Infrared diode laser spectroscopy of the LiO radical

The fundamental vibrational band of the 7LiO radical in the ground electronic state X 2Πi was observed in a region from 720 to 850 cm−1 using a source frequency modulation infrared diode laser spectrometer. Radicals were generated in a high-temperature cell by the reaction of lithium metal vapor with nitrous oxide. The observed spectrum was analyzed together with the radio-frequency and microwave spectra already reported. It was found that the vibration-rotation Hamiltonian employed in a previous paper was insufficient to fit all of the observed spectra simultaneously. The Hamiltonian was thus extended to include higher-order corrections for the centrifugal distortion and Λ-type doubling terms, and was used to derive molecular parameters.