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

摘要

A reactive laser ablation of graphite in a nitrogen atmosphere was investigated by optical emission analysis of the laser-induced plasma. Two emission bands of C_2 (d~3 product g -> a~3 product u, Swan band) and CN (B~2Σ~+ -> X~2Σ~+, Violet band) were observed. The vibrational and rotational temperatures of C_2 and CN molecules were deduced by simulation of the emission spectra. We examined the dependence of vibrational and rotational temperatures 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 molecules.