Stark effect at high electric fields and Stark ion broadening widths and shifts for different microfield distributions at quasistatic approximation in atomic oxygen spectra.

Abstract

Studies of the static Stark effect are reported for the multiplets at 615.8, 645.6, 777.6, 822.4, 844.9, and 926.5 nm (vacuum wavelengths) of atomic oxygen, which are important for various applications. From the Stark patterns recorded at very high electric fields up to 780 kV/cm, we have determined the differences of the scalar polarizabilities Δα_{0} and the tensor polarizabilities α_{2} for the investigated lines. For most of the lines we present the first-obtained experimental results. The Stark broadening of the studied lines by non-neutral plasmas in the ion density range of 10^{13}-10^{19}cm^{-3} was analyzed based on these results. The quasistatic approximation and three distinct microfield distributions were employed, which corresponded to different types of coupling in the plasma, namely the Holtzmark, Mayer, and irregular cluster distributions. Ion broadened widths and shifts were obtained from the simulated line shapes for different microfield distributions and ion densities. The analysis of these outcomes enabled us to determine their correlations with the independently determined Δα_{0} and microfield distribution, ultimately enabling us to ascertain the contour of the microfield distribution itself.