Different methods have been applied in order to determine the ionic assignment of spectral lines. Several techniques have been developed: from classical methods, where excitation energy is increased to observe the emitted radiation from consecutive ions [1] - [7] , to the more recent ones, like the determination of energy level lifetimes (8) or plasma electronic density measurements (9) . All of these methods must be considered as complementary and, due to that reason, the results cannot be derived a priori in opposition to experimental data or interpretation.