Knowledge Bank

On our SiCN/SiNC experiment}, TC02 (2005).}, we measured laser induced fluorescence excitation spectrum in the range, 27,500 $\sim$ 33,000 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$, under jet cooled condition. Some of the vibronic bands in the spectrum have been assigned to Si containing species, such as Si$2$, SiCH$2$, SiCN, and SiNC, but some remain unassigned. The strongest band among them has a $2\Pi$ -- $2\Pi$ type rotational structure. The rotational constants of the ground and excited states are determined to be about 0.11 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$, and they are about half of those of SiCN and SiNC. The spin-orbit interaction constant is determined to be 141.7 and 2.7 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ for the ground and excited states, respectively. Those are comparable with 140.8 and 4.9 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ for the $X~$ $2\Pi$ and $A~$ $2\Delta$ states of SiCN (~not SiNC~), respectively. As a result of some discussion, we have finally conclude that the spectrum can be attributed to the $2\Delta$ -- $X~$ $2\Pi$ transition of Si--N--Si. The $2\Sigma +$ -- $X~$ $2\Pi$ transition of Si$2$N was studied by two groups} \underline{267}, 370 (1997).}}, MG05 (2002).}. The rotational constant of the ground $X~$ $2\Pi$ state agrees with that of the previous work. The vibronic structure of the laser induced fluorescence excitation spectrum is unusual; the $2\Sigma$ -- $2\Pi$ type vibronic bands have been only identified.