The low-lying electronic states of FeO¿: Rotational analysis of the resonance enhanced photodissociation spectra

The resonance enhanced ~111! photodissociation spectra of the ~8,0! and ~9,0! bands of the P7/2←S system of FeO have been recorded. From a rotational analysis, the rotational parameters for the S ground state of FeO have been obtained for the first time. The rotational constant B050.502060.0004 cm 21 is derived, giving r051.64360.001 Å. Other molecular parameters determined for the S ground state are the spin–spin coupling constant, l520.12660.006 cm, and the spin–rotational coupling constant, g520.03360.002 cm. The assignment of the upper state as P7/2 is based on the characteristic appearance of the band and on time-dependent density functional ~TD-DFT! calculations performed on FeO. The reliability of the TD-DFT method in the prediction of excited states of FeO is corroborated by calculations on CrF and MnO, which have been extensively characterized either by spectroscopy or by high-level theoretical calculations. © 2003 American Institute of Physics. @DOI: 10.1063/1.1615521#