Basic input file

As explained on the abinit website you will need 3 basic input files (For computing the (pseudo) total energy, and some associated quantities):

    1. An input file
    2. A file containing the name of all your input files with extension *.files

A pseudopotential input file for each kind of element in the unit cell

Sample input file:

# In this input file, the location of the information on this or that line
# is not important : a keyword is located by the parser, and the related
# information should follow. 
# The "#" symbol indicates the beginning of a comment : the remaining
# of the line will be skipped.

#Definition of the unit cell
acell 10 10 10    # The keyword "acell" refers to the
                  # lengths of the primitive vectors (in Bohr)
#rprim 1 0 0  0 1 0  0 0 1 # This line, defining orthogonal primitive vectors,
                           # is commented, because it is precisely the default value of rprim

#Definition of the atom types
ntypat 1          # There is only one type of atom
znucl 1           # The keyword "znucl" refers to the atomic number of the 
                  # possible type(s) of atom. The pseudopotential(s) 
                  # mentioned in the "files" file must correspond
                  # to the type(s) of atom. Here, the only type is Hydrogen.

#Definition of the atoms
natom 2           # There are two atoms
typat 1 1         # They both are of type 1, that is, Hydrogen
xcart             # This keyword indicates that the location of the atoms
                  # will follow, one triplet of number for each atom
  -0.7 0.0 0.0    # Triplet giving the cartesian coordinates of atom 1, in Bohr
   0.7 0.0 0.0    # Triplet giving the cartesian coordinates of atom 2, in Bohr

#Definition of the planewave basis set
ecut 10.0         # Maximal plane-wave kinetic energy cut-off, in Hartree

#Definition of the k-point grid
kptopt 0          # Enter the k points manually 
nkpt 1            # Only one k point is needed for isolated system,
                  # taken by default to be 0.0 0.0 0.0

#Definition of the SCF procedure
nstep 10          # Maximal number of SCF cycles
toldfe 1.0d-6     # Will stop when, twice in a row, the difference 
                  # between two consecutive evaluations of total energy 
                  # differ by less than toldfe (in Hartree) 
                  # This value is way too large for most realistic studies of materials
diemac 2.0        # Although this is not mandatory, it is worth to
                  # precondition the SCF cycle. The model dielectric
                  # function used as the standard preconditioner
                  # is described in the "dielng" input variable section.
                  # Here, we follow the prescriptions for molecules 
                  # in a big box
# add to conserve old < 6.7.2 behavior for calculating forces at each SCF step
 optforces 1

Examples *.files file:


Where the first line is the name of your input file. The second line is the name of your output file. The third line is the prefix name to an input charge density file. The fourth line is the prefix name to an output charge density file. The fifth line is the tmp files. Finally line 6 and above are the pseudopotential files.

More information

The official Abinit help files can be found here.