Systematics of the Coulomb barrier characteristics resulting from M3Y nucleon-nucleon forces for reactions with heavy ions

In the literature, often the capture cross sections for spherical heavy-ions are calculated by virtue of the characteristics of the s-wave barrier: its energy, radius, and stiffness. We evaluate these quantities systematically within the framework of the double-folding model. For the effective nucleon-nucleon forces, the M3Y Paris forces with zero-range exchange part are used. The strength of this part is modified to fit the barrier energy obtained with the density-dependent finite-range exchange part. For the nucleon density, two options are employed. The first one (V-option) is based on the experimental charge densities. The second one, C-option, comes from the IAEA data base; these densities are calculated within the Hartree-Fock-Bogolubov approach. For both options, the analytical approximations are developed for the barrier energy, radius, and stiffness. The accuracy of these approximations is about 3$\%$ for the barrier energy and radius and about 10$\%$ for the stiffness. The proposed approximations can be easily used by everyone to estimate the capture cross sections within the parabolic barrier approximation.