Method for measurement of transition probabilities by laser-induced breakdown spectroscopy based on CSigma graphs–Application to Ca II spectral lines

Abstract

We propose a method for determination of transition probabilities by laser-induced breakdown spectroscopy that avoids the error due to self-absorption. The method relies on CSigma graphs, a generalization of curves of growth which allows including several lines of various elements in the same ionization state. CSigma graphs are constructed including reference lines of an emitting species with well-known transition probabilities, together with the lines of interest, both in the same ionization state. The samples are fused glass disks prepared from small concentrations of compounds. When the method is applied, the concentration of the element of interest in the sample must be controlled to avoid the failure of the homogeneous plasma model. To test the method, the transition probabilities of 9 Ca II lines arising from the 4d, 5s, 5d and 6s configurations are measured using Fe II reference lines. The data for 5 of the studied lines, mainly from the 5d and 6s configurations, had not been measured previously.

Laser-Induced Breakdown Spectroscopy for Determination of Spectral Fundamental Parameters

“…This idea is at the basis of the curve-of-growth method [55][56][57] and its variations, as the C-sigma method, introduced by Aragon and Aguilera in 2014 [58,59] and recently improved by Safi et al [60].…”

Quantitative analysis by laser-induced breakdown spectroscopy based on generalized curves of growth

“…In a recent work [25], they have been used for measurement of transition probabilities. In the present work, Cσ graphs are used for two purposes: a previous step of characterization of the plasma and the LIBS system using a sample with known concentration and a later stage of analysis, in which the concentration C is used as a fitting parameter.…”

Measured oscillator strengths in singly ionized molybdenum

“…Regarding electron density, it was obtained from the Stark broadening of the H line, as done previously [4,38]. The resulting electron density was of 2.5 0.…”

“…Calculations and measurements of atomic data are necessary in many areas. Thus, an active line of research can be seen nowadays with regard to the determination of these parameters [1][2][3][4]. These studies range from atomic physics [5][6][7], to astronomy [8][9][10] or fusion [11,12] and data compilation of energy levels [13], oscillator strengths [14], radiative lifetimes [15] and line profiling [16].…”