Photodouble ionization of He with circularly polarized synchrotron radiation: complete experiment and dynamic nodes

The combination of measurements of the photodouble ionization ( PDI) of He with linearly and circularly polarized synchrotron radiation has allowed to obtain experimentally the moduli and relative phase of the complex amplitudes needed for the complete description of the process. The same quantities have been used to calculate other observables of the process ( linear dichroism, asymmetry parameter of the angular distribution of one of the two photoelectrons and He2+ recoil momentum distribution). Moreover, the present measurements prove definitely the existence of the dynamic nodes predicted by theories in the circular dichroism of PDI and associate them to a reduction of dimensionality of the process.