Knowledge Bank

The infrared, visible, and near-ultraviolet spectra of TiO, ZrO, HfO, WO, $WO2$ (and $WO3,W2O6,W3O8,W3O9$) have been observed in neon and argon matrices at $4\circ$ and $20\circ K$ with $\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O$ substitution. A discussion will be given of the spectra and the molecular orbitals and ground states of the diatomic and triatomic molecules. The larger tungsten oxide molecules have been observed in the infrared only; the particular trapped species varying with the conditions of vaporization. It is found that (1) the spectra confirm a $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Delta \ast \ast \ast$ ground state for $TiO,1$ (2) ZrO, and probably HfO, have a $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +$ ground state, (3) the $W16O$ electronic spectra exhibit many vibrational perturbations not present in the $W18O$ spectra, (4) the $WO2$ spectra are like those of $TaO2$, so that $WO2$ is bent in the ground and excited $states,2$ (5) each of the numerous infrared bands of the $WaOm$ molecules can usually be assigned to particular species with the help of mass spectrometric $data.3\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$ J. G. Phillips, Astrophys, J. 115, 567 (1962). $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ W. Weltner, Jr. and D. McLeod, Jr., J. Chem. Phys. 42, 882 (1965). $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$ J. Berkowitz, W. A. Chupka, M. G. Inghram, J. Chem. Phys. 27, 85 (1957); R. J. Ackermann and E. G. Rauh, J. Phys. Chem. 67, 2596 (1963).