A new, definitive analysis of a very old spectrum: the highly perturbed A2Πu-X2Πg band system of the chlorine cation (Cl2+).

The laser-induced fluorescence spectrum of jet-cooled chlorine cation has been recorded in the 500-312 nm region with high sensitivity and rigorous vibrational and spin-orbit cooling. More than 80 bands of the highly vibrationally perturbed A (2)Π(u)-X (2)Π(g) electronic transition have been detected and shown to originate from the Ω = 3/2 spin-orbit component of v = 0 of the ground state. The spectrum extends some 3700 cm(-1) to the red of any previously published report and the 0-0 band has been identified for the first time.

The ns and nd Rydberg states of O2 described by Hund's case (e).

Using Hund's case (e) representation, we have obtained a simulation of the 5s Rydberg states of O(2) for J=2 by fitting the experimental data obtained recently by Sheard et al. [J. Chem.

Assignment in the near-threshold absorption spectrum of N2.

The absorption spectrum of N(2), just above the first ionization limit, in the region between 125,750 and 126,600 cm(-1), is dominated by two broad features which have the appearance of the towers of a "cathedral." Recently, this energy region has been measured by Sommavilla et al. [J.