HIGH RESOLUTION LASER SPECTROSCOPY OF EXCITED BENDING VIBRATIONS $(\nu_{2} \leq 2)$ OF THE $B^{2}\Sigma^{+}$ AND $X^{2}\Sigma^{+}$ ELECTRONIC STATES OF SrOH: ANALYSIS OF $\ell$-TYPE DOUBLING AND $\ell$-TYPE RESONANCE

Abstract

The $(02^{0}0)-(000), (02^{2}0)-(01^{1}0), (02^{0}0)-(01^{1}0), (01^{1}0)-(000), (02^{0}0)-(02^{0}0)$, and $(02^{2}0)-(02^{2}0)$ bands of the $B^{2}\Sigma^{+} - X^{2}\Sigma^{+}$ system of SrOH have been observed and rotationally analyzed using CW dye laser excitation and resolved fluorescence. Data from all transitions were included in a global least-squares fit. The effects of a weak $\ell$-type resonance between the $\ell = 0$ and $\ell = 2$ components of the $\nu_{2} = 2$ vibrational level were observed in both electronic states, and the off-diagonal matrix elements were evaluated in a case (b) basis. A previous $analysis^{1}$ of the $B^{2}\Sigma+(01^{1}0)\Pi$ level, which attributes anamalous $\ell$-type doubling to an electronic perturbation arising from the $A^{2}\Pi(010)$ polyad is inconsistent with our experimental results.