TY - CONF A1 - Gornushkin, Igor B. A1 - Shabanov, Sergej V. A1 - Völker, Tobias A1 - Kepes, Erik A1 - Wolsch, Gerd A1 - Baudelet, M. T1 - Molecule formation in calcium carbonate and calcium hydroxide libs plasmas: model and experiment N2 - Analysis of calcium hydrate and calcium carbonate samples and their mixtures is important for archeology, anthropology, and geology. Laser-induced plasma spectroscopy (LIBS) is a suitable tool for such the analysis as it allows for in- and on-line real time chemical assays. LIBS is inherently a technique for atomic analysis; however, since recently, it is also used for molecular analysis. The information attained by the latter is mainly related to “secondary” chemistry that deals with re-association of atoms and ions into molecules at long delay times (≥10 μs) after the initial breakdown. Even though the direct information about the initial molecular content in the target may be lost, the molecular analysis by LIBS can still be useful to assess the composition of samples. In this work, chemical reactions in laser induced plasmas (LIPs) created on calcium hydrate and calcium carbonate targets in argon are modeled and compared to experiment. The model is based on the assumption that all ionization processes and chemical reactions are at local thermodynamic equilibrium. A chemical composition of argon-calcium-oxygen and argon-calcium-hydrogen plasmas is studied as a function of plasma temperature and pressure. It is established that more than twenty simple and composite molecules and ions can be formed in the course of chemical reactions. The results are compared with those obtained by means of the equilibrium model based on the minimization of Gibbs free energy. T2 - SciX 2019 CY - Palm Springs, USA DA - 13.10.2019 KW - Plasma diagnostics KW - LIBS KW - Laser induced plasma KW - Plasma modeling PY - 2019 AN - OPUS4-49775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -