(Si)8  (Fd-3m) ~ Si  (VASP)
    1.0
            0.00000000 2.70931500 2.70931500 
            2.70931500 0.00000000 2.70931500 
            2.70931500 2.70931500 0.00000000 
  Si
  2
Direct
        0.37500000 0.37500000 0.37500000      	#	1      	Si
        0.62500000 0.62500000 0.62500000      	#	2      	Si