ROTATIONAL ANALYSIS OF BANDS OF THE $\tilde{A}^{2}A_{2} - \tilde{X}^{2}B_{1}$ ELECTRONIC TRANSITION OF $ClO_{2}$

$^{1}$J.B. Coon, F.A. Cesani and C.M. Loyd, Discuss. Faraday Soc. 35, 115, (1963). $^{2}$ A.W. Richardson, R.W. Redding and J.C.D Brand, J. Mol. Spectroscopy, 29, 93 (1969).Author Institution:High dispersion absorption spectra of $^{35}ClO_{2}$ have been photographed in the region 4800 - 4300 {\AA}, with the $ClO_{2}$ gas held at dry ice temperature. Complete rotational analyses have been performed for the 000-000, 010-000 and 002-000 bands, and partial analyses have been possible for bands of the upper state stretching progression, $v_{1}00-000$ where $v_{1} = 1 - 5$. The upper state centrifugal distortion constants and the positions of various vibrational Coriolis perturbations give strong evidence that the vibrational level structure of the upper state antisymmetric stretching vibration $\nu_{3}^{\prime}$ is anomalous, and that there is a sizeable double minimum in the $Q_{3}^{\prime}$ coordinate. This is in agreement with the conclusion of Coon, Cesani and $Loyd^{1}$, but contrasts with that of Richardson, Redding and $Brand^{2}$. The upper state vibrational levels are all predissociated, and there are interesting variations of the line widths with rotation, vibration and spin state