The infrared spectrum of NiCO isolated in solid argon has been reinves
tigated. Isotopic data on nu(1), nu(2), nu(3), 2 nu(1), nu(1), nu(2) a
nd nu(1) + nu(3) have been measured in the near-and far-infrared regio
ns. This enables a complete harmonic force-field calculation based on
the assumption of a linear geometry. Comparisons with bond force const
ants of Ni(CO)(4) and the latest ab initio predictions of the NiCO vib
rational frequencies are also presented. (C) 1998 Elsevier Science B.V
.