Systematics in the volume integrals of the imaginary part of the alpha-nucleus optical potentials

From a systematic analysis of the imaginary part of the alpha-nucleus phenomenological optical model potentials covering a large range of mass numbers and energies, it has been shown that the volume integral per target-projectile pair increases with increase of energy and saturates to a value in the neighborhood of 100 MeV fm 3 at higher energies. Interestingly, this value is in remarkable agreement with those obtained using nucleons, deuterons, 3 He, and t, as projectiles.