The energy dependence of total cross sections of reactions 6 He + Si and 6,9 Li + Si in the beam energy range 5-30 MeV/nucleon has been measured. An agreement with the published experimental data for the reaction 6 He + Si was obtained. For the reaction 9 Li + Si new data in the vicinity a local enhancement of the total cross section was obtained. Theoretical analysis of possible reasons of appearance of this peculiarity in the collisions of nuclei 6 He and 9 Li with Si nuclei has been carried out including the influence of external neutrons of weakly bound projectile nuclei.

Experimental cross sections for formation of isotopes 44,46 Sc-in reaction ( 3 He + 45 Sc), 46 Sc-in reaction ( 6 He + 45 Sc), 65 Zn-in reaction ( 3 He + 64 Zn), 196,198 Au-in reactions ( 6 He + 197 Au) have been analyzed within the TDSE approach for the external neutrons of 3,6 He, 45 Sc and 197 Au nuclei. Fusion-evaporation was taken into account using the NRV evaporation code. Results of calculation demonstrate overall satisfactory agreement with the experimental data.