Ab initio study of band strengths for the F2Σ+–A2Π electronic transition of AlO

Ab initio calculations of band strengths have been carried out for the F2Σ+–A2Π electronic transition of the AlO molecule. The band strength for the 0-0 band, the only band observed, is the largest of the 56 calculated bands. The band strengths for unobserved 19 bands are of the same order of magnitude as the 0-0 band, including the 1-0 and 2-1 bands whose observations are expected to lead to experimental determination of the vibrational constants for the F2Σ+ state. The Einstein coefficients for spontaneous emission of the F–A bands have been evaluated from the present band strengths and transition energies, and are used to estimate the ratios of the populations in those initial vibrational states, which produce 1-0 and 2-1 bands not weaker in intensity than the detectable 0-0 band, to the population that produces the detectable band.