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_PBE13
C C5.0-s1p1 C_PBE13
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)