Experimental stark widths and shifts in the 3p ³D - 3d ³F° O III transition

Abstract

Stark widths (W) and shifts (d) of 3 doubly ionized oxygen (O III) spectral lines (326.085 nm, 326.532 nm and 326.720 nm) in the 3p 3D-3d 3P transition have been measured in the optically thin helium-oxygen plasma created in a linear, low-pressure, pulsed arc discharge at a 26 000 K electron temperature and 1.1·1023 m-3 electron density. Our Stark shifts are the first measured data at an electron temperature smaller than 30 000 K. No theoretical W and d data exist in this O III transition. Our W and d values are compared with the existing experimental data. On the basis of the found agreement among the experimental W and d values at a 26000 K electron temperature we have evaluated their dependence on the electron temperature ranged between 10000 K and 50000 K.