si scf input card
 &control
    calculation='scf',
    restart_mode='from_scratch',
    prefix='si'
    pseudo_dir = '/home/lambert/espresso-4.2.1/pseudo',
    outdir='./tmp/'
 /
 &system
    ibrav = 2, celldm(1) =10.26, nat=  2, ntyp= 1,
    ecutwfc = 18.0, ecutrho
 /
 &electrons
    mixing_beta = 0.7
    conv_thr =  1.0d-8
 /
ATOMIC_SPECIES
 Si  28.086  Si.pbe-van_gipaw.upf
ATOMIC_POSITIONS
 Si -0.125 -0.125 -0.125
 Si  0.125  0.125  0.125
K_POINTS (automatic)
8 8 8 0 0 0