temperatures. During the emission time the charac teristic temperatures of C-2 radicals were found to vary within wide l imits: T-vib = 2500-12 000 K, T-rot = 1500-10 000 K.