Perturbations in the angular distribution of photoelectrons from laser-aligned Na atoms

Using linearly polarized laser and synchrotron radiation for the investigation of the autoionizing resonances Na 1=2p53s3p we found for one of these resonances (2p5(3s3p 3P)2P32/ at 31.5 eV) a strong perturbation in the angular distribution of the photoelectrons. We explain this effect by the loss of electronic alignment due to the hyperfine coupling with the nuclear spin during the autoionization process.