Three-photon ionisation spectra of strontium in the excitation range 5560-5640 AA

Abstract

The three-photon ionisation of strontium atoms via resonance in the last photon absorption with some autoionising states was observed in the excitation range 5560-5640 AA using a tunable dye laser. The spectra as a function of the laser intensity are reported. Very rapid line broadening and ion enhancement together with very asymmetric line profiles are observed.