Strong-field ionization of CH3Cl using femtosecond laser pulses, and the subsequent two-body dissociation of CH3Cl2+ along Hn+ (n =1-3) and HCl+ forming pathways, have been experimentally studied in a home-built...
Stark broadening parameters have been estimated for resonant lines of Al(I) using time resolved measurements. The relation between the various emission line characteristics at different phases of opacity have been utilized to obtain the value of plasma temperature and Stark width parameters from the experimental data. The observed value of the center line intensity and Lorentzian component of the line width are compared against a simulated value of these parameters for optically thin case. The plasma temperature and Stark broadening parameters are obtained for the best fit condition by matching the experimentally observed and the simulated values of intensity and line widths. The time resolved measurements result in much better estimates for Stark parameters by allowing multiple points for fitting keeping the number of variables limited. The Stark shift parameters are also obtained from the slope of the plot of observed central wavelength shifts versus observed electron number density which is measured as a function of time. Hence, a method utilizing multiple-time observation data to obtain the Stark broadening parameters for lines showing self-absorption has been demonstrated.
The present work aims to understand the signal enhancement observed in nanoparticle-enhanced LIBS (NELIBS) due to changes in the plasma parameters as a result of improved atomization and excitation. A systematic study on signal enhancements during NELIBS using simultaneous spectroscopy and imaging is investigated by varying the experimental parameters like particle size and laser fluence. We have observed similar enhancements in spectroscopy and imaging channels regardless of nanoparticle(NP) size at different laser fluences. Although the plume size in NELIBS was marginally more prominent than the LIBS at the same laser fluence, the corresponding intensity in NELIBS is significantly higher. This agrees with the hypothesis of efficient atomization and excitation of plasma in the case of NELIBS. Therefore, we performed a sensitivity analysis using simulated LIBS signal to understand changes in experimentally observable plasma parameters (excitation temperature and electron number density) on signal enhancement. We have shown that the enhancements in the emission intensities of typically one order of magnitude can be explained as a result of the change in electron number density and plasma temperature. A comparison of the expected enhancement due to this change with experimental observation for a Cu I line is also presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.