State-selected ion photodissociation

Using the optical optical double resonance (O.O.D.R.) technique, Na2 molecules in a supersonic beam are ionized in well defined v J levels of the Na2 + X 2∑ u + ground state. These ions are then laser photodissociated as a function of the previously prepared vibrational level. As a result, we determine the potential curve of the first Na2 + 2Π u state. Dipole moment transition and photodissociation cross-sections are also calculated.