The energy per particle in a nuclear system characterized by a total density ρ(sum of the neutron and proton densities ρn and ρp),and by a local asymmetry δ≡(ρn-ρp)/ρ,is usually written asEA(ρ,δ)=E/A(ρ,δ=0)+ S(ρ)δ2.(1)Odd powers of δ are forbidden by the isospin symmetry and the term proportional to δ4 is found to be negligible.The above equation defines the so-called symmetry energy S(ρ).Determining the values of the symmetry energy at various densities The energy per particle in a nuclear system characterized by a total density ρ (sum of the neutron and proton densities ρn and ρp), and by a local asymmetry δ ≡ (ρn-ρp) / ρ, is usually written as EA (ρ, δ ) = E / A (ρ, δ = 0) + S (ρ) δ2. (1) Odd powers of δ are forbidden by the isospin symmetry and the term proportional to δ4 is found to be negligible. -called symmetry energy S (ρ) .Determining the values ​​of the symmetry energy at various densities