&control
 calculation='scf'
 tprnfor=.true.
 tstress=.true.
/
&system
 ibrav=4
 celldm(1)=4.66
 celldm(3)=2.60
 nat=4
 ecutwfc=18.
 ecutrho=200.
 ntyp=1
 occupations='smearing'
 degauss=0.02
 smearing='marzari-vanderbilt'
 input_dft='vdw-DF-c09'
/
&electrons
 mixing_beta=0.5
 mixing_ndim=20
/
ATOMIC_SPECIES
 C   12.   C.pbe-van_bm.UPF   1
K_POINTS {gamma}
ATOMIC_POSITIONS {crystal}
 C      0.00000    1.00000    0.75000 
 C      0.66667    0.33333    0.75000 
 C      0.00000    1.00000    0.25000
 C      0.33333    0.66667    0.25000