Knowledge Bank

The flame spectrum of Ba(g) burning at low pressure in the oxidants $N2O$, $NO2$ and $O2$ is observed to include a long progression and an overlapping short progression bands in the violet and ultraviolet. A vibrational analysis is possible with the aid of theoretical calculations by $Michels1$ and the analysis of perturbations in the $A1\Sigma +-X1\Sigma +$ system by $Field.2$ The bands are assigned to $A^\{\backslash prime\}^\{1\}\backslash Pi\; -\; X^\{1\}\backslash Sigma^\{+\}$. The long progression is ($v\prime$, 0) with $v\prime$ running from 13 to 29. The short progression is ($v\prime$, 1) with $v\prime$ running from 22 to 28. For the parameters of the $A^\{\backslash prime\}^\{1\}\backslash Pi$ state we obtain $\nu ~oo$ = 17569 $\pm$ 15 $cm-1$, $\omega o=442.8$ $\pm$ $1.1cm-1$, and $\omega oxo=1.71$ $\pm$ .01 $cm-1$. The first two are in remarkably good agreement with $Field.2$