Laser induced plasmas at different nebulization conditions: Spatio-temporal distribution of emission signals and excitation temperatures

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy Vol. 170; p. 105906
• Main Authors: Méndez-López, C., Álvarez-García, R., Alvarez-Llamas, C., Fernández-Menéndez, L.J., González-Gago, C., Pisonero, J., Bordel, N.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.08.2020; Elsevier BV
• Subjects: Ablation; Decay; Emission analysis; Emission measurements; Excitation; Excitation temperatures; Fluorine; Laser induced breakdown spectroscopy (LIBS); Laser plasmas; Lasers; Molecular and atomic emission signals; Nebulization; Plasma; Plasma plume; Spatial distribution; Spatio-temporal distribution; Temporal distribution; Laser induced breakdown spectroscopy (LIBS); Nebulization; Spatio-temporal distribution; Excitation temperatures; Molecular and atomic emission signals; Plasma plume
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2020.105906

CaF emission measurements are currently employed for indirect determination of fluorine concentration in solid samples using LIBS. This approach provides more sensitivity and improved limits of detection in comparison to the use of F atomic emission lines in the IR region, for quantitative purposes. Moreover, in Ca-free samples, the simultaneous nebulization of a Ca-containing solution during LIBS analysis was successfully proposed as a method to obtain the CaF emission, and indirectly determine the F concentration. Nevertheless, further insights are still required to understand the interaction of the laser-induced plasma with the nebulized solution. Therefore, in this work, the general effects of different nebulization conditions on a laser induced plasma are investigated in terms of variations in the plasma plume shapes, emission intensities and excitation temperatures. In particular, four different conditions are evaluated using Cu matrix as a model sample (i.e. non-nebulized sample, Ar nebulization, water nebulization and Ca-containing solution nebulization). Significant changes were shown under the Ca-solution nebulization, including a modification of the intensity decays of the Cu lines, lower average Cu excitation temperatures independently of the temporal window investigated, increased ablation rates, a huge asymmetry of the excited species in the plasma plume, and a partial detachment of the plume. [Display omitted] •Physical characterization of a “nebulized” laser induced plasma.•Alteration of LIP plume shape with a detachment event seen with Ca-nebulization.•Effect on the spatial distribution of excitation temperatures.•Changes on ablation rates and craters profiles due to the aerosol droplets.