Strong impact of the giant resonance on the radiationless decay of the 4d vacancy in Xe: I. Decay of the 4d super(9)np resonances

The influence of the interchannel interaction on the radiationless decay of the Xe 4d super(9)np resonances is found to be extremely large due to the potential barrier effect. Interaction between the 5s5p-4d epsilon f and 5p5p-4d epsilon g decay channels reduces the decay transition amplitude associated with the outgoing g wave by a factor of about 3. The effect is confirmed by the good agreement between computed and measured photoionization cross sections and polarization parameters of the Xe 5p super(4)mp levels.