Selective detection of O(1S) and CO (a3Π) following electron impact on CO using solid xenon Original Research Article

The neutral metastable species O(1S) and CO(a3Π) produce distinctly different red and UV emissions respectively within a few microseconds of their impact on a surface of solid Xe. This effect has been employed as a novel means of detection in a crossed beam experiment to obtain time-of-flight (TOF) spectra and relative cross sections of both species following electron impact on carbon monoxide. TOF spectra of O(1S) show five possible dissociation channels. Semi-quantitative partial potential curves were constructed for the parent molecular states of two of those channels. The relative cross section for O(1S) production was made absolute by comparison with production of the same from O2. The cross section reaches a maximum of 5×10−19 cm2 at 100 eV. The relative cross section for CO(a3Π) production includes cascade from the higher triplet states of CO and is uncontaminated by the 10 e V metastable state of CO.