Knowledge Bank

A band system or systems have been observed in the 3p triatomic nitride $Si_{2}N $ in the spectral region $33.000cm-1-36.000cm-1$ using resonant two-photon ionization spectroscopy. An upper limit of 8 2 eV is placed on the ionization energy of $Si2N$. Rotational analysis of the most intense band shows it to be a $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma a\to 2\Pi g$ transition consistent with a linear centrosymmetric structure. The lower and upper state bond lengths have been determined as $r20(Si-N,X2\Pi g)=1.6395\pm 0.0014\backslash AA$ and $r01(Si-N,2\Sigma u1)=1.6343\pm 0.0015\backslash AA$. The ground state assignment and bend length are consistent with those calculated by Boldyrev and Simons (personal communication). The molecular orbital configuration is presented ad comparison is made to the isovalent 2p analogue, CNC.