Anisotropy of the angular distribution of fragment ions in dissociative double photoionization of N2O molecules in the 30-50 eV energy range

The double photoionization of N2O molecules by linearly polarized light in the 30–50 eV energy range has been studied by coupling ion imaging technique and electron-ion-ion coincidence. For the two possible dissociative processes, leading to N+ + NO+ and O+ + N2+, angular distributions of ionic fragments have been measured, finding an evident anisotropy. This indicates that the molecules ionize when their axis is parallel to the light polarization vector and the fragments are separating in a time shorter than the dication rotational period. The analysis of results provides, in addition to the total kinetic energy of ionic fragments, crucial information about the double photoionization dynamics.