Knowledge Bank

We have generated MgNC in supersonic free jet expansions, and measured the laser induced fluorescence excitation spectra of the vibronic bands of the $A~\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi -X~\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ transition. We have found some new features in the spectra, though part of the spectra were already reported by Wright and $Millera$. The new features are consisting of the $\nu 2$ bending vibronic bands. From the rotational analyses of some of the vibronic bands, we have obtained information on the vibronic structure of the $A~\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi$ state of MgNC. The assignments of the $\nu 2$ vibronic bands were carried out utilizing the vibrational analyses of the dispersed fluorescence spectra obtained by the excitation of the $\nu 2$ vibronic bands. On the basis of the vibrational structures of the dispersed fluorescence spectra which are not only those of the $\nu 2$ vibronic bands but also the spectra obtained by the excitation of the other vibronic bands reported by $usb$, the vibronic structure of the $X~\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ state of MgNC has been analysed. The vibronic structures of the $A~2\Pi$ and $X~\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ states of MgNC will be discussed comparing with the computational results by Hirano $groupc$.