CHARACTERIZATION OF PARTICULATES ACCOMPANYING LASER-ABLATION OF NANO3

We present observations of submicrometer- to micrometer-sized particle s generated by high-fluence (greater than or equal to 10 J/cm(2)) 248- nm laser ablation of single-crystal NaNO3, in vacuum and at atmospheri c pressure, Small particles (50-200 nm in diameter) are ejected by hyd rodynamic sputtering, Larger particles (1-20 mu m in diameter) rare pr oduced by cavitation and spallation in the melt, Many particles formed in air carry electric charge, with roughly equal numbers of positivel y and negatively charged particles, The particle composition is consis tent with substantial nitrate decomposition, The implications of these observations with respect to laser-based chemical analysis are discus sed.