ИСТИНА

Qualitative analysis with the use of atomic emission spectroscopy is essentially a task of recognition of analyzed sample spectra. Spectra recognition is usually performed with step-by-step identification of all elements, comparing their strongest lines (fingerprint) with the experimental spectrum. The identification of emission lines in the Laser-Induced Breakdown Spectrometry (LIBS) is a very difficult and time consuming task due to huge heterogeneity of laser plasma and strong matrix effect. Therefore, excitation conditions in mainly depend on a sample matrix, wavelength of the laser beam, external pressure, and others. For example, we cannot clearly assign the weak emission line in a spectrum of steels with the strong line of minor component or with the weak line of matrix elements (such as Fe, Cr, Ni). The elemental qualitative analysis of environmental objects, such as soils or rocks is even more difficult procedure. The problem is to assign each of the peaks with specific emission line of a certain element due to the strong superposition of emission lines in UV-VIS spectral range. We have applied another algorithm to identify emission lines in LIBS. The algorithm implemented by three parts: simulation of the set of spectra corresponding to different temperature (T) and electron density (Ne), searching the best correlated pair of model spectrum and experimental one and attributing the peaks with certain lines. In order to construct the model spectra we used the parameters of atomic and ionic lines, levels, the mechanisms of the broadening of spectral lines and the selected parameters of the spectrograph. We tried different weighting procedures for attribution of the peak with the certain line, involving the values of transition probabilities and closeness to the center of observed peak. Suggested approaches provide a fast and accurate recognition of the LIBS spectra of soils and steels.