PLASMA BROADENING AND SHIFTING OF SPECTRAL-LINES ALONG THE ISOELECTRONIC SEQUENCE OF BORON

Temperature dependence of the Stark widths (N III and F V) and shifts (N III and O IV) of the 3s(2)S-3p(S-1)P-2(0) and 3p(2)P(0)-3d(S-1)D-2 transitions have been studied theoretically using the impact semiclass ical method and experimentally observed in the plasma of a low pressur e pulsed are. Plasma electron densities were determined from the width of the He II P-alpha line while electron temperatures were measured f rom the relative line intensities. To estimate the influence of differ ent ions on the width and shift of lines, evaluations of the plasma co mposition data were performed and, in conjunction with our theoretical results, the contribution of ion broadening was estimated. Within the estimated uncertainties experimental Stark widths agree well with the results of our semiclassical electron impact widths in the studied el ectron temperature range. For the conditions of the present experiment , estimated contribution of the ion broadening has never exceeded five percent of the total width. So within the precision of this experimen t it was not possible to detect its presence with certainty. Along the boron isoelectronic sequence the experimental widths and shifts agree with semiclassical electron impact data predictions. In the case of O Iv lines the inclusion of the energy levels with different parent ter ms in our semiclassical calculations of the Stark widths and shifts im proved the agreement between theory and experiment considerably. Compa risons of the experimental widths with simple theoretical formulas for estimation of plasma broadened linewidths show an agreement within es timated uncertainties.