Effects of Time Ordering on Plasma-Broadened Hydrogen Profiles

Abstract

bound electrons equal in theory and experiment. The same practice is used for x-ray and y-ray Compton-profile normalization but not in the highenergy electron-impact method. For the other two theories the theoretical curves have been arbitrarily placed on the logarithmic scale in the best way to emphasize shape discrepancies 0The discrepancy between theory and experiment in the earlier (e, 2e) measurements 5 can be explained in part. Firstly, the theory used was slightly in error, since the sum over vibrational states was not carried out although these states were summed over in the experiment. Secondly^, there was a systematic error of 6% in the calibration of q.The small discrepancy between theory and experiment in the Compton-profile measurements gives rise to a more serious disagreement between the calculated and experimentally derived momentum distributions. This discrepancy could quite possibly be due to failure to satisfy binaryencounter conditions in the experiments. If this is indeed the case then, as in (e,2e), the measured Compton profiles will depend on the overlap of the initial target and final ion wave functions rather than the single-particle momentum densities. Of course at sufficiently high energy, closure over final states reduces the theory to dependence only on initial states.We would like to acknowledge very helpful conversations with Dr. R. A" Bonham, Dr c W. A.The plasma-(Stark-) broadened Balmer-line profiles of hydrogen measured during recent experiments 1 * 2 exhibit much less structure in their central regions than predicted by the most comprehensive theories. 3 " 7 This difference is quite serious since the plasma-broadened Balmer lines have found many applications as a convenient pre-The plasma-broadened R a and Hg spectral-line profiles of hydrogen were calculated retaining the time ordering in the S matrices of the width-shift operator by diagonalizing with the 0(4) group. Significant changes occur: The H a peak is decreased 15%, the halfwidth is increased 25%, and the H 0 relative dip is decreased 23% without significant alteration of the maximum intensity of half-width. Agreement with experiment is improved appreciably. 785

Hydrogen spectral lines with the inclusion of dense-plasma effects

“…In this way, the corre- The calculated H line profile for low electron densities agrees well with the unified theory results [32]. The disagreement with the shape of Ref.…”

“…2 resulted. An excellent agreement between the unified theory calculations [32] and our theory can be stated. At this point it is important to recall that the latter should be considered as a correct low-density result within the framework of the static-ion model [33,34].…”

Stark Broadening of the Hydrogen Balmer-α Line in Low and High Density Plasmas

“…2 of [33], were rather restricted in that the temperature was always close to 1 eV. (This figure also shows a comparison with an improved version [36] of the unified theory in which the electron broadening is calculated allowing for time-ordering.) This restriction and that to electron densities below 10 17 cm −3 was removed in Ref.…”

“…Based on a stabilized arc as light source, the experiments [33], results of which for H-α and D-α are summarized and compared with theory in Fig. (This figure also shows a comparison with an improved version [36] of the unified theory in which the electron broadening is calculated allowing for time-ordering.) (This figure also shows a comparison with an improved version [36] of the unified theory in which the electron broadening is calculated allowing for time-ordering.)…”

Experimental Study of Balmer-α Stark Broadening

“…Among various suggestions made in the recent literature [5,[10][11][12][13] (see discussion in Ref. [14,20]) to account for the disagreements between theory and experiment, the neglect of ion dynamics in current broadening theories appears to be the most convincing argument, since ion dynamic effects were observed experimentally in hydrogen line profiles by Kelleher and Wiese [14] and Wiese et al [15].…”