S6 = 0.9724690738;  sig7 := 0.3; 
    ad := Sqrt[8/3];  k7 = 1.0; z = 54;
T = 9. *k7/R7^2;
Vee = 
        12. *sig7/R7 + 368. /(S6 + R7) + 
          24. *ad/(S6 + R7);
Vne = -8.0*z/(S6 + R7);
S7 = R7*4^(1/3);
func = T + Vee + Vne;
t = 
      FindMinimum[
        func, {R7, 
          1.5}, {Method -> Automatic}, {MaxIterations -> 
            500}]
N[Vne  /. t[[2]], 10]
N[Vee  /. t[[2]], 10]
N[-(Vee + Vne)/T  /. t[[2]], 10]