A novel approach to elemental analysis by Laser Induced Breakdown Spectroscopy based on direct correlation between the electron impact excitation cross section and the optical emission intensity

摘要

In Laser Induced Plasma Spectroscopy (UPS) or Laser Induced Breakdown Spectroscopy (LIBS) the relation between recombining electrons and optical emission intensity has been studied in hydrogen and different metals targets. The role played by the electron impact excitation cross section on the temporal trend of emission lines has addressed and a methodology for the evaluation of the excitation cross sections by optical emission spectroscopy has been tested on several species including H I, Fe I, Ni I, Co I and Ti II. In connection with the theory drawn in this paper, the results show a good agreement with respect to theoretical ones. These results allow the direct linking of the emission intensity to the electronic excitation binary collision. The latter does not depend on experimental conditions and can be applied for elemental analysis. The use of estimated cross sections forms the basis for a different calibration free approach. LIBS elemental analysis on iron meteorites (to be considered as ternary alloys) and on a set of copper based alloys demonstrates the promising use of this analytical approach.