Using Gaussian98
b3pw91/6-311g(d) scf=(direct,dsymm,symm) symm=loose fopt

Optimized Structure

 0.000000    3.128895   -0.935472
 3.120735   -1.976657    1.149192
 1.926264    0.000000   -1.971153
-3.120735   -1.976657    1.149192
 0.000000   -3.128895   -0.935472
-1.926264    0.000000   -1.971153
-3.120735    1.976657    1.149192
 0.000000    0.000000    1.216484
 3.120735    1.976657    1.149192

                    Distance matrix (angstroms):
                    1          2          3          4          5
     1  Ca   0.000000
     2  Ca   6.336519   0.000000
     3  Ca   3.817475   3.882072   0.000000
     4  Ca   6.336519   6.241471   6.254273   0.000000
     5  Ca   6.257790   3.925871   3.817475   3.925871   0.000000
     6  Ca   3.817475   6.254273   3.852529   3.882072   3.817475
     7  Ca   3.925871   7.388142   6.254273   3.953314   6.336519
     8  Ca   3.797486   3.694684   3.724450   3.694684   3.797486
     9  Ca   3.925871   3.953314   3.882072   7.388142   6.336519
                    6          7          8          9
     6  Ca   0.000000
     7  Ca   3.882072   0.000000
     8  Ca   3.724450   3.694684   0.000000
     9  Ca   6.254273   6.241471   3.694684   0.000000

SCF Done:  E(RB+HF-PW91) =  -6097.81539305 au

E(9 atoms of Calcium) = -6097.588045 au

Binding Energy = 6.1865 ev (0.6874 ev/atom)