Stark-broadening regularities of prominent multiply-ionized-oxygen spectral lines in plasma

Stark widths of two O i i, twenty-four O i i i, four O i v, and two O v spectral lines have been measured and compared with the experimental and theoretical data available. A linear pinch discharge was used as the plasma source. The electron density in the range (1.30–2.20)×${10}^{23}$ ${\mathrm{m}}^{\mathrm{-}3}$ was measured by single-wavelength laser interferometry using the visible λ=632.8 nm transition of a He-Ne laser. The electron temperature of 42 500 K±10% was determined from the Boltzmann slope of several O i i i spectral lines and from some O i i-to-O i i i spectral line intensity ratios. For O i i i spectral lines originating from the same type of transition, the Stark-width (w) dependence on the upper-level ionization potential (I) was found to be of the form w=${\mathrm{AI}}^{\mathrm{-}B}$, where A and B are constants independent of the ionization potential I. Stark-width dependences on the emitter-core net charge (z) and simultaneously on the upper-level ionization potential (I) were evaluated within the framework of a semiempirical approach and found to be of the form w=A’ $z^2$ $I^{\mathrm{-}n}$. The established overall trends were used to predict Stark widths of uninvestigated spectral lines originating from the given 3s-3p and 3p-3d transition arrays, with an accuracy better than ±30%.