&control
    calculation='md'
    dt=20,
    nstep=50
 /
 &system
    ibrav= 2, celldm(1)=10.18, nat=  2, ntyp= 1,
    ecutwfc = 8.0, nosym=.true.
 /
 &electrons
    conv_thr =  1.0e-8
    mixing_beta = 0.7
 /
 &ions
    wfc_extrapolation='first_order'
 /
ATOMIC_SPECIES
 Si  28.086  Si.pz-vbc.UPF
ATOMIC_POSITIONS
 Si -0.123 -0.123 -0.123
 Si  0.123  0.123  0.123
K_POINTS {automatic}
 1 1 1 0 0 0