[en] The diffusion of the particles has by the light cores that present a weak gate of potential, must permit the survey of the nuclear strengths. Some authors, studying the distribution in energy of the protons given out by a hydrogenated target submitted to a bombardment has variable energy, signal that this distribution has a structure of groups. We tried to reproduce experiences of diffusion α-proton, in order to verify the existence of the groups of signaled protons in the previous works. However in spite of finer experimental conditions, we had recovered any group structures in the distribution of the protons. This work permits to conclude that there is not a resonance in the α-proton diffusion for included energies between 3,1 and 5,3 MeV. The absence of resonances confirms the existence of the fundamental level of ⁵Li above in the neighborhood of 1,8 MeV ⁴He + ¹H. (M.B.)