Knowledge Bank

Further analysis of the visible region electronic band systems of YOH and YOD has been performed. Three electronic states, $X~1\Sigma +,B~1\Pi$ and $C~1\Sigma +$, have been found. Wavelength-resolved fluorescence spectra have given a large amount of information about the vibrational frequencies of the $X~1\Sigma +$ state. Exciting from the $v2\prime \prime =1$ level of the ground state, we have been able to determine the separation of the $l=2$ or 0 levels. The geometric structure of the ground state is found to be $r(Y-O)=1.94840(58)${\AA} and $r(O-H)=0.9215(53)${\AA}. Due to the perturbed nature of the $B~1\Pi$, and $C~1\Sigma +$ states, an accurate determination of their geometries has not been possible. We have tentatively identified several members of the $\nu 3$ progressions in these states.