Knowledge Bank

The vibrational population distributions of ground state BaO formed by the reactions $Ba+O2$ and $Ba+N2O$ at 0.3 to 10 Torr have been measured. A scanning rhodamine 6G cw dye laser is used to pump $X1\Sigma (\nu \prime \prime )\to A1\Sigma (\nu \prime )$ transitions from sequential ground state vibrationa1 levels $(\nu i\prime \prime )$, while a 3 nm resolution monochromator detects only the photo-luminescence originating from this $A1\Sigma (\nu \prime )$ in a band outside the dye laser region. Shown below are the relative populations, determined from laser induced fluorescence intensities, of the $\nu \prime =0$ through $\nu \prime =7$ vibrational levels of $BaOX1\Sigma$ formed in the $Ba+02$ reaction at 0.3 Torr. [FIGURE] Similar data for the $Ba+N2O$ reaction suggest that a population inversion may exist between $BaO A1\Sigma (\nu \prime =1)1$ and $X1\Sigma (\nu \prime \prime =7)$ at 16 Torr.