THE C-N STRETCHING VIBRONIC BANDS OF THE MgNC $\tilde{A} {^{2}}\Pi - \tilde{X}{^{2} \Sigma^{+}}$ TRANSITION

Abstract

We have generated MgNC in supersonic free jet expansions, and measured the laser induced fluorescence excitation spectra of the C-N stretching vibronic bands of the $\tilde{A}{^{2}}\Pi - \tilde{X}{^{2}}\Sigma^{+}$ transition. Rotational analysis yields the molecular constants of the vibronic levels, (1,0,0) and (1,0,1), in the $\tilde{A}{^{2}}\Pi$ state. The vibronic levels, (0,0,0), (0,1,0), and (0,0,1), were already analyzed by $Wright and Miller^{a}$. We can not find any anomalies in the constants of the C-N stretching vibronic levels, while they are predicted to be lying above the barrier of the isomerization reaction pathway, MgNC $\leftrightarrow$ MgCN, on the $\tilde{A}{^{2}}\Pi$ state. On the basis of the molecular constants obtained, we discuss the fine structures of both the ground $\tilde{X}{^{2}\Sigma^{+}}$ and excited $\tilde{A}{^{2}}\Pi$ states.