MATRIX-ISOLATED FEO, NIO, AND COO - GROUND-STATE VIBRATIONAL FREQUENCIES

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 54Fe16O, 54Fe18O, 56Fe16O, 56Fe18O, 58Ni16O, 58Ni18O, 60Ni16O, 60Ni18O, 59Co16O, and 59Co18O were measured. The derived vibrational constants are: we = 880.02 ± 1.2 and wexe = 3.47 ± 0.6 cm-1 for 56Fe16O; we = 837.61 ± 1.1 and wexe = 5.92 ± 0.6 cm-1 for 58Ni16O; and we = 853.75 ± 1.2 and wexe = 3.65 ± 0.6 cm-1 for 59Co16O. These results support the assignment of 5Σ+ as the ground state of FeO, 3Σ- as the ground state of NiO, and 4Σ- as the ground state of CoO. © 1979.