Wavelengths, energy levels, and analysis of the second spectrum of chlorine (Cl ii)*

Abstract

We have observed the spectrum of singly ionized chlorine (CI ii) with grating spectrographs from 500 to 11 000 A using a ring discharge and a pulsed rf-discharge source. The accuracy of the observed wavelengths is about 0.002 A from 500 to 3000 A and 0.01 A from 3000 to 11 000 A. The number of known energy levels has increased from 140 to 270 and the number of classified lines from 600 to over 1100. We have found 25 levels of 3p3ng (n = 5–8) and 59 levels of 3p3nf(n = 4–10), including all 20 levels of 3p3 (2D)4f. Combinations with the latter levels gave new information on the singlets in the 3p3 3d configuration, which led to the rejection of some levels, the establishment of others, and many changed assignments. Ab initio energy-level and spectrum calculations and least-squares energy-level fits showed large interactions between the 3s 3p5, 3s2 3p3 3d, and 3s2 3p3 4d configurations. The ionization limit of Cl+ is 192070 ± 1 cm−1.