Matrix-isolation study of the co2 lowest triplet state

We have investigated the emission of a CO2 molecule isolated in an Ar matrix at 4.7 K in the spectral region between 350 and 550 nm. This emission is a continuum with a lifetime of 570 ms. We assign it to the transition from the lowest triplet state (bent) 3B2 to the fundamental state (linear) 1Σ+g.