Reactive laser ablation of graphite in a nitrogen atmosphere: optical emission studies

A reactive laser ablation of graphite in a nitrogen atmosphere was investig ated by optical emission analysis of the laser-induced plasma. Two emission bands of C-2 (d(3)Pi(g) --> a(3)Pi(u), Swan band) and CN (B(2)Sigma(+) --> X(2)Sigma(+), Violet band) were observed. The vibrational and rotational t emperatures of C-2 and CN molecules were deduced by simulation of the emiss ion spectra. We examined the dependence of vibrational and rotational tempe ratures on the laser fluence and distance from the target to elucidate the expansion dynamics of the plume and formation mechanisms of C-2 and CN mole cules. (C) 1999 Elsevier Science B.V. All rights reserved.