Charge and energy dependences of ionization and transfer for helium in collisions with fast charged projectiles

The classical method within the independent electron model is employed to investigate (i) charge dependences of single and double ionization for helium by various charged ions A(q+) (q = 1 - 8) at impact energies of 0.64 and 1.44 MeV/u, respectively, (ii) energy dependences of transfer ionization for helium by 0.5-3 MeV/u A(8,9+) ions impact. The Lenz-Jensen model of the atom is applied instead of the Bohr model of the atom, and the impact-parameter dependences are also introduced into the calculations. Satisfactory agreement is found between theoretical and experimental data.