15min:

MASARU FUKUSHIMA AND TAKASHI ISHIWATA, Faculty of Information Sciences, Hiroshima City University, Asa-Minami, Hiroshima 731-3194, Japan.

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 A ² - X ^{2 +} transition. Rotational analysis yields the molecular constants of the vibronic levels, (1,0,0) and (1,0,1), in the A ² state. The vibronic levels, (0,0,0), (0,1,0), and (0,0,1), were already analyzed by Wright and Miller. 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 MgCN, on the A ² state. On the basis of the molecular constants obtained, we discuss the fine structures of both the ground X ^{2 +} and excited A ² states.