Brief Introduction of the Input Files
The following files are the central input files for ABACUS. Before executing the program, please make sure these files are prepared and stored in the working directory. Here we give some simple descriptions. For more details, users should consult the Advanced session. The Below is an example The parameter list always starts with key word Any line starting with Each parameter value is provided by specifying the name of the input variable and then putting the value after the name, separated by one or more blank characters(space or tab). The following characters (> 150) in the same line will be neglected. Depending on the input variable, the value may be an integer, a real number or a string. The parameters can be given in any order, but only one parameter should be given per line. Furthermore, if a given parameter name appeared more than once in the input file, only the last value will be taken. Note: if a parameter name is not recognized by the program, the program will stop with an error message. In the above example, the meanings of the parameters are: For a complete list of input parameters, please consult this instruction. Note: Users cannot change the filename “INPUT” to other names. Boolean paramerters such as The structure file contains structural information about the system, e.g., lattice constant, lattice vectors, and positions of the atoms within a unit cell. The positions can be given either in direct or Cartesian coordinates. An example of the Note: users may choose a different name for their structure file using the keyword For a more detailed description of STRU file, please consult here. This file contains information of the kpoint grid setting for the Brillouin zone sampling. An example of the Note: users may choose a different name for their k-point file using keyword For a more detailed description, please consult here. The pseudopotential files Norm-conserving pseudopotentials are used in ABACUS, in the UPF file format.The filename of each element’s pseudopotential needs to be specified in the STRU file, together with the directory of the pseudopotential files unless they are already present in the working directory. More information on pseudopotentials is given here. The numerical orbital files This part is only required in LCAO calculations. The filename for each element’s numerical orbital basis needs to be specified in the STRU file, together with the directory of the orbital files unless they are already present in the working directory. ABACUS provides numerical atomic basis sets of different accuracy levels for most elements commonly used. Users can download these basis sets from the website. Moreover, users can generate numerical atomic orbitals by themselves, and the procedure is provided in this short introduction.INPUT
INPUT
file contains parameters that control the type of calculation as well as a variety of settings.INPUT
file with some of the most important parameters that need to be set:INPUT_PARAMETERS
suffix MgO
ntype 2
pseudo_dir ./
orbital_dir ./
ecutwfc 100 # Rydberg
scf_thr 1e-4 # Rydberg
basis_type lcao
calculation scf # this is the key parameter telling abacus to do a scf calculation
out_chg True
INPUT_PARAMETERS
. Any content before INPUT_PARAMETERS
will be ignored.#
or /
will also be ignored.suffix
: the name of the system, default ABACUS
ntype
: how many types of elements in the unit cellpseudo_dir
: the directory where pseudopotential files are providedorbital_dir
: the directory where orbital files are providedecutwfc
: the plane-wave energy cutoff for the wave function expansion (UNIT: Rydberg)scf_thr
: the threshold for the convergence of charge density (UNIT: Rydberg)basis_type
: the type of basis set for expanding the electronic wave functionscalculation
: the type of calculation to be performed by ABACUSout_chg
: if true, output thee charge density oon real space gridout_chg
can be set by using True
and False
, 1
and 0
, or T
and F
. It is case insensitive so that other preferences such as true
and false
, TRUE
and FALSE
, and t
and f
for setting boolean values are also supported.STRU
STRU
file is given as follows :#This is the atom file containing all the information
#about the lattice structure.
ATOMIC_SPECIES
Mg 24.305 Mg_ONCV_PBE-1.0.upf # element name, atomic mass, pseudopotential file
O 15.999 O_ONCV_PBE-1.0.upf
NUMERICAL_ORBITAL
Mg_gga_8au_100Ry_4s2p1d.orb
O_gga_8au_100Ry_2s2p1d.orb
LATTICE_CONSTANT
1.8897259886 # 1.8897259886 Bohr = 1.0 Angstrom
LATTICE_VECTORS
4.25648 0.00000 0.00000
0.00000 4.25648 0.00000
0.00000 0.00000 4.25648
ATOMIC_POSITIONS
Direct #Cartesian(Unit is LATTICE_CONSTANT)
Mg #Name of element
0.0 #Magnetic for this element.
4 #Number of atoms
0.0 0.0 0.0 0 0 0 #x,y,z, move_x, move_y, move_z
0.0 0.5 0.5 0 0 0 #x,y,z, move_x, move_y, move_z
0.5 0.0 0.5 0 0 0 #x,y,z, move_x, move_y, move_z
0.5 0.5 0.0 0 0 0 #x,y,z, move_x, move_y, move_z
O #Name of element
0.0 #Magnetic for this element.
4 #Number of atoms
0.5 0.0 0.0 0 0 0 #x,y,z, move_x, move_y, move_z
0.5 0.5 0.5 0 0 0 #x,y,z, move_x, move_y, move_z
0.0 0.0 0.5 0 0 0 #x,y,z, move_x, move_y, move_z
0.0 0.5 0.0 0 0 0 #x,y,z, move_x, move_y, move_z
stru_file
. The order of the pseudopotential file list and the numerical orbital list (if LCAO is applied) MUST be consistent with that of the atomic type given in ATOMIC_POSITIONS
.KPT
KPT
file is given below:K_POINTS
0
Gamma
4 4 4 0 0 0
kpoint_file