Knowledge Bank

Approximate ab initio wave functions for the TiN molecule were calculated by the method of Roothaan to investigate the electronic structure, spectra, and ground state symmetry of the molecule. This molecule is of interest for comparison with the isoelectronic molecule ScO, which has been shown to have a $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ ground state, contrary to experimental interpretation. Furthermore, it is of interest in delineating the structure and bonding of comparable nitride molecules and solid phases of the transition elements. Only indirect experimental evidence for the existence of TiN is available from the work of Parkinson and $Reeves.1$ In the matrix Hartree-Fock approximation, the molecule is just sufficiently stable in the region of equilibrium separation to enable reliable calculations to be carried out for the two configurations, $\pi 3\sigma 2(2\Pi )$ and $\pi 4\sigma (2\Sigma +)$. These states are near degenerate, and the former appears to be the ground state. Effects of configuration interaction, direct electron correlation contributions, and estimates of the molecular properties will be discussed.