MICROWAVE-SPECTRUM OF THE NIO RADICAL IN THE X(3)SIGMA(-) STATE

The microwave spectrum of NiO in the (3) Sigma(-) electronic ground st ate has been observed using a source-modulated millimeter and submilli meter wave spectrometer. NiO was generated by de-sputtering vaporizati on of powdered NiO. Rotational transitions of (NiO)-Ni-58 and (NiO)-Ni -60 in the vibronic ground state were measured in the 110-460 GHz regi on and those of (NiO)-Ni-58 in the upsilon = 1 state in the 240-370 GH z region. Precise molecular constants were obtained by a least-squares analysis of the measured frequencies. The r(e) bond length is obtaine d to be 1.6271291(31) Angstrom with three standard errors in parenthes es.