SYSTEM = H2O vibration

PREC = Accurate  ! recommended for computing forces
ENCUT = 520
ISMEAR = 0    
SIGMA = 0.1

IBRION = 8    ! finite differences with symmetry
NFREE = 2     ! central differences (default)
POTIM = 0.015 ! step size (default)

EDIFF = 1E-8  ! convergence criterion
NSW = 1       ! ionic steps > 0
