Rotational spectroscopy of AlO: Low N transitions of astronomical interest in the X^2 Sigma^+ state

The detection of rotational transitions of the AlO radical at millimeter wavelengths from an astronomical source has recently been reported. In view of this, rotational transitions in the ground X^2 Sigma^+ state of AlO have been reinvestigated. Comparisons between Fourier transform and microwave data indicate a discrepancy regarding the derived value of gamma_D in the v = 0 level of the ground state. This discrepancy is discussed in the light of comparisons between experimental data and synthesized rotational spectra in the v = 0, 1 and 2 levels of X^2 Sigma^+. A list of calculated rotational lines in v = 0, 1 and 2 of the ground state up to N = 11 is presented which should aid astronomers in analysis and interpretation of observed AlO data and also facilitate future searches for this radical.