ABSTRACT
This chapter develops formulas that predict the line positions and the intensity distribution throughout the region of intermediate coupling near the thresholds, in terms of a few experimentally accessible parameters. The development relies on Seaton’s multichannel quantum defect method (QDM) which has thus far received only limited application. Extension of accurate spectral analysis to the proximity of the ionization threshold requires now an “exact” treatment of the rotational energy; this task is quite manageable under the circumstances considered in the chapter. The treatment of the spectral region between the two ionization thresholds involves many ramifications. The alternations of intensity in this part of the spectrum will be described in a manner slightly different from that of Beutler.
