M. Platisa

Mg II spectral line broadening in helium, oxygen and argon-helium plasmas

Stark widths (W) and shifts (d) of the astrophysically very important six (279.0777, 279.5528, 279.7998, 280.2705, 292.8633 and 293.6510 nm) singly ionized magnesium (Mg II) spectral lines in helium, oxygen and argon-helium plasmas have been measured at electron temperatures between 30 000 and 52 300 K and electron densities between 1.2 × 10 23 and 1.65 × 10 23 m −3 . They are the first experimental results obtained at electron temperatures higher than 20 000 K. A linear, low-pressure, pulsed arc has been used as an optically thin plasma source. The magnesium atoms, as impurities in the driving gases, have been introduced by erosion from the pure magnesium bands fixed on the discharge electrodes. Our measured Stark width and shift values have been compared to the existing experimental and theoretical data. We have found a good agreement with W and d values calculated by the semiclassical perturbation formalism (SCPF).

Stark broadening and shift of singly and doubly ionized fluorine spectral lines

Stark widths and shifts of eight singly and one doubly ionized florine spectral lines have been measured in a pulsed linear are plasma in SF6 at two different electron densities and temperatures, and compared with existing theoretical results. Our data and those of other authors were used to investigate some regularities of Stark broadening within homologous group of halogene elements.

ON THE STARK WIDTH REGULARITIES IN THE SINGLY IONIZED SPECTRA

The existence of the Stark width dependence on the upper-level ionization potential of the quantum transition have been presented for the sixteen types of transitions in spectras of nine singly ionized atoms: C II, N II, O II, F II, Ne II, P II, S II, Cl II and Ar II. On the basis of established regularities the Stark width values of 43 spectral lines, not measured or calculated before, have been predicted. Critical analysis of the existing experimental Stark width data is also given.

Stark broadening of S(III) and S(IV) lines

Abstract Measurements of the Stark widths of doubly and triply ionized sulfur lines were made in a low pressure, pulsed arc plasma of electron density 5.1 × 1016 cm-3 at an electron temperature of 28, 500°K. The experimental S(III) and S(IV) Stark-profile halfwidths were compared with calculated values obtained with Griems semiempirical and approximate semiclassical approach. The experimental results agree better with the semiclassical results.

Stark broadening of Si III and Si IV lines

The halfwidths of seven Si III and four Si IV lines have been measured in a pulsed arc. The electron density of 5.8*1016 cm-3 was determined by laser interferometry, while the electron temperature of 25600 K was measured from a Boltzmann plot of the relative intensities of the Cl III lines. The experimental Si III and Si IV Stark-profile halfwidths were compared with calculated values obtained from Barangers semiclassical (1962) and Griems semiempirical (1968) approaches. The agreement between experiment and semiempirical (1968) approaches. The agreement between experiment and semiempirical results is within 15%.

ON THE S III AND S IV SPECTRAL LINES STARK BROADENING PARAMETERS

Stark widths of three S III spectral lines belonging to 4p–5p transitions have been measured and calculated. Measurements have been performed in a low pressure linear pulsed arc at 2.1 × 1023 m−3 electron density and 40 000 K electron temperature. Calculations for S III lines were performed by using the modified semiempirical approach. For S IV 4s 2S–4p 2Po multiplet, calculations were performed within the semiclassical perturbation formalism. The obtained results were compared with other theoretical and experimental data.

Measured Stark widths of doubly and triply ionized silicon spectral lines

The Stark widths of ten Si III and seven Si IV spectral lines have been measured for the electron density range of 1.4*1023 m-3-3.0*1023 m-3 and for an electron temperature range of 29000-64000 K in a pulsed linear arc plasma discharge in O2 and SF6. Experimental values of Stark widths for ionized silicon spectral lines follow a simple dependence on the upper level ionization potential of the transition.

Experimental stark widths of C(II)u.v. lines

Abstract Measurements of the Stark widths of two singly ionized carbon lines were made in a low pressure pulsed arc plasma of electron density 4.9 × 1016 cm-3 at a temperature of 26,300 K. The measured half-widths agree within about 16% with calculated widths.

Electron impact broadening of ionized chlorine lines

A pulsed arc in dichlorodifluoromethane was the source of a plasma used to measure, on a shot-to-shot basis, profiles of 33 lines of singly ionized chlorine. An electron density of 6.80 and 5.03*1016 cm-3 was determined by the laser interferometry at a single wavelength, while electron temperatures 18600 K and 14500 K were measured from relative intensities of Cl II lines. The experimental Cl II Stark profile half-halfwidths were compared with theoretically calculated values. A systematic and increasing discrepancy between experimental and theoretical values, computed from Griems semiempirical formula, for the lines of Cl II multiplets with the energy levels approaching the ionization threshold was found.

Measured stark widths of BI, BII, BIII and Nal spectral lines

Stark widths of six spectral lines from neutral and multiple ionized boron and three spectral lines from neutral sodium spectra have been measured in a pulsed linear arc plasma. All the measurements have been done in the electron density range of 1.66 × 1023–2.55 × 2023m-3 and in the electron temperature range of 40 000-50 000 K. Some of these experimental values are compared with existing theoretical data.