Determination of transition probabilities by laser-induced breakdown spectroscopy with curve-of-growth measurements

摘要

A method for the measurement of transition probabilities using laser-induced plasmas as spectroscopic sources is presented. To check its validity, the method is applied to 19 Ni II lines, most of them with known A_(ki) values. The method is based on the measurement of curves of growth using samples with varying concentrations of the element of interest (here, nickel-copper alloys with nickel contents in the range 0.11-27at%). The plasma is characterized by a reduced set of parameters, obtained by usual techniques (Boltzmann plot and Stark shift) combined with the curve-of-growth methodology. The transition probabilities are determined by fitting experimental curves of growth to calculations based on the plasma parameters. The use of curves of growth allows eliminating the systematic error due to the self-absorption in the measurement of transition probabilities, and is applicable to intense as well as very weak lines.