M. Ortiz

Measured Stark widths of several Ni II spectral lines

The Stark broadening parameters of 17 lines of Ni II have been measured in a plasma produced by ablation of an Al–Ni alloy with a Nd:YAG laser. The broadening parameters were obtained with the target placed in molecular argon at 6 Torr, which provides appropriate measurement conditions. A Boltzmann plot was used to obtain the plasma temperature (16u2009500 ± 2100 K) and published values of the Stark broadening in Al II to obtain the electron density ((1.07 ± 0.10)1017cm−3); with these values, the plasma composition was determined by means of the Saha equation. The local thermodynamic equilibrium condition was checked. Contributions to broadening arising from a mechanism different from the Stark broadening as well as self-absorption influence were estimated for every studied line. A comparison was made with previous experimental values and recent theoretical estimates of the Stark broadening where possible.

Measurement of the Stark broadening for several lines of singly ionized gold

The Stark broadening parameters of 26 lines of Au II have been measured in a plasma produced by ablation of a gold target with a Nd:YAG laser. In order to obtain suitable experimental conditions for the homogeneity and stability of the plasma, a study of the temporal plasma evolution in helium, argon and nitrogen at different pressures was made. The broadening parameters were obtained with the gold target placed in molecular argon at 6.5 Torr, which provides appropriate measurement conditions. A Boltzmann plot was used to obtain the plasma temperature [16 200 ± 1400 K] and by means of the Saha equation the electron density [(1.45 ± 0.23) × 1017 cm−3] and the plasma composition were determined. The local thermodynamic equilibrium condition was checked. Contributions to broadening arising from a mechanism different from the Stark broadening as well as self-absorption influence were estimated for every studied line.

Radiative parameters for some transitions arising from the 3d94d and 3d84s2 electronic configurations in Cu II spectrum

Transition probabilities of 41 transitions originating from the 3d94d and 3d84s2 electronic configurations of singly ionized copper have been determined using laser-induced breakdown spectroscopy. The Cu II ions have been produced by laser ablation. The experimental relative transition probabilities have been converted into an absolute scale using measured branching fractions and theoretical radiative lifetimes of the corresponding upper states obtained by a relativistic Hartree–Fock method taking core-polarization and configuration interaction effects into account. Comparison of the new results with previously available data is also presented.

Experimental transition probabilities for spectral lines of Re II

Experimental transition probabilities for 37 spectral lines of Re II (15 measured for the first time) have been obtained from a plasma produced by ablation of a Zn?Re alloy with a Nd:YAG laser. The plasma evolved in air at atmospheric pressure, and measurements were performed for the following plasma parameters: an electron density of (1.27 ? 0.19) ? 1017 cm?3 and an electron temperature of 11?200 ? 400 K. The relative intensities were placed on an absolute scale by the combining branching fractions with the measured lifetimes and by comparing well-known lines using the plasma temperature. Some plasma parameters, such as the temperature and the electron density, were also obtained to provide a local thermodynamic equilibrium environment and an optically thin plasma. Comparisons were made to previously obtained experimental and theoretical values wherever possible.

Experimental stark widths of six UV lines of ZnII

The Stark broadening parameters of six lines of ZnII (four measured for the first time) have been experimentally determined in a plasma produced by ablation of a Cd?Zn alloy with a Nd:YAG laser and a Zn content under 10%. The broadening parameters were obtained with the target placed in molecular argon at 6 Torr, which provides appropriate measurement conditions. A Boltzmann plot was used to obtain the plasma temperature (30?400 ? 6400 K) and published values of the Stark broadening in CdII to obtain the electron density ((5.38 ? 0.54)1016 cm?3); with these values the plasma composition was determined by means of the Saha equation. The local thermodynamic equilibrium condition was checked. Contributions to broadening arising from a mechanism different from the Stark broadening as well as self-absorption influence were estimated for every studied line. A comparison is made with previous experimental values and recent theoretical estimates of the Stark broadening where possible.

Possibility of LIBS for transition probabilities determination

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.

Measured oscillator strengths in singly ionized molybdenum

In this article, 112 oscillator strengths from Mo II have been measured, 79 of which for the first time. The radiative parameters have been obtained by laser-induced breakdown spectroscopy (LIBS). The plasma is produced from a fused glass sample prepared from molybdenum oxide with a Mo atomic concentration of 0.1%. The plasma evolved in air at atmospheric pressure, and measurements were carried out with the following plasma parameters: an electron density of cm−3 and an electron temperature of K. In these conditions, a local thermodynamic equilibrium environment and an optically thin plasma were confirmed for the measurements. The relative intensities were placed on an absolute scale by combining branching fractions with the measured lifetimes and by comparing well-known lines using the plasma temperature. Comparisons were made to previously obtained experimental and theoretical values wherever possible.

Experimental oscillator strengths in ReI

The oscillator strengths of 30 lines of ReI (26 of them have been measured for the first time) have been measured in a plasma produced by ablation of a Zn–Re alloy with a Nd:YAG laser. The radiative parameters were obtained with the target placed in molecular argon at 8 Torr, which provides appropriate measurement conditions. Branching fractions combined with measured lifetimes and a Boltzmann plot were used to set the relative intensities in an absolute scale. Some plasma parameters, such as the temperature and the electronic density, were obtained in order to provide a local thermodynamic equilibrium environment and an optically thin plasma. A comparison is made with previous experimental and theoretical values wherever possible.

Transition probabilities for lines from 4d96s, 4d95d of Ag II spectrum and from 3d94d of Cu II lines

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.

Determination of isotope shifts in 2,4-, 3,4- and 2,6-dichlorotoluene isomers in a supersonic beam

Abstract By using resonance-enhanced two-photon ionization in a supersonic beam, photoionization spectra of the m/z 160, 162 and 164 species of the 2,4-, 3,4- and 2,6-dichlorotoluene isomers at 0.8 K rotational temperature have been obtained in the 2800 A spectral region. The ions have been analyzed according to their masses in a time-of-flight mass spectrometer. Isotope shifts of the order of tenths of cm −1 have been determined for the first time for the studied molecules. The spectra obtained have been interpreted by considering the geometrical structure and symmetry of every isotopomer, and values for the rotational constants in the upper and lower states of the electronic transition have been obtained in agreement with the experimental results.