An input file 'Methane.dat' in the directory 'work' is shown below. The input file has a flexible data format in such a way that a parameter is given behind a keyword, the order of keywords is arbitrary, and a blank and a comment can be also described freely. For the keywords and options, both capital, small letters, and the mixture are acceptable, although these options in below example are written in a specific form.
# # File Name # System.CurrrentDirectory ./ # default=./ System.Name met level.of.stdout 1 # default=1 (1-3) level.of.fileout 1 # default=1 (0-2) # # Definition of Atomic Species # Species.Number 2 <Definition.of.Atomic.Species H H5.0-s1 H_PBE19 C C5.0-s1p1 C_PBE19 Definition.of.Atomic.Species> # # Atoms # Atoms.Number 5 Atoms.SpeciesAndCoordinates.Unit Ang # Ang|AU <Atoms.SpeciesAndCoordinates 1 C 0.000000 0.000000 0.000000 2.0 2.0 2 H -0.889981 -0.629312 0.000000 0.5 0.5 3 H 0.000000 0.629312 -0.889981 0.5 0.5 4 H 0.000000 0.629312 0.889981 0.5 0.5 5 H 0.889981 -0.629312 0.000000 0.5 0.5 Atoms.SpeciesAndCoordinates> Atoms.UnitVectors.Unit Ang # Ang|AU <Atoms.UnitVectors 10.0 0.0 0.0 0.0 10.0 0.0 0.0 0.0 10.0 Atoms.UnitVectors> # # SCF or Electronic System # scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE scf.SpinPolarization off # On|Off|NC scf.ElectronicTemperature 300.0 # default=300 (K) scf.energycutoff 120.0 # default=150 (Ry) scf.maxIter 100 # default=40 scf.EigenvalueSolver cluster # DC|Cluster|Band scf.Kgrid 1 1 1 # means n1 x n2 x n3 scf.Mixing.Type rmm-diis # Simple|Rmm-Diis|Gr-Pulay|Kerker|Rmm-Diisk scf.Init.Mixing.Weight 0.30 # default=0.30 scf.Min.Mixing.Weight 0.001 # default=0.001 scf.Max.Mixing.Weight 0.400 # default=0.40 scf.Mixing.History 7 # default=5 scf.Mixing.StartPulay 5 # default=6 scf.criterion 1.0e-10 # default=1.0e-6 (Hartree) # # MD or Geometry Optimization # MD.Type nomd # Nomd|Opt|NVE|NVT_VS|NVT_NH # Constraint_Opt|DIIS MD.maxIter 1 # default=1 MD.TimeStep 1.0 # default=0.5 (fs) MD.Opt.criterion 1.0e-4 # default=1.0e-4 (Hartree/Bohr)