The electron impact excitation cross section for resonance transitions of Be+ and Mg+ is calculated by the diagonalisation method. The energies, effective quantum numbers, total and partial widths of resonances in cross sections are obtained. The partial and differential cross sections were also obtained. The total cross sections were compared with experiment and other calculations.

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The spin -spin mass splitting of light, heavy and mixed mesons are described within a good accuracy in the potential model with screened potential. We conclude that the long -distance part of the potential cannot be pure scalar and that a vector -scalar mixture is favoured. With the same parameters which gives correct average mass spectrum excellent spin -spin splittings of heavy quarkonia is obtained. The results are obtained by going beyond usually used perturbation method, namely using configuration interaction approach.

Electron impact excitation of the Ca atoms from the metastable 4s4p 3 P J states has been studied by an optical method in crossed atomic and electron beams in the energy range from threshold up to 30 eV. The relative excitation functions and the absolute values of the emission cross sections for 16 spectral transitions excited both from the metastable and ground states have been obtained. The experimental results are compared with the close-coupling and Born-Ochkur calculations carried out with the extensive many-configuration target wavefunctions. In most cases the theoretical excitation functions agree within the limits of experimental error (50%) with the experimental results including the resonance-like structure in the near-threshold region allowing us to classify uniquely the resonances observed.