ROTATIONAL ANALYSIS OF THE THRESHOLD PHOTOELECTRON-SPECTRA OF ROOM-TEMPERATURE AND JET-COOLED CO2

The rotational structure associated with (X) over tilde (2) Pi(g) (000 ) ground ionic state of CO2+ has been investigated by threshold photoe lectron spectroscopy and semiempirical calculations based on the distr ibution of Rydberg state levels at n = 2000. The calculations are in v ery good agreement with the rotationally resolved spectra for the (X) over tilde (2) Pi(g,3/2) and (X) over tilde (2) Pi(g,1/2) spin-orbit l evels for both room temperature and supersonically cooled ground state CO2. Intensity anomalies are partly explained by decay mechanisms inv olving rotational and spin-orbit autoionization. (C) 1994 American Ins titute of Physics.