[CPMD-list] help

[Pinilla Castellanos Carlos]

hi, all

I trying of optimize the parameter of red in Si, my input file is
&CPMD
RESTART WAVEFUNCTIONS LATEST	
OPTIMIZE WAVEFUNCTION
SPLINE
5000
&END
&SYSTEM
  SYMMETRY
   1
 CELL
11.0      1.0     1.0     0.0     0.0     0.0
 CUTOFF
 40.
SCALE
TESR
4 4 4
&END
&ATOMS
*SI_SGS KLEINMAN-BYLANDER
 LMAX=P
  8
       0.0	0.0	0.0
	0.5	0.5	0.0
	0.5	0.0	0.5
	0.0	0.5	0.5
	0.25	0.25	0.25
	0.25	0.75	0.75
	0.75	0.25	0.75
	0.75	0.75	0.25	
&END
&DFT
FUNCTIONAL DFT
&END
&END
the result is a=5.6784 Angstrom and the theory the Si parameter is 5.43 A,
how can i better the result parameter?

thanks for your help

Carlos