J. Purić

Stark broadening and regularities of ionized neon and argon spectral lines

Stark widths of five Ne III, five Ne IV, one Ar III and nine ArIV spectral lines have been measured in a linear-pinch discharge plasma. The results were compared with existing experimental and theoretical results, and used to establish several types of regularities. Electron densities determined with single-wavelength laser interferometry were 2.18·1023 m−3 and 2.80·1023 m−3 in neon and argon plasma, respectively. The electron temperatures determined from the Boltzmann slope of several Ne III spectral lines, and ratios of Ne III to Ne IV or Ar III to Ar IV spectral lines were 59 000 K and 42 000 K in neon and argon plasma, respectively. The investigated spectral lines originate predominantly, from 3s–3p and 3s′–3p′ Ne III and Ne IV, and from 4s–4p and 4s′–4p′ Ar III and Ar IV transition arrays. The emphasis is on the Stark width (θ) dependence on the upper level ionization potential (I), the emitter core net charge (z) and electron temperature (T) for a given electron density. This dependence was found to be of the form: θ=az2T−1/2I−b, wherea andb are constants within(i) several stages of ionization of neon or argon and(ii) within nitrogen like (NI, O II, F III and Ne IV) 3s–3p or phosphorus like (P I, S II, Cl III and Ar IV) 4s–4p transition arrays. The established overall trends were used to predict the Stark widths of univestigated spectral lines originating from the given transition arrays.

Stark broadening and shift of neutral and singly-ionized mercury lines

Abstract Stark widths and shifts of four Hg I and two Hg II spectral lines have been measured in a linear, low-pressure, pulsed arc operated in a nitrogen-mercury vapor mixture. All of the experimental data were recorded at electron densities up to 4.2 x 1022m-3 and an electron temperature of 37,000 K. The experimental Hg I and Hg II Stark widths and shifts are compared with values calculated on the basis of semiclassical and semiempirical formulae.

Stark widths dependence on the upper level ionization potential and the rest core charge of the emitter within 3s–3p and 3p–3d transition arrays

Abstract Stark width simultaneous dependence on the upper level ionization potential and rest core charge of the emitter has been evaluated and discussed. It has been verified that the found relations, connecting Stark broadening parameters with upper level ionization potential and rest core charge of the emitters for particular electron temperature and density, can be used for prediction of Stark line width and shift data in case of ions for which observed data, or more detailed calculations, are not yet available.

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.

Stark broadening and shift of singly-ionized argon spectral lines in higher multiplets

Abstract Stark-widths and -shifts of 25 singly-ionized spectral lines, mostly higher multiplets, have been measured and compared with existing experimental and theoretical results. A linear pinch discharge was used as a plasma source. Electron densities determined with single wavelength laser interferometry and using the visible transition of an He-Ne laser were (0.86-2.12) × 1023 m-3. An electron temperature of 26,000 K was derived from the Boltzmann slope of several Ar II spectral lines and from intensity ratios of Ar III spectral lines to several Ar II spectral lines. Our data and those of other authors were used to investigate the nature of the Stark-broadening dependence on the following: (i) upper-level ionization potential of the spectral line belonging to the 4p-4d transition array and (ii) electron temperature. The established trend is used to predict Stark-widths of as yet uninvestigated spectral lines originating from the given transition array.

Stark broadening and shift of multiply ionized carbon spectral lines

Stark widths and shifts of sixCII, threeCIII and twoCIV spectral lines have been measured in a linear pinch discharge plasma and compared with available experimental and theoretical data. Electron density, (0.86−1.64)×1023 m−3, was determined by single wavelength laser interferometry using the visible 632.8 nm transition of He-Ne laser. The electron temperature of 38000 K was derived from the Boltzmann slope of severalCII spectral lines, and ratios of severalCII toCIII spectral lines. The stark widths (w) dependence on:(i) the upper-level ionization potential (I) of corresponding lines;(ii) net charge (z) of the emitter core seen by the optical electron undergoing transition, and(iii) electron temperature (T) was found to be of the form:w=az2T−1/2I−b. However, it should be noticed that the essential role in the obtained trends belongs to the energy of the emitter core. The established overall trend is used to predict Stark widths of uninvestigated spectral lines originating from the given transition arrays.

Stark-broadening regularities of lithium-like and sodium-like isoelectronic sequences

The Stark width (w) of spectral lines of multiply ionized atoms as a function of the upper-level ionization potential (I), the net core charge (z) and the electron temperature (T), was found to be of the form: w=az2T−1/2I−b normalized to 1×1023 m−3 electron density for a given transition array. Coefficientsa andb are independent of the upper-level ionization potential, the net core charge, the electron temperature and density. This paper proves the validity of this equation for Stark widths in domains of electron densities of (0.5–1.5)×1023 m−3 and temperatures of 20 000–80 000 K. The reduced Stark width (wT1/2/z2) dependence on the inverse value of upper-level ionization potential is represented by a linear trend (in log-log scale) of the experimental and relevant theoretical results within maximal scatter of less than ±30%. For a givenns-np transition array, this trend is equally applicable to spectral lines of (i) successive ionization stages of the same atom and (ii) ions of isoelectronic sequences of the second and third periods of the periodic system. It is also shown that coefficientsa andb depend on the energy state of the electron emitter core. Using the obtained trends, one can quite successfully predict the Stark width of spectral lines of corresponding transitions that have not yet been measured.

Stark shifts of Cl I and Cl II lines

Abstract Stark shifts of three neutral lines and thirty two singly ionized chlorine lines have been measured in pulsed arc plasma and compared with theory. The agreement is good for Cl I (7744, 9 A) but less satisfactory for Cl II lines.

Stark broadening of singly and doubly ionized iodine spectral lines

Abstract Stark broadening parameters of three singly ionized and three doubly ionized spectral lines have been measured in a pulsed linear arc plasma at 1.1×10 23 m -3 electron density and 64000 K electron temperature.