TY - CONF A1 - Gornushkin, Igor B. T1 - Modeling chemical reactions in laser induced plasmas N2 - Under the assumption of local thermal equilibrium, a numerical algorithm is proposed to find the equation of state for laser-induced plasmas (LIPs) in which chemical reactions are permitted in addition to ionization processes. The Coulomb interaction in plasma is accounted for by the Debye–Hückel method. The algorithm is used to calculate the equation of state for LIPs containing carbon, silicon, calcium, chlorine, nitrogen, and argon. The equilibrium reaction constants are calculated using the latest experimental and ab initio data of spectroscopic constants for the molecules N2, C2, Si2, CN, Cl2, SiN, SiC, CaCl, CaCl2 and their positive and (if existed) negative ions. The algorithm is incorporated into a fluid dynamic numerical model based on the Navier–Stokes equations describing an expansion of LIP plumes into an ambient gas. The dynamics of LIP plumes obtained by the ablation of SiC, CaCl2, solid silicon, or solid carbon in an ambient gas containing N2 and Ar is simulated to study formation of molecules and molecular ions. A particular attention is paid to formation of anions Cl−, Cl2−, Si2−, C2−, CN−, and SiN− in LIPs. T2 - Winter Plasma Conference, January 8-13 2016 CY - Tucson, USA DA - 08.01.2016 KW - Plasma KW - Plasma modeling PY - 2016 AN - OPUS4-38774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Diagnostics and modeling of laser induced plasma in relation to current needs of spectrochemical analysis N2 - The short report on computer modeling and diagnostics of laser induced plasmas T2 - Winter Plasma Conference CY - Tucson, USA DA - 08.01.2016 KW - Plasma diagnostics KW - Laser induced plasma KW - LIBS KW - Plasma modeling PY - 2016 AN - OPUS4-38773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Modeling and diagnostics of laser induced plasma for needs of spectrochemical analysis N2 - Two topics will be addressed: (1) calibration-free LIBS based on Monte Carlo spectral optimization and (2) insight into the possibility of simultaneous elemental and molecular analysis by LIBS. Both topics heavily rely on modeling of laser induced plasma and are closely connected to experiment. In Monte Carlo LIBS (MC LIBS), concentrations are found by fitting model-generated synthetic spectra to experimental spectra. The model of a static uniform isothermal plasma in local thermodynamic equilibrium is employed. Many configurations of plasma parameters and their corresponding spectra are simultaneously generated using a graphic processing unit (GPU). Using the GPU allows for the reduction of computational time down to several minutes for one experimental spectrum that presents the significant progress in comparison with earlier versions of MC LIBS. The method is tested by analyzing industrial oxides containing various concentrations of CaO, Fe2O3, MgO, and TiO2. The agreement within several percent between found and certified concentrations is achieved. Next, a newly developed collisional-dominated model of a laser induced plasma is introduced. The model includes the coupled Navier-Stokes, state, radiative transfer, and material transport equations and incorporates plasma chemistry through the equilibrium approach based on the use of atomic and molecular partition functions. Simple chemical systems are modeled including ablation of Si and C in N2 and Ar atmospheres.The model is used to study evolution of number densities of atomic and molecular species in the expanding plasma plume. The distribution is compared to experimental observations obtained by optical imaging and tomography. To further verify the model, dynamic plasma T2 - FLAMN 2016 CY - St. Petersburg, Russia DA - 27.06.2016 KW - Plasma diagnostics KW - Laser induced plasma KW - LIBS KW - Plasma modeling PY - 2016 AN - OPUS4-38775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Hydrodynamic model of laser induced plasma including equilibrium chemistry N2 - Hydrodynamic model of laser induced plasma including plasma chemistry T2 - 6.07.2017, ITMO University, St. Petersburg, Russia CY - ITMO University, St. Petersburg, Russia DA - 5.07.2017 KW - Plasma KW - LIBS KW - Plasma modeling PY - 2017 AN - OPUS4-42294 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Predicting molecules in laser induced plasma based on equilibrium plasma model N2 - New development in modeling reactive flows in laser induced plasma T2 - 09.10.2017, SciX, Reno, NV, USA CY - Reno, NV, USA DA - 08.10.2017 KW - Laser induced plasma KW - LIBS KW - Plasma modeling PY - 2017 AN - OPUS4-42295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Calibration-free Monte Carlo method for laser induced breakdown spectroscopy N2 - Calibration-free LIBS via Monte Carlo approach T2 - 8-14.10.2017 SciX, Reno, NV, USA CY - Reno, NV, USA DA - 7.10.2016 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics KW - Lasers PY - 2017 AN - OPUS4-42298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Calibration-free Monte Carlo method for laser induced breakdown spectroscopy N2 - Calibration-free LIBS by Monte Carlo simulation of plasma spectra T2 - April 26 2017, Johannes Kepler University, Linz, Austria CY - Johannes Kepler University, Linz, Austria DA - 26.04.2017 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2017 AN - OPUS4-42288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Model of stimulated emission in aluminium laser-induced plasma produced by resonance pumping N2 - Model of lasing effect in resonantly pumped aluminum laser induced plasma T2 - EMS LIBS CY - Pisa, Italy DA - 11.06.2017 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2017 AN - OPUS4-42292 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Improved algorithm for calibration-free laser induced breakdown spectroscopy N2 - An improved algorithm for calibration-free laser induced breakdown spectroscopy (CF LIBS) will be presented which includes several novel features in comparison with previously proposed similar algorithms. In particular, it allows using spectral lines with arbitrary optical thickness for the construction of Saha-Boltzmann plots, retrieves the absorption path length (plasma diameter) directly from a spectrum, replaces the Lorentzian line profile function by the Voigt function, and allows for self-absorption correction using pre-calculated and tabulated data rather than approximating functions. The tabulated data embody the solutions of the radiative transfer equation for numerous combinations of optical thicknesses and line widths. The algorithm is thoroughly verified using synthetic spectra. T2 - LIBS 2018 at SciX 2018 CY - Atlanta, GA, USA DA - 21.10.2018 KW - Plasma diagnostics KW - Laser induced plasma KW - LIBS KW - Plasma modeling PY - 2018 AN - OPUS4-46930 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Improved algorithm for calibration-free laser induced breakdown spectroscopy N2 - An improved algorithm for calibration-free laser induced breakdown spectroscopy (CF LIBS) is presented which includes several novel features in comparison with previously proposed similar algorithms. In particular, it allows using spectral lines with arbitrary optical thickness for the construction of Saha-Boltzmann plots, retrieves the absorption path length (plasma diameter) directly from a spectrum, replaces the Lorentzian line profile function by the Voigt function, and allows for self-absorption correction using pre-calculated and tabulated data rather than approximating functions. The tabulated data embody the solutions of the radiative transfer equation for numerous combinations of optical thicknesses and line widths. The algorithm is thoroughly verified with synthetic spectra. T2 - 14TH European Workshop on Laser Ablation 2018 (EWLA2018) CY - Pau, France DA - June 26 - 29, 2018 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics KW - Calibration free LIBS PY - 2018 AN - OPUS4-45343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -