RESONANCE-ENHANCED MULTIPHOTON IONIZATION OF THE SIF RADICAL - A REINVESTIGATION

We report multiphoton ionisation spectra of ground (X(2) Pi) state SiF radicals, resonance enhanced at the two-photon energy by the v' = 1 l evel of the C ''(2) Sigma(+) excited state, at much higher resolution than hitherto. An earlier suggestion by Dulcey and Hudgens that the an omalous intensity of the C ''-X (1.0) two-photon transition might be a ttributable to additional, accidental, resonance enhancement at the on e-photon energy by levels of the A(2) Sigma(+) v' = 0 state is confirm ed, and the double resonance enhancement analysed in detail. A similar accidental double resonance enhancement, involving levels of the A(2) Sigma(+), v' = 1 state at the one-photon energy, is proposed to expla in the observed fragmentary pattern of lines associated with the C'(2) Pi-X (5,0) two-photon transition.