&CONTROL
  calculation		 =	 'vc-relax',
  title			 =	 '1X1_sn',
  verbosity		 =	 'high',
  restart_mode		 =	 'from_scratch',
  outdir		 =	 './TEMP/',
  prefix		 =	 'sn_geo',
  pseudo_dir		 =	 './',
  
! Switch to default value while NOT performing calculations related to geomtry optimisation, default value = 1
  nstep			=	50,

! Use this parameter(=.true) while doing calculations related to geometry optimisation via vc-relax
  tstress		=	.true,

! Use these parameters while doing calculations related to geometry optimisations
  tprnfor		=	.true,
  dt			=	20.D,
  etot_conv_thr		=	1.0D-4
  forc_conv_thr		=	1.0D-3

/
&SYSTEM
  ibrav			=	4,
  celldm(1)		=	8.84391826296449,
  celldm(3)		=	4.27350427350427
  nat			=	2,
  ntyp			=	1,
  ecutwfc		=	65,

/
&ELECTRONS
  diagonalization	=	'david',
  conv_thr		=	1D-6
  mixing_mode		=	'plain',
  mixing_beta		=	0.7D0,

/
&IONS
! Use these parameters while doing calculations related to geometry optimisation 
  ion_dynamics		=	'bfgs',

/
&CELL
! Use these parameters while doing calculations related to geometry optimisation or vc-relax
  cell_dofree		=	'shape',

/
ATOMIC_SPECIES
	Sn	0.0	Sn.pbe-dn-kjpaw_psl.0.2.UPF

ATOMIC_POSITIONS {crystal}
Sn      0.32543800000000      0.67456200000000      0.51816200000000
Sn      0.67456200000000      0.32543800000000      0.48183800000000

K_POINTS {automatic}
21  21  1   1 1 1 

