Input Reference

Table of Contents

<title>

<atom>

<Root> input

The input element Is the root element of the exciting input file. XML may contain only one root element. The Input element must contain one structure element and one groundstate element.

Attributes:

xsltpath
(/input/@xsltpath)

type: xs:anyURI
default-value: ../../xml

scratchpath
(/input/@scratchpath)
This is the path to scratch space where the eigenvector files EVECFV.OUT, EVECSV.OUT and OCCSV.OUT will be written. If the local directory is accessed via a network then scrpath can be set to a directory on a local disk

type: xs:anyURI
use: optional

id
(/input/@id)
The id is a unique identifier in an input set. The inputset element is currently not used by the exciting code.

type: xs:ID

depends
(/input/@depends)
The depends attribute can be used to specify a dependence from another simulation in the same input set. The inputset element is currently not used by the exciting code.

type: xs:IDREFS

<title>

Title of the input file.

<structure>

The structure element contains all structural information such as atoms atom positions and symmetries.

Attributes:

speciespath
(/input/structure/@speciespath)
gives the path to the directory containing the species files

type: xs:anyURI
use: required

molecule
(/input/structure/@molecule)
has to be set to true if one wants to calculate an isolated molecule. is true , then the atomic positions, ${\bf a}$ , are assumed to be in Cartesian coordinates. The lattice vectors are also set up automatically with the i-th lattice vector given by

(1)

${\bf A}^i=A_i\hat{\bf e}^i,$

where

(2)

$A_i=\max_{\alpha,\beta}\left|{\bf a}^{\alpha}_i-{\bf a}^{\beta}_i\right| +d_{\rm vac}$

with $\alpha$ and $\beta$ labeling atoms, and $d_{\rm vac}$ determines the size of the vacuum around the molecule. The last variable is set by the attribute vacuum .

type: xs:boolean
default-value: false

vacuum
(/input/structure/@vacuum)
determines the size of the vacuum around the molecule.

type: fortrandouble
default-value: 10

epslat
(/input/structure/@epslat)
vectors with lengths less than this are considered zero.

type: fortrandouble
default-value: 1e-6

autormt
(/input/structure/@autormt)
If true automatic determination of the muffin tin radii is allowed.

type: xs:boolean
default-value: false

primcell
(/input/structure/@primcell)
allows the primitive unit cell to be determined automatically from the conventional cell. This is done by searching for lattice vectors among all those which connect atomic sites, and using the three shortest ones which produce a unit cell with non-zero volume.

type: xs:boolean
default-value: false

tshift
(/input/structure/@tshift)
Set to it to "true" if the crystal can be shifted such that the atom closest to the origin is exactly at the origin.

type: xs:boolean
default-value: true

<crystal>

defines the unit cell of the calculation.

Attributes:

scale
(/input/structure/crystal/@scale)
scales all the lattice vectors. This is useful for varying the volume.

type: fortrandouble
default-value: 1

stretch
(/input/structure/crystal/@stretch)
allows for a separate scaling of each lattice vector. 1 1 1 means no scaling.

type: vect3d
default-value: 1.0d0 1.0d0 1.0d0

<basevect>

are the basis vectors or lattice vectors in Bohr.

<species>

for each atom type (species) a species element is defined containing all the atom positions

Attributes:

speciesfile
(/input/structure/species/@speciesfile)
defines the file from which the species definition is read. It is looked up in the species directory specified by the species path.

type: xs:anyURI
use: required

chemicalSymbol
(/input/structure/species/@chemicalSymbol)
can be given to simplify visualisation and converters. is ignored by exciting

type: xs:string
use: optional
default-value:

atomicNumber
(/input/structure/species/@atomicNumber)
can be given to simplify visualisation and converters. is ignored by exciting

type: xs:integer
use: optional

rmt
(/input/structure/species/@rmt)
muffin tin radius this optional parameter allows to override speciesfile or automatic tetemination

type: fortrandouble
use: optional
default-value: -1

<atom>

atomic position in lattice coordinates for atom

Attributes:

coord
(/input/structure/species/atom/@coord)
position in lattice coordinates

type: vect3d

bfcmt
(/input/structure/species/atom/@bfcmt)
muffin-tin external magnetic field in Cartesian coordinates for atom

type: vect3d
default-value: 0 0 0

mommtfix
(/input/structure/species/atom/@mommtfix)

type: vect3d

<LDAplusu>

If present defines ldaplusU parameters for species

Attributes:

L
(/input/structure/species/LDAplusu/@L)

type: fortrandouble
default-value: 0

U
(/input/structure/species/LDAplusu/@U)

type: fortrandouble
default-value: 0

J
(/input/structure/species/LDAplusu/@J)

type: fortrandouble
default-value: 0

<groundstate>

The groundstate element is required for anny calculation. Its attributes are the parameters and methods used to calculate the groundstate density.

Attributes:

do
(/input/groundstate/@do)
Decides if the groundstate is read from file or recalculated or continued from file.

type: select:

fromscratch
fromfile
skip

default-value: fromscratch

ngridk
(/input/groundstate/@ngridk)
Number of k grid points along the basis vector directions.

type: integertriple
use: required

rgkmax
(/input/groundstate/@rgkmax)
This sets the maximum length for the ${ \bf G}+{ \bf k}$ vectors, defined as rgkmax divided by the smallest muffin-tin radius.

type: fortrandouble
default-value: 7

epspot
(/input/groundstate/@epspot)
If the RMS change in the effective potential and magnetic field is smaller than epspot, then the self-consistent loop is considered converged and exited. For structural optimisa- tion runs this results in the forces being calculated, the atomic positions updated and the loop restarted. See also maxscl.

type: fortrandouble
use: optional
default-value: 1e-6

rmtapm
(/input/groundstate/@rmtapm)
parameters governing the automatic generation of the muffin-tin radii. When @autormt is set to true, the muffin-tin radii are found automatically from the formula

(3)

$R_i\propto 1+\zeta|Z_i|^{1/3},$

where $Z_i$ is the atomic number of the $i$th species, $\zeta$ is stored in @rmtapm(1) and the value which governs the distance between the muffin-tins is stored in @rmtapm(2). When @rmtapm(2) =1, the closest muffin-tins will touch.

type: vect2d
default-value: 0.25d0 0.95d0

swidth
(/input/groundstate/@swidth)
width of the smooth approximation to the Dirac delta function.

type: fortrandouble
default-value: 0.001d0

stype
(/input/groundstate/@stype)
A smooth approximation to the Dirac delta function is needed to compute the occupancies of the Kohn-Sham states. The variable swidth determines the width of the approximate delta function.

type: select:

Gaussian
Methfessel-Paxton 1
Methfessel-Paxton 2
Fermi Dirac
Square-wave impulse

default-value: Gaussian

findlinentype
(/input/groundstate/@findlinentype)
select method to determine the linearization energies.

type: select:

simple
advanced

default-value: advanced

isgkmax
(/input/groundstate/@isgkmax)
species for which the muffin-tin radius will be used for calculating gkmax.

type: xs:integer
default-value: -1

gmaxvr
(/input/groundstate/@gmaxvr)
maximum length of |G| for expanding the interstitial density and potential.

type: fortrandouble
default-value: 12

nempty
(/input/groundstate/@nempty)
Defines the number of eigenstates beyond that required for charge neutrality. When running metals it is not known // a priori //how many states will be below the Fermi energy for each-point. Setting nempty greater than zero allows the additional states to act as a buffer in such cases. Furthermore, magnetic calculations use the first-variational eigenstates as a basis for setting up the second-variational Hamiltonian, and thus nempty will determine the size of this basis set. Convergence with respect to this quantity should be checked.

type: xs:integer
default-value: 5

nosym
(/input/groundstate/@nosym)
when set to .true. no symmetries, apart from the identity, are used anywhere in the code.

type: xs:boolean
default-value: false

frozencore
(/input/groundstate/@frozencore)
when set to true the frozen core approximation is applied, i.e., the core states are fixed to the atomic states.

type: xs:boolean
default-value: false

autokpt
(/input/groundstate/@autokpt)
if the-point set is to be determined automatically

type: xs:boolean
default-value: false

radkpt
(/input/groundstate/@radkpt)
Used for the automatic determination of the-point mesh. If autokpt is set to true then the mesh sizes will be determined by $n_i=\lambda/|{ \bf A}_i|+1$ .

type: fortrandouble
default-value: 40

reducek
(/input/groundstate/@reducek)
reducek set to true if the $k$ -point set is to be reduced with the crystal symmetries.

type: xs:boolean
default-value: true

tfibs
(/input/groundstate)
[see] Because calculation of the incomplete basis set (IBS) correction to the force is fairly time- consuming, it can be switched off by setting tfibs to .false. This correction can then be included only when necessary, i.e. when the atoms are close to equilibrium in a structural relaxation run.

tforce
(/input/groundstate)
[see] if the force should be calculated at the end of the self-consistent cycle.

lmaxapw
(/input/groundstate/@lmaxapw)
angular momentum cut-off for the APW functions.

type: xs:integer
default-value: 10

maxscl
(/input/groundstate/@maxscl)
upper limit for te selfconsistency loop.

type: xs:integer
default-value: 200

chgexs
(/input/groundstate/@chgexs)
This controls the amount of charge in the unit cell beyond that required to maintain neu-trality. It can be set positive or negative depending on whether electron or hole doping is required.

type: fortrandouble
default-value: 0

deband
(/input/groundstate/@deband)
initial band energy step size The initial step length used when searching for the band energy, which is used as the APW linearisation energy. This is done by first searching upwards in energy until the radial wavefunction at the muffin-tin radius is zero. This is the energy at the top of the band, denoted $E_{\rm t}$ . A downward search is now performed from $E_{\rm t}$ until the slope of the radial wavefunction at the muffin-tin radius is zero. This energy, $E_{\rm b}$ , is at the bottom of the band. The band energy is taken as $(E_{\rm t}+E_{\rm b})/2$ . If either $E_{\rm t}$ or $E_{\rm b}$ cannot be found then the band energy is set to the default value.

type: fortrandouble
default-value: 0.0025d0

epschg
(/input/groundstate/@epschg)
maximum allowed error in the calculated total charge beyond which a warning message will be issued.

type: fortrandouble
default-value: 1.0d-3

epsocc
(/input/groundstate/@epsocc)
smallest occupancy for which a state will contribute to the density.

type: fortrandouble
default-value: 1e-8

mixer
(/input/groundstate/@mixer)
select the mixing (relaxation) scheme for SCF

type: select:

lin
msec
pulay

default-value: msec

beta0
(/input/groundstate/@beta0)
initial value for mixing parameter. Used in linear mixing.

type: fortrandouble
default-value: 0.4

betainc
(/input/groundstate/@betainc)
mixing parameter increase. Used in linear mixing.

type: fortrandouble
default-value: 1.1

betadec
(/input/groundstate/@betadec)
mixing parameter decrease. Used in linear mixing.

type: fortrandouble
default-value: 0.6

lradstep
(/input/groundstate/@lradstep)
Some muffin-tin functions (such as the density) are calculated on a coarse radial mesh and then interpolated onto a fine mesh. This is done for the sake of efficiency. lradstp defines the step size in going from the fine to the coarse radial mesh. If it is too large, loss of precision may occur.

type: xs:integer
default-value: 4

nprad
(/input/groundstate/@nprad)
smallest occupancy for which a state will contribute to the density.

type: xs:integer
default-value: 4

xctype
(/input/groundstate/@xctype)
type of exchange-correlation functional to be used \begin{itemize} \item No exchange-correlation funtional ( $E_{\rm xc}\equiv 0$ ) \item LDA, Perdew-Zunger/Ceperley-Alder, {\it Phys. Rev. B}, 5048 (1981) \item LSDA, Perdew-Wang/Ceperley-Alder, // Phys. Rev. B //, 13244 (1992) \item LDA, X-alpha approximation, J. C. Slater, // Phys. Rev. //, 385 (1951) \item LSDA, von Barth-Hedin, // J. Phys. C //, 1629 (1972) \\ \item GGA, Perdew-Burke-Ernzerhof, // Phys. Rev. Lett. //, 3865 (1996) \item GGA, Revised PBE, Zhang-Yang, {\it Phys. Rev. Lett.}, 890 (1998) \item GGA, PBEsol, arXiv:0707.2088v1 (2007) \item GGA, Wu-Cohen exchange (WC06) with PBE correlation, // Phys. Rev. B //, 235116 (2006) \item GGA, Armiento-Mattsson (AM05) spin-unpolarised functional, {\it Phys. Rev. B}, 085108 (2005) \end{itemize}

type: select:

LDAPerdew-Zunger
LSDAPerdew-Wang
LDA-X-alpha
LSDA-Barth-Hedin
GGAPerdew-Burke-Ernzerhof
GGArevPBE
GGAPBEsol
GGA-Wu-Cohen
GGAArmiento-Mattsson
EXX
none

default-value: LSDAPerdew-Wang

evalmin
(/input/groundstate/@evalmin)
Any valence states with eigenvalues below evalmin are not occupied and a warning message is issued.

type: fortrandouble
default-value: -4.5d0

lmaxvr
(/input/groundstate/@lmaxvr)
angular momentum cut-off for the muffin-tin density and potential.

type: xs:integer
default-value: 6

fracinr
(/input/groundstate/@fracinr)
fraction of the muffin-tin radius up to which lmaxinr is used as the angular momentum cut-off.

type: fortrandouble
default-value: 0.25d0

lmaxinr
(/input/groundstate/@lmaxinr)
Close to the nucleus, the density and potential is almost spherical and therefore the spherical harmonic expansion can be truncated a low angular momentum. See also fracinr.

type: xs:integer
default-value: 2

lmaxmat
(/input/groundstate/@lmaxmat)
angular momentum cut-off for the outer-most loop in the hamiltonian and overlap matrix setup.

type: xs:integer
default-value: 5

vkloff
(/input/groundstate/@vkloff)
the k-point offset vector in lattice coordinates.

type: vect3d
default-value: 0 0 0

npsden
(/input/groundstate/@npsden)

type: xs:integer
default-value: 9

cfdamp
(/input/groundstate/@cfdamp)
damping coefficient for characteristic function.

type: fortrandouble
default-value: 0

nosource
(/input/groundstate/@nosource)
when set to true, source fields are projected out of the exchange-correlation magnetic field. experimental feature.

type: xs:boolean
default-value: false

tevecsv
(/input/groundstate/@tevecsv)
tevecsv is true if second-variational eigenvectors are calculated

type: xs:boolean
default-value: false

nwrite
(/input/groundstate/@nwrite)
Normally, the density and potentials are written to the file STATE.OUT only after com- pletion of the self-consistent loop. By setting nwrite to a positive integer the file will be written during the loop every nwrite iterations.

type: xs:integer
default-value: 0

ptnucl
(/input/groundstate/@ptnucl)
ptnucl is true if the nuclei are to be treated as point charges, if .false. ! the nuclei have a finite spherical distribution.

type: xs:boolean
default-value: true

<spin>

If present calculation is done with spin polarization it may be switched of with the spinpol attribute set to false

Attributes:

momfix
(/input/groundstate/spin/@momfix)
the desired total moment for a FSM calculation.

type: vect3d
default-value: 0 0 0

bfieldc
(/input/groundstate/spin/@bfieldc)
alows to apply a constant B field This is a constant magnetic field applied throughout the entire unit cell and enters the second-variational Hamiltonian as

(4)

$\frac{g_e\alpha}{4}\,\vec{\sigma}\cdot{\bf B}_{\rm ext},$

where $g_e$ is the electron $g$ -factor (2.0023193043718). This field is normally used to break spin symmetry for spin-polarised calculations and considered to be infinitesimal with no direct contribution to the total energy. In cases where the magnetic field is finite (for example when computing magnetic response) the external ${ \bf B}$ -field energy reported in INFO.OUT should be added to the total by hand. This field is applied throughout the entire unit cell. To apply magnetic fields in particular muffin-tins use the bfcmt vect ors in the atoms block. Collinear calculations are more efficient if the field is applied in the $z$ -direction.

type: vect3d
default-value: 0 0 0

spinorb
(/input/groundstate/spin/@spinorb)
if a spin-orbit coupling is required If spinorb is .true. , then a $\boldsymbol \sigma\cdot{ \bf L}$ term is added to the second-variational Hamiltonian. See spinpol .

type: xs:boolean

spinsprl
(/input/groundstate/spin/@spinsprl)
set to .true. if a spin-spiral calculation is require Experimental feature for the calculation of spin-spiral states. See vqlss for details.

type: xs:boolean

vqlss
(/input/groundstate/spin/@vqlss)
the ${ \bf q}$ -vector of the spin-spiral state in lattice coordinates Spin-spirals arise from spinor states assumed to be of the form

(5)

$\Psi^{ \bf q}_{ \bf k}({ \bf r})= \left( \begin{array}{c} U^{{\bf q}\uparrow}_{ \bf k}({\bf r})e^{i({ \bf k+q/2})\cdot{ \bf r}} \\ U^{{ \bf q}\downarrow}_{\bf k}({ \bf r})e^{i({\bf k-q/2})\cdot{ \bf r}} \\ \end{array} \right).$

These are determined using a second-variational approach, and give rise to a magnetisation density of the form

(6)

${\bf m}^{ \bf q}({ \bf r})=(m_x({\bf r})\cos({ \bf q \cdot r}), m_y({\bf r})\sin({ \bf q \cdot r}),m_z({\bf r})),$

where $m_x$ , $m_y$ and $m_z$ are lattice periodic. See also spinprl .

type: vect3d
default-value: 0 0 0

taufsm
(/input/groundstate/spin/@taufsm)

type: fortrandouble
default-value: 0.01d0

reducebf
(/input/groundstate/spin/@reducebf)
After each iteration the external magnetic fields are multiplied with reducebf. This al- lows for a large external magnetic field at the start of the self-consistent loop to break spin symmetry, while at the end of the loop the field will be effectively zero, i.e. infinitesimal. See bfieldc and atoms.

type: fortrandouble
default-value: 1

fixspin
(/input/groundstate/spin/@fixspin)

type: select:

none
total FSM
localmt FSM
both

default-value: none

<HartreeFock>

If preset HartreeFock calculation is triggered.

Attributes:

epsengy
(/input/groundstate/HartreeFock/@epsengy)
energy convergence tolerance

type: fortrandouble
use: optional
default-value: 1e-7

<solver>

Optional configuration options for eigenvector solver.

Attributes:

type
(/input/groundstate/solver/@type)
select the eigenvalue solver for the first variational equation

type: select:

Lapack
Arpack
DIIS

default-value: Lapack

packedmatrixstorage
(/input/groundstate/solver/@packedmatrixstorage)
In the default calculation the matrix is sored in packed form. When using multithreaded BLAS setting this parmeter to false increases efficiency.

type: xs:boolean
use: optional
default-value: true

epsarpack
(/input/groundstate/solver/@epsarpack)
Tolerance parameter for the ARPACK shift invert solver

type: fortrandouble
default-value: 1.0e-8

evaltol
(/input/groundstate/solver/@evaltol)
error tolerance for the first-variational eigenvalues using the LAPACK Solver

type: fortrandouble
default-value: 1e-8

<OEP>

If present exact exchange calculation is triggered. (experimental)

Attributes:

maxitoep
(/input/groundstate/OEP/@maxitoep)
maximum number of iterations when solving the exact exchange integral equations

type: xs:integer
default-value: 120

tauoep
(/input/groundstate/OEP/@tauoep)
The optimised effective potential is determined using an interative method. [Phys. Rev. Lett. 98, 196405 (2007)]. At the first iteration the step length is set to tauoep(1). Dur- ing subsequent iterations, the step length is scaled by tauoep(2) or tauoep(3), when the residual is increasing or decreasing, respectively. See also maxitoep.

type: vect3d
default-value: 1.0 0.2 1.5

<RDMFT>

If present Reduced Density Matrix Funcional Theory calculation is triggered

Attributes:

rdmxctype
(/input/groundstate/RDMFT/@rdmxctype)
xc functional.

type: xs:integer
default-value: 2

rdmmaxscl
(/input/groundstate/RDMFT/@rdmmaxscl)
maximum number of self-consistent loops.

type: xs:integer
default-value: 1

maxitn
(/input/groundstate/RDMFT/@maxitn)
maximum number of iteration for occupation number optimisation.

type: xs:integer
default-value: 250

maxitc
(/input/groundstate/RDMFT/@maxitc)
maximum number of iteration for natural orbital optimisation.

type: xs:integer
default-value: 10

taurdmn
(/input/groundstate/RDMFT/@taurdmn)
step size for occupation numbers.

type: fortrandouble
default-value: 1.0

taurdmc
(/input/groundstate/RDMFT/@taurdmc)
step size for natural orbital coefficients.

type: fortrandouble
default-value: 0.5

rdmalpha
(/input/groundstate/RDMFT/@rdmalpha)
exponent for the functional.

type: fortrandouble
default-value: 0.7

rdmtemp
(/input/groundstate/RDMFT/@rdmtemp)
temperature.

type: fortrandouble
default-value: 0.0

<structureoptimization>

The structure optimization element triggers if present a geometry relaxation.

Attributes:

epsforce
(/input/structureoptimization/@epsforce)
convergence tolerance for the forces during a structural optimisation run.

type: fortrandouble
default-value: 5e-5

tau0atm
(/input/structureoptimization/@tau0atm)
the step size to be used for structural optimisationThe position of atom $\alpha$ is updated on step $m$ of a structural optimisation run using

(7)

${\bf r}_{\alpha}^{m+1}={\bf r}_{\alpha}^m+\tau_{\alpha}^m \left({ \bf F}_{\alpha}^m+{ \bf F}_{\alpha}^{m-1}\right),$

where $\tau_{\alpha}$ is set to tau0atm for $m=0$ , and incremented by the same amount if the atom is moving in the same direction between steps. If the direction changes then $\tau_{\alpha}$ is reset to tau0atm .

type: fortrandouble
default-value: 0.2d0

resume
(/input/structureoptimization/@resume)
Resumption of structural optimisation run using density in STATE.OUT but with positions from exciting.in .

type: xs:boolean
default-value: false

<properties>

Properties listed in this element can be calculated from the groundstate. It works also from a saved state from a previous run.

<bandstructure>

If present a banstructure is calculated.

Attributes:

scissor
(/input/properties/bandstructure)
[see] value to shift bandgap.

character
(/input/properties/bandstructure/@character)
Band structure plot which includes angular momentum characters for every atom.

type: xs:boolean
default-value: false

exciting

all electron DFT

Home

Getting Started

Contact

Development

Releases

Events

<Root> input

Attributes:

<title>

<structure>

Attributes:

<crystal>

Attributes:

<basevect>

<species>

Attributes:

<atom>

Attributes:

<LDAplusu>

Attributes:

<groundstate>

Attributes:

<spin>

Attributes:

<HartreeFock>

Attributes:

<solver>

Attributes:

<OEP>

Attributes:

<RDMFT>

Attributes:

<structureoptimization>

Attributes:

<properties>

<bandstructure>

Attributes:

<plot1d>

<STM>

<plot2d>

<wfplot>

<kstlist>

<plot1d>

<plot2d>

<plot3d>

<dos>

Attributes:

<LSJ>

<kstlist>

<masstensor>

Attributes:

<chargedensityplot>

<plot1d>

<plot2d>

<plot3d>

<exccplot>

<plot1d>

<plot2d>

<plot3d>

<elfplot>

<plot1d>

<plot2d>

<plot3d>

<mvecfield>

<plot2d>

<plot3d>

<xcmvecfield>

<plot2d>

<plot3d>

<electricfield>

<plot2d>

<plot3d>

<gradmvecfield>

<plot1d>

<plot2d>

<plot3d>

<fermisurfaceplot>

Attributes: