Knowledge Bank

The Infrared vibrational spectra of the FeO, NiO, and CoO molecules have been observed in Ar matrices at 14 K. Frequencies for each of the isotopomers $\mathrm{<mrow\; data-mjx-texclass="ORD">54</mrow>}Fe16O,54Fe18O,56Fe16O,56Fe18O,58Ni16O,58Ni18O,60Ni16O,60Ni18O,59Co16O$, and $\mathrm{<mrow\; data-mjx-texclass="ORD">59</mrow>}Co18O$, were measured.. The derived vibrational constants are: \begin{eqnarray*} \omega_{e} &=& 880.02 \pm 1.2 ; and ; \omega_{e}x_{e} = 3.47 \pm 0.6; cm^{-1} ; for; ^{54}Fe^{16}O;\ \omega_{e} &=& 837.61 \pm 1.1 ; and ; \omega_{e}x_{e} = 5.92 \pm 0.6; cm^{-1} ; for ; ^{50}Ni^{16}O;\ and;; \omega_{e} &=& 853.75 \pm 1.2 ; and ; \omega_{e}x_{e} = 3.65 \pm 0.6; cm^{-1} ; for ; ^{59}Co^{16}O.\ \end{eqnarray*} These results support the assignment of $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Sigma +$ as the ground state of FeO, $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma -$ as the ground state of NiO, and $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Sigma -$ as the ground state of CoO.