J. A. Aparicio

Stark widths of Xe II lines in a pulsed plasma

In this paper, we present a review of experimental work on Stark broadening of singly ionized xenon lines. Eighty lines, from close UV to the red region of the spectrum, have been studied. Stark halfwidths were compared with experimental data from the literature and modified semi-empirical calculations. A pulsed arc with 95% of helium and 5% xenon was used as a plasma source for this study. Measured electron densities Ne and temperatures T were in the ranges of 0.2–1.6 × 10 23 m −3 and 18 300–25 500 K, respectively.

Stark broadening and shift measurements of visible Si II lines

A set of experimental Stark width and shift parameters of visible singly ionized silicon spectral lines is reported in this paper. Measurements have been made on a pulsed plasma generated in a linear discharge lamp filled with a mixture of silane and helium. Electron density and temperature in this plasma range from 0.2 to 0.9 × 1023 m−3 and from 16 000 to 20 000 K respectively. Electron density has been simultaneously determined by two-wavelength interferometry and from Stark broadening of He I 501.6 nm, He I 728.1 nm and Hα lines. Temperature has been simultaneously determined from a Boltzmann plot of He I lines, from absolute emission of He I lines and from a Boltzmann plot of Si II lines. Dependences of measured Stark parameters on electron density and temperature have been investigated and the final results have been compared with most of the previous experimental data as well as with some theoretical models.

Stark broadening measurements of Xe III spectral lines

This work reports measured Stark widths of doubly ionized xenon lines. Pulsed arc was used as a plasma source. Measured electron densities and temperatures were in the ranges of (0.2 – 1.6) × 10 23 m −3 and 18 300–25 500 K, respectively. Stark halfwidths of lines from 6s–6p, 6s–4f and 5d–6p transitions have been measured and compared with available experimental and theoretical data.

Experimental measurements of shifts and asymmetries of He II Pα and Pβ spectral lines

Red shifts and asymmetries of He II Pα 468.5682 nm and Pβ 320.3104 nm lines were measured in a pulsed plasma at an electron density measured by two-wavelength interferometry which ranges from 5.54 × 1022 m−3 to 7.48 × 1022 m−3 with uncertainty of 10%. Temperature ranges from 1.70 to 1.83 eV, and has been determined from intensities ratio of Pα and Pβ lines. Shifts for these lines were obtained using as reference lines Cd I 467.8149 nm and He I 318.7745 nm respectively. Measurements of asymmetries have been represented using reduced wavelength units. All results have been compared with previous experimental and theoretical data.

Stark broadening measurements of low-intensity singly and doubly ionized xenon spectral lines

Aims. The aim of this work is to provide Stark parameters of low intensity Xe II and Xe III spectral lines from which scarce or null previous information exist.This work completes the measurements of ionized Xenon parameters developed in the last few years and extends Stark parameters database for astrophysical applications. Methods. All Stark parameters were measured in a pulsed arc plasma with 95% of helium and 5% of xenon. Measured electron densities and temperatures were in the range of (0.2−1.7) × 10 23 m −3 and 18 000−25 500 K, respectively. Results. As a whole 25 Stark widths and 29 shifts of Xe II spectral lines have been measured, along with 10 Stark widths and 6 shifts of Xe III. Some of the presented data are compared to theoretical values calculated using modified semiempirical formulae, as well as to other available experimental results.

Ne II Stark Width and Shift Regularities

Stark widths of 48 and Stark shifts of 36 Ne II spectral lines have been measured in a low-pressure pulsed arc plasma. Of these, 21 widths and 25 shifts have not been previously reported. This has allowed us to analyze Stark width and shift regularities in some multiplets and transition arrays of this species. The electron density and temperature in this experiment were in the range 1.12-1.97 × 1023 m−3 and 25,000-45,000 K, respectively. The results have been compared to data from previous experimental work, as well as to theoretical models. Stark parameter regularities experimentally determined in this work provide a basis for estimating the Stark parameters for Ne II lines that have not yet been observed.

Stark parameters of neutral helium 318.8 nm line

Aims. Our aims is to measure with good accuracy the Stark parameters (width and shift) of the He I 318.8 nm (2s 3 S-4p 3 P°) line and to calibrate Stark width and shift dependencies of this line as a function of the electron density. In this way, it is possible to obtain an alternative method of diagnosing the plasmas of astrophysical origin and to check the quality of theoretical models that predict these parameters. Methods. We made a spectroscopic and interferometric analysis of a pulsed plasma. The electron temperature was obtained with an intensity ratio of He II lines and ranges from 19000 to 23000 K. Electron density was determined by interferometry ranging from 1.25 × 10 22 m -3 to 6.22 × 10 22 m -3 . Results. These experimental results are new for these plasma conditions. When joined with previous bibliographic data, they allowed us to obtain an empirical calibration expression for the Stark width and the shift of this line in a broad range of electron densities. Comparisons with different theoretical models are also included.

Measurement of Stark broadening and shift constants of singly ionized krypton lines

Stark widths and shifts of 25 visible singly ionized krypton lines are presented in this paper. All of them were measured in a pulsed discharge lamp from a mixture of krypton and helium. The electron density, which typically ranges from 0.2 to 1.8×1023 m-3 has been simultaneously determined from two-wavelength interferometry and from the Stark broadening of the He I 388.865 nm. The excitation temperature, from 16 000 to 24 500 K, has been measured from the Boltzmann plot of Kr II lines, which has allowed us to recalculate some Kr II transition probabilities. Comparisons with most of the data published to date about this topic in Kr II are also included.

Irregularities of Stark parameters of Xe II spectral lines

This work reports measurements of nine Stark widths and nine Stark shifts of Xe II spectral lines. These line parameters have been measured in a pulsed arc plasma in electron density and temperature range (0.2–1.6) × 1023 m−3 and (18 000–25 000) K, respectively. The results are compared to other experimental data as well as with theoretical values calculated from modified semiempirical formulae. Stark parameters of the lines belonging to the same multiplet are usually very close. The results obtained in this work show that in some cases very clear intramultiplet irregularities exist. These measurements, as well as some results from the previous works of this group, have been used to analyse the origin of these irregularities.

Stark shift measurements of Xe II and Xe III spectral lines

Stark shift measurements of singly and doubly ionized Xe spectral lines are presented in this paper. Shifts of 110 Xe II lines and 42 Xe III lines are reported, including a significant number of new results. A low-pressure-pulsed arc with 95% of He and 5% of Xe was used as a plasma source. All measurements were performed under the following plasma conditions: electron density (0.2–1.4) × 10 23 m −3 and electron temperature 18 000–23 000 K. The measured Stark shifts are compared with other experimental and theoretical data.