Shift and width measurements of the Stark-broadened ionized helium line at 1215 Å

Experimental Study of the Stark Broadened Helium Ion Lines Hell 121.5, 164.0 and 468.6 nm

“…The Balmer-/? profile measured by van Zandt et al [13] turned out to be wider than Kepple's theory, and the most recent investigations of Smith and Burgess [14] yield slightly enhanced wings of Balmer-a and Balmer-/?.…”

“…There is also weak agreement among the experi mental results for several Hell-lines [6][7][8][9][10][11][12][13][14], Recent investigations of the Paschen-1 line Hell 468.6 nm [6 -9] -which often has been used routinely to measure electron densities -yield profiles that lie between the profiles of Kepple [2] and of Greene [1], On the other hand, measurements by Jones et al [10] are in good accordance with Kepple's predic tions. Concerning the Balmer lines Hell 164.0 nm and Hell 121.5 nm.…”

“…the situation is even less satis factory. There are only few investigations [10][11][12][13][14], which show considerable deviations from each other. Older line profile measurements by Hessberg and Boetticher [11] as well as Eberhagen and Wunderlich [12] yield narrower profiles than the theory of Kepple for both lines.…”

“…Firstly, measured Balmer-a profiles were affected by optical depth in [11] and [14], requiring crucial corrections. Secondly, at least in [13] the Balmer-/? line core is influenced by hydrogen Lyman-a absorption due to 0340-4811 / 84 / 1 1 00-1041 S 01.30/0.…”

“…-Please order a reprint rather than making your own copy. [11] as well as van Zandt et al [13] have deduced the electron density from the line shape of the Hell 468.6 nm line. As pointed out above, there are still uncer tainties regarding this line, which influence the electron density measurements.…”