CaOH AND CaOD: VIBRONIC COUPLING AND THE RENNER-TELLER EFFECT

Abstract

The $\tilde{C}^{2}\Delta-\tilde{X}^{2}\Sigma^{+}$ transitioin of CaOH and CaOD has been observed in the blue region of the spectrum. This electronically forbidden transition becomes allowed through vibronic coupling with the bending mode. The (010)--(000) band for CaOH and the (010)--(000), (020)--(010), (010)--(010)(000)--(010), and (010)--($02^{\circ}0$) bands for CaOD have been recorded and analyzed at high resolution. The $\tilde{C}^{2}\Delta$ (000) state of CaOD has a band origin at $21907.128(1)cm^{-1}$, a rotational constant B of $0.293536(7)cm^{-1}$ and a spin-orbit constant A of $11.4944(5)cm^{-1}$. A ratational analysis of the $\tilde{C}^{2}\Delta(020)\mu\Sigma$ and the $\tilde{C}^{2}\Delta(020)\kappa\Sigma$ states has also led to the first experimental determination of the Renner-Teller parameter ${g}_{4}$ for a $^{2}\Delta$ state or $0.03862(9) cm^{-1}$.