Resonance energies of the Cl II-[3s 2 3p 3 ( 2 D 5/2 )]nd and [3s 2 3p 3 ( 2 P 3/2 )]nd, Ar II-3s 2 3p 4 ( 1 D 2 )ns, nd and of the Kr II [4s 2 4p 4 ( 1 D 2 )]ns, nd and 4s 2 4p 4 ( 3 P 2 , 3 P 1 )]ns, 4s 2 4p 4 ( 3 D 2 )]ns, nd and 4s 2 4p 4 ( 3 D 2 , 1 S 0 )]ns, nd Rydberg series are reported. Natural widths of the Ar II-[3s 2 3p 4 ( 1 D 2 )]ns, nd series are also reported. Calculations are done in the framework of the Modified Atomic Orbital Theory (MAOT). Excellent agreements are obtained with available theoretical and experimental data. High lying accurate resonance energies up to n = 40 are tabulated. The possibility to use the MAOT formalism report rapidly with an excellent accuracy the position of the excitation resonances as well as their width within simple analytical formulae is demonstrated.