$$ (15) #links# The actual kind associated with force might be indicated with all the Hellman-Feynman pressure in ith nucleus: $$ mathbfF_i=mathbfF_i^n-n +int rho left( mathbfr right) cdot boldsymbolupvarepsilon_ileft( mathbfr right)dmathbfr;mathrmwhere;boldsymbolupvarepsilon_ileft( mathbfr right)=-fracZ_ileft( mathbfR_i-mathbfr right) mathbfR_i-mathbfr right^3. $$ (O