MILLIMETER-WAVE SPECTROSCOPY OF VIBRATIONALLY EXCITED GROUND-STATE ALKALINE-EARTH HYDROXIDE RADICALS (X(2)SIGMA(+))

Pure rotational spectra of the alkaline-earth monohydroxides have been recorded for vibrationally excited states (0 1 0), (0 2 0), (0 3 0), and (1 0 0) of the ground electronic state (X 2Σ+) using millimeter-wave absorption spectroscopy. The radicals MgOH, CaOH, SrOH, and BaOH were studied. The data for CaOH, SrOH, and BaOH were analyzed with a linear 2Σ+ model, but with the addition of two terms to account for contamination of the υ2 = 1 2Π and υ2 = 2 2Δ vibronic levels with 2Π and 2Δ electronic states. The data for MgOH, however, did not fit well to this linear model and is additional evidence that this species is quasilinear. © 1995 American Institute of Physics.