In the present work, we report on the analysis of archaeological metal artefacts from Late Bronze Age, performed by means of Laser Induced Breakdown Spectroscopy (LIBS). The experiment was carried out at ambient air and at 1064 nm of a Nd:YAG laser with pulse durations of 10 ns and energy of 10 mJ. The analytical information obtained by LIBS spectra was used for qualitative determination of the elements in the material used for manufacturing of the investigated objects. Quantitative estimation of the elemental concentration of tin and lead in the bulk of the samples was done after generating calibration curves for a set of four standard samples with a wide range of tin and lead concentrations and with similar matrix composition. The preliminary results of the qualitative and the quantitative analyses gave indications about the manufacturing process of the investigated objects and for their provenance as well.
Radiative lifetimes of 17 excited states in Zr I, in the energy interval 29000 - 40974 cm-1, have been investigated using
the Time-Resolved Laser-Induced Fluorescence (TR-LIF) method. The levels belong to the 4d25s5p, 4d35p and 4d5s25p
electronic configurations were excited in a single - step process from levels belonging to the ground 4p25s2 a 3F or to
low-lying 4p25s2 a 3P, a 5F terms. For 14 levels, the lifetimes have been measured for the first time. Experimental results
are compared with theoretical calculations performed with a multiconfigurational relativistic Hartree-Fock method
including core polarization effects.
Experimental branching fractions for laser lines arising from excited states of 5d97s configuration of Au II have been determined by application of Laser Induced Breakdown Spectroscopy (LIBS). The experimental relative transition probabilities were converted into an absolute scale using theoretical values for the radiative lifetimes of the corresponding states, calculated in this work. Transition probabilities and radiative lifetimes have been determined by a relativistic Hartree - Fock method taking configuration interaction and core-polarization effects into account. A comparison of the present results with the available theoretical values has been made and shows a reasonable agreement although discrepancies are observed between theory and experiment for some transitions.
Experimental transition probabilities for lines arising from 4d9 6s, 4d9 5d configurations of Ag II spectrum and from 3d9 4d configuration of CuII spectrum were determined from measurements of emission-line intensities in a laser produced plasma. Theoretical calculations of the transition probabilities of these lines were made by HF method with relativistic effects and core polarization taking into account. Absolute transition probabilites were obtained by measured branching ratio and theoretical and data for radiative lifetimes. A comparison of the present results with the available theoretical and experimental values was made.
Laser Induced Breakdown Spectroscopy (LIBS) is a one of the successfully used technique for measuring experimental atomic and ionic transition probabilities. This is due to the excitation procedure easily provides highly ionised species and neutral atoms. Nevertheless, its range also extends to another applications such as the industry or in astrophysics. In this work, we explain a specific experimental set-up -consist of fomred by a Nd:YAG laser and grating monochromator coupled with a time-resolved optical multichannel analyser. The employment of the time and spatial spectroscopy in a laser produced plasma for obtaining transition probabilities is also described. From the laser produced plasmas it is also possible to determine some of their properties such as the temperature or the composition. Besides, due to the high emission and temperature, it can be proved the existence of Local Thermodynamic Equilibrium allows determination of absolute values for the transition probabilities and the evaluation of some characteristics such as the self-absorption. The experimental data treatment for obtaining the transition probabilities and the different plasma properties that can be derived was explained.
Radiative lifetimes of 1 1 levels in Cd I belonging to the 5s5p 1po1 and 5snd 3D1,2(n=6-9) and 5sns 3S1 (n=7,8) series, and of 5 levels of Cd II belonging to the 4d105p 2po1/2,3/2, 4d106s 2S1/2, and 4d105d 2D3/2,5/2 configurations were measured using the time-resolved laser-induced fluorescence technique. Free neutral and singly ionized cadmium were generated by laser ablation. Single- or two-step excitation processes were used to populate the levels under study. Transition probabilities and oscillator strengths for Cd I and Cd II transitions were also deduced by combining the experimental lifetimes and theoretical branching fractions obtained in multiconfigurational relativistic Hartree-Fock calculations, taking core-polarisation effects into account.
Experimental transition probabilities arising from 4d8 5s2, 4d9 6s and 4d9 5d levels of Ag II and 3d8 4s2 level of Cu II were measured. A time-resolved system with a Nd-YAG laser that produced free neutral and ionized silver and copper plasma by ablation was used. Transition probabilities were deduced by measured branching ratio and experimental and theoretical data for radiative lifetimes. A comparison between our values and the theoretical ones is made where available.
Radiative lifetimes of n1P1 excited states (n = 9, 10) of netural mercury have been determined. Two techniques have been used -- time-resolved laser-induced fluorescence spectroscopy in a laser-produced mercury plasma and multichannel delayed coincidence method wth pulse electron excitation. Measured lifetimes are compared with previous results. The influence of the radiation trapping on the effective lifetimes has been investigated. The electron configuration interaction beween the 5d106s np1P1 and 5d96s2np1P1 (Beutler) series has been studied.
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