THE LOW-LYING BENDING VIBRONIC BANDS OF THE MgNC $\tilde{A}$ $^2\Pi$ -- $\tilde{X}$ $^2\Sigma^+$ TRANSITION: ANALYSIS OF THE RENNER-TELLER VIBRONIC STRUCTURE

Abstract

We have generated MgNC in supersonic free jet expansions, and measured the laser induced fluorescence excitation spectra of the Mg-N-C bending vibronic bands of the $\tilde{A}$ $^2\Pi$ -- $\tilde{X}$ $^2\Sigma^+$ transition. We analyzed $2_0^1$, $\kappa$ $^2\Sigma^{(+)}$ -- and $2_0^2$, $\kappa$ $^2\Pi$ -- $^2\Sigma^+$ bands and $2_0^2$, $\mu$ $^2\Pi_{\frac{1}{2}}$ -- $^2\Sigma^+$ sub-band. Through the molecular constants of the $\tilde{A}$ (010) $\kappa$ $^2\Sigma^{(+)}$, (020) $\kappa$ $^2\Pi$ and $\mu$ $^2\Pi_{\frac{1}{2}}$ levels, the Renner-Teller vibronic structure on the $\nu_2$ bending mode in the $\tilde{A}$ $^2\Pi$ state has been characterized. To analyze the vibronic structure, we need to consider the anharmonic term.