High-resolution electron spectroscopy of the 1s23lnl' Be-like series in oxygen and neon. Test of theoretical data: II. Experimental results

A complete and accurate experimental test of theoretical spectroscopic data sets (state positions, lifetimes) available for the n = 3–5 terms of the 1s23lnl' Rydberg series of oxygen and neon ions is presented in a series of two papers. This result was achieved by fitting our high-resolution electron spectra with post-collisional lineshapes calculated with the help of these spectroscopic data. In this second paper we apply the fitting procedure described in the preceding companion paper (I) to the analysis of high-resolution electron spectra measured in O6+ (1s2) + He, H2 and Ne8+ (1s2) + He collisional systems at 10 qkeV collision energy (q is the ion charge). Singlet states alone are found to be excited in oxygen; they also explain most of the neon lines; in the latter case a possible contribution of triplet states is discussed. Many 1s23lnl' 1L transitions are identified for the first time. A quantitative comparison between measured and calculated positions clearly points to the best theoretical data currently available. Finally, a first identification of some 4l4l' 1L transitions observed in the neon spectrum is also proposed. From this huge spectroscopic work, we extract the first experimental partial branching ratios for autoionization into the 1s22l ionization continua for a large number of 1s23lnl' 1L states, which are compared with the total ones calculated by other authors; we deduce that populations of |ML | = 0 and 1 magnetic sublevels are nearly identical. The double-capture process is also briefly characterized by comparing relative populations of many n = 3–5 states; it is found that the same states are populated in O6+ + H2 and Ne8+ + He collisional systems with the same relative populations.