Using Gaussian98
b3pw91/6-311g(d) scf=direct fopt

Optimized Structure

-1.488593    0.000627    1.694803
 3.920833   -1.949048   -0.855704
 0.548771    3.126427    0.790428
-2.617119    1.945078   -1.370747
 3.922215    1.947709   -0.855380
-5.276913   -0.000546    0.499038
 2.367141   -0.000180    2.003408
 0.547870   -3.126028    0.790956
-2.616646   -1.944534   -1.371021
 0.692441    0.000496   -1.325781


                    Distance matrix (angstroms):
                    1          2          3          4          5
     1  Ca   0.000000
     2  Ca   6.290327   0.000000
     3  Ca   3.839190   6.311973   0.000000
     4  Ca   3.801586   7.627208   4.011124   0.000000
     5  Ca   6.290581   3.896757   3.934232   6.559611   0.000000
     6  Ca   3.972559   9.498975   6.618268   3.788938   9.500216
     7  Ca   3.868065   3.792963   3.814900   6.325488   3.792781
     8  Ca   3.839282   3.933657   6.252455   6.356589   6.311849
     9  Ca   3.802030   6.557759   6.356600   3.889612   7.627066
    10  Ca   3.725700   3.800554   3.777622   3.838829   3.800573
                    6          7          8          9         10
     6  Ca   0.000000
     7  Ca   7.790680   0.000000
     8  Ca   6.616793   3.814540   0.000000
     9  Ca   3.788566   6.324983   4.010515   0.000000
    10  Ca   6.242048   3.726677   3.778443   3.838651   0.000000
    
SCF Done:  E(RB+HF-PW91) =  -6775.35265704 au

E(10 atoms of Calcium) = -6775.0978286 au

Binding Energy = 6.9343 ev (0.69343 ev/atom)