Observations on Collisional Stark Broadening in Radio Frequency Discharges

The profiles of low Balmer lines emitted from a radio frequency discharge (N 1023 cm-3) are expected to be in the domain of collisional electron Stark broadening, except for the far parts of the line wings. In order to accomplish a more accurate comparison with the modified generalized impact theory and with the quasi-static theory (including shielding and correlation effects) for the ions , or the ions and electrons, the contributions other than Stark contributions of the observed H -profile are quantitatively evaluated. Thus for the main body of the profile, the electron broadening contribution is found small compared to that of the ions; the half-width is almost accounted for by the ion broadening contribution. However, toward the far parts of the line wing, where a transition to quasi-static electron broadening can be expected, a slow buildup of a considerable electron broadening contribution is observed, finally equaling the ion contribution.