Structure

# Element: structure

This element contains all structural information, such as unit-cell parameters as well as type and position of each atom. The presence of the subelement species is necessary unless one wants to perform an empty-lattice calculation. The attribute speciespath must be specified.

 contains: crystal (required) species (optional) XPath: /input/structure

This element allows for specification of the following attributes: speciespath (required), autormt, cartesian, epslat, primcell, rmtapm, tshift

## Attribute: autormt

If "true", the muffin-tin radius of each species is automatically set according to the variables specified by the attribute rmtapm.

 Type: boolean Default: "false" Use: optional XPath: /input/structure/@autormt

## Attribute: cartesian

If "true" the input atomic positions are given in cartesian coordinates.

 Type: boolean Default: "false" Use: optional XPath: /input/structure/@cartesian

## Attribute: epslat

This attribute defines the accuracy up to which two vectors can be considered numerically identical. Vectors with lengths less than this are considered zero.

 Type: fortrandouble Default: "1.0d-6" Use: optional Unit: Bohr XPath: /input/structure/@epslat

## Attribute: primcell

If "true", the primitive unit cell is determined automatically from the conventional cell defined by the basis vectors given by the basevect elements. The primitive unit cell is determined by searching for lattice vectors among all vectors connecting atomic sites and choosing the three shortest ones which produce a unit cell with non-zero volume.

 Type: boolean Default: "false" Use: optional XPath: /input/structure/@primcell

## Attribute: rmtapm

This attribute assigns the two parameters governing the automatic generation of the muffin-tin radii. When the attribute autormt is set to "true", the muffin-tin radii are determined according to the following expression

(1)
\begin{align} R_i\propto 1+\zeta|Z_i|^{1/3}, \end{align}

where $Z_i$ is the atomic number of the $i$ th species, $\zeta$ is stored in rmtapm(1). The distance between the muffin-tin speheres is determined by the value of rmtapm(2): When rmtapm(2)=1, the closest muffin-tin spheres will touch each other.

 Type: vect2d Default: "0.25d0 0.95d0" Use: optional XPath: /input/structure/@rmtapm

## Attribute: speciespath

The path to the directory containing the species files. Alternatively, it can be defined as an HTTP URL, in this case the wget utility must be installed.

 Type: anyURI Use: required XPath: /input/structure/@speciespath

## Attribute: tshift

If "true", the crystal is shifted such that the atom closest to the origin is exactly at the origin.

 Type: boolean Default: "true" Use: optional XPath: /input/structure/@tshift

# Element: crystal

Defines the unit cell of the crystal via the 3 basis vectors.

 contains: basevect (required) XPath: /input/structure/crystal

This element allows for specification of the following attributes: scale, stretch

## Attribute: scale

Scales all the lattice vectors by the same factor. This is useful for varying the volume.

 Type: fortrandouble Default: "1.0d0" Use: optional Unit: 1 XPath: /input/structure/crystal/@scale

## Attribute: stretch

Allows for an individual scaling of each lattice vector separately. "1 1 1" means no scaling.

 Type: vect3d Default: "1.0d0 1.0d0 1.0d0 " Use: optional XPath: /input/structure/crystal/@stretch

# Element: basevect

Defines one basis vector in Cartesian coordinates.

 Type: vect3d Unit: Bohr XPath: /input/structure/crystal/basevect

# Element: species

Defines the atomic species, i.e., the chemical element. Aatomic coordinates and, optionally, quantities relevant for magnetic calculations are defined in the subelement(s) atom.

 contains: atom (required) LDAplusU (optional) dfthalfparam (optional) XPath: /input/structure/species

This element allows for specification of the following attributes: speciesfile (required), rmt

## Attribute: rmt

Defines the muffin-tin radius. This optional parameter allows to override the value either specified in the species file or generated by automatic determination. The muffin-tin radius defines the region around the atomic nucleus where the wave function is expanded in terms of atomic-like functions. In contrast, the interstitial region, i.e., the region not belonging to any muffin-tin sphere, is described by planewaves.

 Type: fortrandouble Default: "-1.0d0" Use: optional Unit: Bohr XPath: /input/structure/species/@rmt

## Attribute: speciesfile

Defines the file that contains the species definition. It is looked up in the species directory specified by speciespath. By default, the name of the file is element.xml, e.g., Ag.xml.

 Type: anyURI Use: required XPath: /input/structure/species/@speciesfile

# Element: atom

Defines the position and other attributes of one atom in the unit cell.

 Type: no content XPath: /input/structure/species/atom

This element allows for specification of the following attributes: coord (required), bfcmt, lockxyz, mommtfix

## Attribute: bfcmt

Muffin-tin external magnetic field in Cartesian coordinates.

 Type: vect3d Default: "0.0d0 0.0d0 0.0d0" Use: optional XPath: /input/structure/species/atom/@bfcmt

## Attribute: coord

Atom position in lattice coordinates.

 Type: vect3d Use: required Unit: lattice coordinates XPath: /input/structure/species/atom/@coord

## Attribute: lockxyz

Switches to constrain atomic movement along x/y/z directions.

 Type: booleantriple Default: "false false false" Use: optional XPath: /input/structure/species/atom/@lockxyz

## Attribute: mommtfix

The desired muffin-tin moment for a Fixed Spin Moment (FSM) calculation.

 Type: vect3d Default: "0.0d0 0.0d0 0.0d0" Use: optional XPath: /input/structure/species/atom/@mommtfix

# Element: LDAplusU

The LADplusU element is used to specify the J, U, and l parameters of an atomic species. To switch on the LDAplusU feature one needs to set the ldapu attribute of the groundstate element.

 Type: no content XPath: /input/structure/species/LDAplusU

This element allows for specification of the following attributes: J, U, l

## Attribute: J

 Type: fortrandouble Default: "0.0d0" Use: optional XPath: /input/structure/species/LDAplusU/@J

## Attribute: U

 Type: fortrandouble Default: "0.0d0" Use: optional XPath: /input/structure/species/LDAplusU/@U

## Attribute: l

 Type: integer Default: "-1" Use: optional XPath: /input/structure/species/LDAplusU/@l

# Element: dfthalfparam

This element specifies some of the fundamentals parameters (for each species) regarding a DFT-1/2 calculation. Do not forget to specify the subelement dfthalf inside the element groundstate, otherwise no DFT-1/2 correction will be done (even though you specify the parameters).

 contains: shell (required) XPath: /input/structure/species/dfthalfparam

This element allows for specification of the following attributes: ampl, cut, exponent

## Attribute: ampl

Specifies the amplitude of the self-energy potential.

 Type: fortrandouble Default: "1.00" Use: optional XPath: /input/structure/species/dfthalfparam/@ampl

## Attribute: cut

Specifies the value of $r_{\rm cut}$ (in Bohrs) for the self-energy potential, which determines the range of the correction. Note that this can/should be specified for each species.

 Type: fortrandouble Default: "0.0d0" Use: optional Unit: Bohr XPath: /input/structure/species/dfthalfparam/@cut

## Attribute: exponent

Specifies the exponent $n$ of the cutoff-function (for the self-energy potential)

(2)
\begin{align} \Theta (r) = A\left[1-\left(\frac{r}{r_{\rm cut}} \right)^{\!\!n} \right]^3 \nonumber \end{align}

for $r \le r_{\rm cut}$.

 Type: integer Default: "8" Use: optional XPath: /input/structure/species/dfthalfparam/@exponent

# Element: shell

This element specifies the shell to which the DFT-1/2 correction should be applied to.

 Type: no content XPath: /input/structure/species/dfthalfparam/shell

This element allows for specification of the following attributes: ionization, number

## Attribute: ionization

Specifies the degree of ionization.

 Type: fortrandouble Default: "0.5d0" Use: optional Unit: Bohr XPath: /input/structure/species/dfthalfparam/shell/@ionization

## Attribute: number

Specifies the number of the shell to be ionized. For instance, a number equal to 1 will ionize the first shell, a number equal to 2, the second, and so on. The default value of 0 corresponds to the last shell specified in the species file.

 Type: integer Default: "0" Use: optional XPath: /input/structure/species/dfthalfparam/shell/@number

# Reused Elements

The following elements can occur more than once in the input file. There for they are listed separately.

# Data Types

The Input definition uses derived data types. These are described here.