Vibrational population distributions of ground state barium oxide formed in the Ba+O2 and Ba+N2O reactions

The relative ground state vibrational population distributions of BaO formed in the chemical reactions Ba+O2 and Ba+N2O have been measured as a function of total pressure between 0.3 and 10 torr using the technique of dye laser induced photoluminescence. Interpretation of these results together with previously reported excited state vibrational distribution measurements by Jones and Broida for the Ba+N2O reaction suggest that a population inversion does exist between A 1Σ+(v′=1) and X 1Σ+(v″=7)BaO at ?16 torr.