Electronic transition moment of the AlO(B 2Σ+−X 2Σ+) emission. Analysis of the R dependence of the Al2+O2− character in the X 2Σ+ state

The dependence of the electronic transition moment, Re(R), of the AlO(B 2Σ+−X 2Σ+) system on the internuclear distance, R, has been determined by an analysis of the intensity distribution of the emission spectra as Re(R) = [1–2.29(13)(R/Å−1.5)2] (1.510 Å Å ⩽ R ⩽ 1.9836 Å). The R dependences of Re(R) and the X 2Σ+ ≈ A 2∏i off-diagonal spin-orbit interaction matrix element, HelSO(R), have been analyzed simultaneously to evaluate the R dependence of the Al2+O2− character in the X 2Σ+ state and that of the orbital exponent of the oxygen atom. The results agree with the theoretical prediction by Lengsfield and Liu (J. Chem. Phys. 77 (1982) 6083) that the charge-transfer process, Al2+O2− → Al+O− takes place in the range of 1.6 Å ⪅ R ⪅ 2.1 Å.