Physical Processes in Optical Emission Spectroscopy

Different aspects of physical processes in optical emission spectroscopy are analyzed in equilibrium and non equilibrium conditions. A very simple but accurate method to calculate the partition function of atomic species based on the reduction of the energy level pattern to a three grouped levels system is introduced. Collisional-radiative models are illustrated with different examples emphasizing the coupling of the electron energy distribution function with excited states population and radiation. Finally, models including fluid dynamic equations to describe the LIBS plume expansion in both one and two space dimensions are discussed, showing that these methods can be used to qualitatively rationalize double pulse experiments and, to some extent, to reproduce experimental results.