Effect of electric fields on the decay branching ratio of P-1(e) doubly excited states in helium measured by time-resolved fluorescence

Resonant Auger spectra following O 1s−1u excitation of metastable oxygen a 1g molecules have been measured at high resolution under resonant Raman conditions. By selectively monitoring various decay channels, the singlet manifold excitation spectrum has been separated from the dominating triplet excitation. The decay spectra have been analyzed using the lifetime-vibrational-interference model to give the spectroscopic parameters of the 1s excited 1u state of O2. Singlet and triplet manifold Auger decay rates are also compared.