Groundstate

Element: groundstate

The groundstate element is required for any calculation. Its attributes are parameters and methods which are used to calculate the ground-state density.

contains: DFTD2parameters (optional)
TSvdWparameters (optional)
spin (optional)
dfthalf (optional)
Hybrid (optional)
solver (optional)
OEP (optional)
output (optional)
libxc (optional)
XPath: /input/groundstate

This element allows for specification of the following attributes: CoreRelativity, ExplicitKineticEnergy, PrelimLinSteps, SymmetricKineticEnergy, ValenceRelativity, autokpt, beta0, betadec, betainc, cfdamp, chgexs, deband, dipolecorrection, dipoleposition, dlinengyfermi, do, energyref, epsband, epschg, epsengy, epsforcescf, epsocc, epspot, fermilinengy, findlinentype, fracinr, frozencore, gmaxvr, isgkmax, ldapu, lmaxapw, lmaxinr, lmaxmat, lmaxvr, lorecommendation, lradstep, maxscl, mixer, mixerswitch, modifiedsv, msecStoredSteps, nempty, ngridk, niterconvcheck, nktot, nosource, nosym, nprad, npsden, nwrite, outputlevel, ptnucl, radialgridtype, radkpt, reducek, rgkmax, scfconv, stype, swidth, symmorph, tevecsv, tfibs, tforce, tpartcharges, vdWcorrection, vkloff, xctype

Attribute: CoreRelativity

Chooses between relativistic/non-relativistic descriptions for core electrons. Pick either "dirac" or "none".

Type: choose from:
dirac
none
Default: "dirac"
Use: optional
XPath: /input/groundstate/@CoreRelativity


Attribute: ExplicitKineticEnergy

If true, the kinetic energy expectation values are calculated explicitly and, then, they are used for calculating the total energy.

Type: boolean
Default: "true"
Use: optional
XPath: /input/groundstate/@ExplicitKineticEnergy


Attribute: PrelimLinSteps

After which SCF iteration is msec mixing supposed to be turned on. Until then linear mixing is applied. Used in msec mixing as choosen with mixer.

Type: integer
Default: "2"
Use: optional
XPath: /input/groundstate/@PrelimLinSteps


Attribute: SymmetricKineticEnergy

If "true", the kinetic-energy matrix elements of muffin-tin functions are calculated by applying gradient to both bra and ket. Otherwise, the whole kinetic-energy operator is applied to ket only, and the surface-term correction is applied to make the hamiltonian hermitian.

Type: boolean
Default: "true"
Use: optional
XPath: /input/groundstate/@SymmetricKineticEnergy


Attribute: ValenceRelativity

Relativistic Hamiltonian to use in groundstate calculations.

  • none - solves non-relativistic Schoedinger equation (SE)
  • zora - solves scalar-relativistic SE within zero-order regular approximation (ZORA)
  • iora* - solves scalar-relativistic SE within infinite-order regular approximation (IORA), the small component is neglected
  • iora - solves scalar-relativistic SE within infinite-order regular approximation (IORA), the small component is included
  • kh* - solves scalar-relativistic SE for the large component, the small component is neglected
  • kh - solves scalar-relativistic SE for the large component, the small component is included

iora, kh* and kh are implemented only for atoms.

Type: choose from:
zora
iora*
iora
kh*
kh
none
Default: "zora"
Use: optional
XPath: /input/groundstate/@ValenceRelativity


Attribute: autokpt

If "true", the set of k-points is determined automatically according to radkpt.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@autokpt


Attribute: beta0

Initial value for mixing parameter. Used in linear mixing as choosen with mixer.

Type: fortrandouble
Default: "0.4d0"
Use: optional
XPath: /input/groundstate/@beta0


Attribute: betadec

Mixing parameter decrease. Used in linear mixing.

Type: fortrandouble
Default: "0.6d0"
Use: optional
XPath: /input/groundstate/@betadec


Attribute: betainc

Mixing parameter increase. Used in linear mixing.

Type: fortrandouble
Default: "1.1d0"
Use: optional
XPath: /input/groundstate/@betainc


Attribute: cfdamp

Damping coefficient for characteristic function.

Type: fortrandouble
Default: "0.0d0"
Use: optional
XPath: /input/groundstate/@cfdamp


Attribute: chgexs

This controls the amount of charge in the unit cell beyond that required to maintain neutrality. It can be set positive or negative depending on whether electron or hole doping is required.

Type: fortrandouble
Default: "0.0d0"
Use: optional
XPath: /input/groundstate/@chgexs


Attribute: 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 wave-function 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 wave-function 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: "0.0025d0"
Use: optional
Unit: Hartree
XPath: /input/groundstate/@deband


Attribute: dipolecorrection

If "true", the dipole correction is applied for slabs oriented along the $z$-direction.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@dipolecorrection


Attribute: dipoleposition

The value of this attribute indicates the position of the jump in electrostatic potential, after the compensating potential (i.e., the dipole correction) is applied. The position is given as a fractional coordinate in the vertical direction. Please note that this jump position should be located within the vacuum region enough far away from the atomic layers, otherwise the compensating potential cannot be correctly applied. It is recommended to put the jump position at the middle of the vacuum layer.

Type: fortrandouble
Default: "1.0d0"
Use: optional
XPath: /input/groundstate/@dipoleposition


Attribute: dlinengyfermi

Energy difference between linearisation and Fermi energy.

Type: fortrandouble
Default: "-0.1d0"
Use: optional
Unit: Hartree
XPath: /input/groundstate/@dlinengyfermi


Attribute: do

Decides if the ground state is calculated starting from scratch, using the densities from file, or if its calculation is skipped and only the associated input parameters are read in.

Type: choose from:
fromscratch
fromfile
skip
Default: "fromscratch"
Use: optional
XPath: /input/groundstate/@do


Attribute: energyref

Energy reference $\varepsilon_\textrm{ref}$ for the scalar-relativistic ZORA. It enters the kinetic energy expression $T=\mathbf{p}\frac{c^2}{2c^2+\varepsilon-v(\mathbf{r})}\mathbf{p}$.

Type: fortrandouble
Default: "0.0d0"
Use: optional
XPath: /input/groundstate/@energyref


Attribute: epsband

Energy tolerance for search of linearisation energies.

Type: fortrandouble
Default: "1.0d-6"
Use: optional
Unit: Hartree
XPath: /input/groundstate/@epsband


Attribute: epschg

Convergence criterion for the maximum allowed error in the calculated total charge beyond which a warning message will be issued.

Type: fortrandouble
Default: "1.0d-5"
Use: optional
XPath: /input/groundstate/@epschg


Attribute: epsengy

Energy convergence tolerance.

Type: fortrandouble
Default: "1.0d-6"
Use: optional
Unit: Hartree
XPath: /input/groundstate/@epsengy


Attribute: epsforcescf

Convergence tolerance for forces (not including IBS contribution) during the SCF run.

Type: fortrandouble
Default: "5.0d-5"
Use: optional
XPath: /input/groundstate/@epsforcescf


Attribute: epsocc

smallest occupancy for which a state will contribute to the density.

Type: fortrandouble
Default: "1.0d-8"
Use: optional
XPath: /input/groundstate/@epsocc


Attribute: 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 optimization runs this results in the forces being calculated, the atomic positions updated and the loop restarted. See also maxscl.

Type: fortrandouble
Default: "1.0d-6"
Use: optional
XPath: /input/groundstate/@epspot


Attribute: fermilinengy

If "true" the linearization energies marked as non-varying are set to the Fermi level plus dlinengyfermi.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@fermilinengy


Attribute: findlinentype

Select method to determine the linearisation energies.

Type: choose from:
Wigner_Seitz
lcharge
logderiv
no_search
Default: "Wigner_Seitz"
Use: optional
XPath: /input/groundstate/@findlinentype


Attribute: fracinr

Fraction of the muffin-tin radius up to which lmaxinr is used as the angular momentum cut-off.

Type: fortrandouble
Default: "0.02d0"
Use: optional
XPath: /input/groundstate/@fracinr


Attribute: frozencore

When set to "true" the frozen core approximation is applied, i.e., the core states are fixed to the atomic states.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@frozencore


Attribute: gmaxvr

Maximum length of |G| for expanding the interstitial density and potential.

Type: fortrandouble
Default: "12.0d0"
Use: optional
XPath: /input/groundstate/@gmaxvr


Attribute: isgkmax

Species for which the muffin-tin radius will be used for calculating gkmax.

Type: integer
Default: "-1"
Use: optional
XPath: /input/groundstate/@isgkmax


Attribute: ldapu

Type of LDA+U method to be used.

Type: choose from:
none
FullyLocalisedLimit
AroundMeanField
FFL-AMF-interpolation
Default: "none"
Use: optional
XPath: /input/groundstate/@ldapu


Attribute: lmaxapw

Angular momentum cut-off for the APW functions.

Type: integer
Default: "8"
Use: optional
XPath: /input/groundstate/@lmaxapw


Attribute: 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: integer
Default: "2"
Use: optional
XPath: /input/groundstate/@lmaxinr


Attribute: lmaxmat

Angular momentum cut-off for the outer-most loop in the hamiltonian and overlap matrix setup.

Type: integer
Default: "8"
Use: optional
XPath: /input/groundstate/@lmaxmat


Attribute: lmaxvr

Angular momentum cut-off for the muffin-tin density and potential.

Type: integer
Default: "8"
Use: optional
XPath: /input/groundstate/@lmaxvr


Attribute: lorecommendation

Local orbitals may be used for improving unoccupied states. But what energy parameters to use? Set this parameter to true, and you will get a list of energies at which the radial wavefunction turns to zero on the muffin-tin sphere. These energies are calculated using atomic potential, and to make them transferable to a general system, use the average of two consecutive atomic energies.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@lorecommendation


Attribute: 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: integer
Default: "1"
Use: optional
XPath: /input/groundstate/@lradstep


Attribute: maxscl

Upper limit for the self-consistency loop.

Type: integer
Default: "200"
Use: optional
XPath: /input/groundstate/@maxscl


Attribute: mixer

Select the mixing (relaxation) scheme for the SCF loop. One has the following options:

Linear mixer ("lin"):

Given the input $\mu^i$ and output $\nu^i$ vectors of the $i$th iteration, the next input vector to the ($i+1$)th iteration is generated using an adaptive mixing scheme. The $j$th component of the output vector is mixed with a fraction of the same component of the input vector:

(1)
\begin{align} \mu^{i+1}_j=\beta^i_j\nu^i_j+(1-\beta^i_j)\mu^i_j, \end{align}

where $\beta^i_j$ is set to $\beta_0$ at initialisation and increased by scaling with $\beta_{\rm inc}$ ($>1$) if $f^i_j\equiv\nu^i_j-\mu^i_j$ does not change sign between loops. If $f^i_j$ does change sign, then $\beta^i_j$ is scaled by $\beta_{\rm dec}$ ($>1$).

Multisecant Broyden potential mixing ("msec")

Pulay mixing ("pulay"):

Pulay's mixing scheme which uses direct inversion in the iterative subspace (DIIS). See Chem. Phys. Lett. 73, 393 (1980).

Type: choose from:
lin
msec
pulay
Default: "msec"
Use: optional
XPath: /input/groundstate/@mixer


Attribute: mixerswitch

Switch between potential (1) and density (2) mixing.

Type: integer
Default: "1"
Use: optional
XPath: /input/groundstate/@mixerswitch


Attribute: modifiedsv

If "true", the construction of the second-variational hamiltonian involves wavefunctions in the basis representation and wavefunctions are not evaluated explicitly. Otherwise, the usual second-variational procedure is used. The first of the two approaches is generally recommended, but it is not implemented for non-collinear and LDA+U calculations.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@modifiedsv


Attribute: msecStoredSteps

How many potentials from previous steps to store. Used in msec mixing as choosen with mixer.

Type: integer
Default: "8"
Use: optional
XPath: /input/groundstate/@msecStoredSteps


Attribute: 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 k-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: integer
Default: "5"
Use: optional
XPath: /input/groundstate/@nempty


Attribute: ngridk

Number of k grid points along the basis vector directions. Alternatively give autokpt and radkpt, or nktot. In the latter cases any value given for ngridk is not used. Notes: Phonon calculations using supercells adjust the k-grid according to the supercell size; if the element xs is given, the present attribute is overwritten by the value in xs for xs-related groundstate calculations; the values of the present attribute are also relevant for calculations related to the element gw.

Type: integertriple
Default: "1 1 1"
Use: optional
XPath: /input/groundstate/@ngridk


Attribute: niterconvcheck

Number of self-consistency iterations over which to test convergence. For example, if niterconvcheck=2, then both the second and third to last iterations are compared to the last one to check convergence. The convergence criteria used are those set up by scfconv.

Type: integer
Default: "2"
Use: optional
XPath: /input/groundstate/@niterconvcheck


Attribute: nktot

Used for the automatic determination of the ${\mathbf k}$-point mesh from the total number of k-points. If nktot is set, then the mesh will be determined in such a way that the number of k-points is proportional to the length of the reciprocal lattice vector in each direction and that the total number of k-points is less than or equal to nktot.

Type: integer
Default: "0"
Use: optional
XPath: /input/groundstate/@nktot


Attribute: nosource

When set to "true", source fields are projected out of the exchange-correlation magnetic field. experimental feature.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@nosource


Attribute: nosym

When set to "true" no symmetries, apart from the identity, are used anywhere in the code.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@nosym


Attribute: nprad

(Obsolete) Order of predictor-corrector polynomial.

Type: integer
Default: "4"
Use: optional
XPath: /input/groundstate/@nprad


Attribute: npsden

Order of polynomial for pseudo-charge density.

Type: integer
Default: "9"
Use: optional
XPath: /input/groundstate/@npsden


Attribute: nwrite

Normally, the density and potentials are written to the file STATE.OUT only after completion of the self-consistent loop. By setting nwrite to a positive integer the file will be written during the loop every nwrite iterations.

Type: integer
Default: "0"
Use: optional
XPath: /input/groundstate/@nwrite


Attribute: outputlevel

Specify amount of information which is printed to files:

  • none - no output is produced
  • low - minimal output is produced
  • normal - (default) standard information
  • high - detailed output
Type: choose from:
none
low
normal
high
Default: "normal"
Use: optional
XPath: /input/groundstate/@outputlevel


Attribute: ptnucl

The attrubute ptnucl is "true" if the nuclei are to be treated as point charges, if "false" the nuclei have a finite spherical distribution.

Type: boolean
Default: "true"
Use: optional
XPath: /input/groundstate/@ptnucl


Attribute: radialgridtype

The parameter defines a functional form how radial-grid points are distributed. Choose from "cubic", "exponential" and "expocubic". "cubic" is the most suitable one for a majority of calculations, but switch to "expocubic" if you set the innermost grid point very close to a nucleus.

Type: string
Default: "cubic"
Use: optional
XPath: /input/groundstate/@radialgridtype


Attribute: radkpt

Used for the automatic determination of the k-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: "40.0d0"
Use: optional
XPath: /input/groundstate/@radkpt


Attribute: reducek

If the attribute reducek is "true" the $\bf{k}$-point set is reduced with the crystal symmetries.

Type: boolean
Default: "true"
Use: optional
XPath: /input/groundstate/@reducek


Attribute: rgkmax

The parameter rgkmax implicitly determines the number of basis functions and is one of the crucial parameters for the accuracy of the calculation. It represents the product of two quantities: $R_{MT,\, Min}$, the smallest of all muffin-tin radii, and $|{ \bf G}+{ \bf k}|_{max}$, the maximum length for the ${ \bf G}+{ \bf k}$ vectors. Because each ${ \bf G}+{ \bf k}$ vector represents one basis function, rgkmax gives the number of basis functions used for solving the Kohn-Sham equations. Typical values of rgkmax are between 6 and 9. However, for systems with very short bond-lengths, significantly smaller values may be sufficient. This may especially be the case for materials containing carbon, where rgkmax may be 4.5-5, or hydrogen, where even values between 3 and 4 may be sufficient. In any case, a convergence check is indispensible for a proper choice of this parameter for your system!

Type: fortrandouble
Default: "7.0d0"
Use: optional
XPath: /input/groundstate/@rgkmax


Attribute: scfconv

Specify the SCF convergence criteria

  • "energy" - only the total energy of the system is used as a convergence criterion. If the calculation of the atomic forces is required (e.g., in the optimization of the atomic positions) the non-IBS contribution to the atomic forces is added as a further convergence criterion.
  • "potential" - only the Kohn-Sham potential is used as a convergence criterion. If atomic forces are required the convergence criterion is extended to include non-IBS forces.
  • "multiple" - total energy, Kohn-Sham potential, and total electronic charge of the system are used as convergence criteria. If atomic forces are required the convergence criterion is extended to include non-IBS forces.
Type: string
Default: "multiple"
Use: optional
XPath: /input/groundstate/@scfconv


Attribute: stype

A smooth approximation to the Dirac delta function is needed to compute the occupancies of the Kohn-Sham states. The attribute swidth determines the width of the approximate delta function.

Type: choose from:
Gaussian
Methfessel-Paxton 1
Methfessel-Paxton 2
Fermi Dirac
Square-wave impulse
libbzint
Default: "Gaussian"
Use: optional
XPath: /input/groundstate/@stype


Attribute: swidth

Width of the smooth approximation to the Dirac delta function (must be greater than zero).

Type: fortrandouble
Default: "0.001d0"
Use: optional
Unit: Hartree
XPath: /input/groundstate/@swidth


Attribute: symmorph

When set to "true" only symmorphic space-group operations are to be considered, i.e. only symmetries without non-primitive translations are used anywhere in the code.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@symmorph


Attribute: tevecsv

The attribute tevecsv is "true" if second-variational eigenvectors are calculated.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@tevecsv


Attribute: tfibs

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.

Type: boolean
Default: "true"
Use: optional
XPath: /input/groundstate/@tfibs


Attribute: tforce

Decides if the force should be calculated at the end of the self-consistent cycle.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@tforce


Attribute: tpartcharges

The attribute tpartcharges is "true" if partial charges for each state j, atom alpha and for each lm combination are calculated.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/@tpartcharges


Attribute: vdWcorrection

Adds dispersion (van-der-Waals) correction to total energy after the last SCF iteration. If forces are calculated, an appropriate dispersion correction is applied. Available methods are

  • "DFTD2": This is the DFT-D2 method by Stefan Grimme which is introduced in Semiempirical GGA-type density functional constructed with a long-range dispersion correction, J. Comput. Chem. 27, 1787-1799 (2006).
  • "TSvdW": This is the TS-vdW method by Alexandre Tkatchenko and Matthias Scheffler introduced in Accurate molecular van-der-Waals interactions from ground-state electron density and free-atom reference data, Phys. Rev. Lett. 102, 073005 (2009).

Parameters corresponding to each method can be specified using the subelements DFTD2parameters and TSvdWparameters inside the element groundstate. It is also possible to decouple these van-der-Waals corrections from a complete ground-state calculation. In this case, you can use the subelements DFTD2 and TSvdW inside the element properties.

Type: choose from:
none
DFTD2
TSvdW
Default: "none"
Use: optional
XPath: /input/groundstate/@vdWcorrection


Attribute: vkloff

The ${\mathbf k}$-point offset vector in lattice coordinates.

Type: vect3d
Default: "0.0d0 0.0d0 0.0d0"
Use: optional
XPath: /input/groundstate/@vkloff


Attribute: xctype

Type of exchange-correlation functional to be used

  • No exchange-correlation funtional ( $E_{\rm xc}\equiv 0$ )
  • LDA, Perdew-Zunger/Ceperley-Alder, Phys. Rev. B 23, 5048 (1981)
  • LSDA, Perdew-Wang/Ceperley-Alder, Phys. Rev. B 45, 13244 (1992)
  • LDA, X-alpha approximation, J. C. Slater, Phys. Rev. 81, 385 (1951)
  • LSDA, von Barth-Hedin, J. Phys. C 5, 1629 (1972)
  • GGA, Perdew-Burke-Ernzerhof (PBE), Phys. Rev. Lett. 77, 3865 (1996)
  • GGA, Revised PBE, Zhang-Yang, Phys. Rev. Lett. 80, 890 (1998)
  • GGA, PBEsol, arXiv:0707.2088v1 (2007)
  • GGA, asymptotically corrected PBE (acPBE), arXiv:1409.4834 (2014)
  • GGA, Wu-Cohen exchange (WC06) with PBE correlation, Phys. Rev. B 73, 235116 (2006)
  • GGA, Armiento-Mattsson (AM05) spin-unpolarised functional, Phys. Rev. B 72, 085108 (2005)
  • EXX, Exact Exchange, Phys. Rev. Lett. 95, 136402 (2005)
  • Hybrid, PBE0, J. Chem. Phys. 110, 5029 (1999)
Type: choose from:
LDA_PZ
LDA_PW
LDA_XALPHA
LDA_vBH
GGA_PBE
GGA_PBE_R
GGA_PBE_SOL
GGA_WC
GGA_AM05
GGA_AC_PBE
HYB_PBE0
HYB_LDA0
EXX
none
Default: "GGA_PBE"
Use: optional
XPath: /input/groundstate/@xctype

Element: DFTD2parameters

This element allows to customize parameters when either the option "DFTD2" of the attribute vdWcorrection is chosen, or the subelement DFTD2 of the element properties is specified.

Type: no content
XPath: /input/groundstate/DFTD2parameters

This element allows for specification of the following attributes: cutoff, d, s6, sr6

Attribute: cutoff

Cutoff distance of interatomic interactions for the method "DFTD2". In the sum over all pairwise interactions, only pairs of atoms are considered which are closer to each other than the value of the cutoff attribute.

Type: fortrandouble
Default: "95.0d0"
Use: optional
XPath: /input/groundstate/DFTD2parameters/@cutoff


Attribute: d

This damping constant determines the steepnes of the damping function for the method "DFTD2".

Type: fortrandouble
Default: "20.0d0"
Use: optional
XPath: /input/groundstate/DFTD2parameters/@d


Attribute: s6

Global scaling factor for all $C_6$-dispersion coefficients for the method "DFTD2". This factor depends on the exchange-correlation functional in use. The default value suits PBE calculations.

Type: fortrandouble
Default: "0.75d0"
Use: optional
XPath: /input/groundstate/DFTD2parameters/@s6


Attribute: sr6

Scaling factor for van-der-Waals radii for the method "DFTD2". This factor depends on the exchange-correlation functional in use. The default value suits PBE calculations.

Type: fortrandouble
Default: "1.1d0"
Use: optional
XPath: /input/groundstate/DFTD2parameters/@sr6

Element: TSvdWparameters

This element allows to customize parameters when either the option "TSvdW" of the attribute vdWcorrection is chosen, or the subelement TSvdW of the element properties is specified.

Type: no content
XPath: /input/groundstate/TSvdWparameters

This element allows for specification of the following attributes: cutoff, d, nr, nsph, s6, sr6

Attribute: cutoff

Cutoff distance of interatomic interactions for the method "TSvdW". In the sum over all pairwise interactions, only pairs of atoms are considered which are closer to each other than the value of the cutoff attribute.

Type: fortrandouble
Default: "95.0d0"
Use: optional
XPath: /input/groundstate/TSvdWparameters/@cutoff


Attribute: d

This damping constant determines the steepnes of the damping function for the method "TSvdW".

Type: fortrandouble
Default: "20.0d0"
Use: optional
XPath: /input/groundstate/TSvdWparameters/@d


Attribute: nr

Number of radial grid points for the Gauss-Chebyshev quadrature.

Type: integer
Default: "120"
Use: optional
XPath: /input/groundstate/TSvdWparameters/@nr


Attribute: nsph

Number of Lebedev grid points. The only possible values are: "1", "6", "14", "26", "38", "50", "74", "86", "110", "146", "170", "194", "230", "266", "302", "350", "434", "590", "770", "974", "1202", "1454", "1730", "2030", "2354", "2702", "3074", "3740", "3890", "4334", "4802", "5294", "5810".

Type: integer
Default: "590"
Use: optional
XPath: /input/groundstate/TSvdWparameters/@nsph


Attribute: s6

Global scaling factor for all $C_6$-dispersion coefficients for the method "TSvdW".

Type: fortrandouble
Default: "1.0d0"
Use: optional
XPath: /input/groundstate/TSvdWparameters/@s6


Attribute: sr6

Scaling factor for van-der-Waals radii for the method "TSvdW". This factor depends on the exchange-correlation functional in use. The default value suits PBE calculations.

Type: fortrandouble
Default: "0.94d0"
Use: optional
XPath: /input/groundstate/TSvdWparameters/@sr6

Element: spin

If the spin element is present, calculation is done with spin polarization.

Type: no content
XPath: /input/groundstate/spin

This element allows for specification of the following attributes: bfieldc, fixspin, momfix, reducebf, spinorb, spinsprl, taufsm, vqlss

Attribute: bfieldc

Allows to apply a constant ${ \bf B}_{\tt ext}$ field. This is an external constant magnetic field applied throughout the entire unit cell and enters the second-variational Hamiltonian as

(2)
\begin{align} \frac{g_e\,\alpha}{4}\;\vec{\sigma}\cdot{\bf B}_{\tt ext}\,, \end{align}

where $g_e$ is the electron $g$-factor ($g_e$=2.0023193043718). The external magnetic 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 (when the attribute outputlevel is set to"high") should be added to the total energy by hand. This external magnetic field is applied hroughout the entire unit cell. To apply magnetic fields in particular muffin-tins use the bfcmt vectors in the atom elements. Collinear calculations are more efficient if the field is applied in the $z$-direction.

Type: vect3d
Default: "0.0d0 0.0d0 0.0d0 "
Use: optional
XPath: /input/groundstate/spin/@bfieldc


Attribute: fixspin

Type: choose from:
none
total FSM
localmt FSM
both
Default: "none"
Use: optional
XPath: /input/groundstate/spin/@fixspin


Attribute: momfix

The desired total moment for a fixed spin moment (FSM) calculation.

Type: vect3d
Default: "0.0d0 0.0d0 0.0d0"
Use: optional
XPath: /input/groundstate/spin/@momfix


Attribute: reducebf

After each iteration the external magnetic fields are multiplied with reducebf. This allows 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 atom element.

Type: fortrandouble
Default: "1.0d0"
Use: optional
XPath: /input/groundstate/spin/@reducebf


Attribute: spinorb

If spinorb is "true", then a $\boldsymbol \sigma\cdot{ \bf L}$ term is added to the second-variational Hamiltonian.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/spin/@spinorb


Attribute: spinsprl

Set to "true" if a spin-spiral calculation is required. Experimental feature for the calculation of spin-spiral states. See vqlss for details.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/spin/@spinsprl


Attribute: taufsm

The effective magnetic field required for fixing the spin moment to a given value, is updated according to

(3)
\begin{align} {\bf B}_{\tt FSM}^{i+1}={\bf B}_{\tt FSM}^i+\tau_{\tt FSM}\left( \boldsymbol{\mu}^i-\boldsymbol{\mu}_{\tt FSM}\right)\,, \end{align}

for iteration $i$. It must be positive.

Type: fortrandouble
Default: "0.01d0"
Use: optional
XPath: /input/groundstate/spin/@taufsm


Attribute: vqlss

This attribute allows to specify the ${ \bf q}$-vector of the spin-spiral state in lattice coordinates. Spin-spirals arise from spinor states assumed to be of the form

(4)
\begin{align} \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}} \\ \phantom{o} \\ U^{{ \bf q}\downarrow}_{ \bf k}({ \bf r})\;e^{i({ \bf k-q/2})\cdot{ \bf r}} \\ \end{array} \right)\,. \end{align}

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

(5)
\begin{align} {\bf m}^{ \bf q}({ \bf r})=\left[m_x({\bf r})\,\cos({ \bf q \cdot r}),\; m_y({\bf r})\,\sin({ \bf q \cdot r}),\; m_z({\bf r})\right]\,, \end{align}

where $m_x$, $m_y$, and $m_z$ have the periodicity of the lattice. See also spinsprl.

Type: vect3d
Default: "0.0d0 0.0d0 0.0d0"
Use: optional
XPath: /input/groundstate/spin/@vqlss

Element: dfthalf

The presence of this element triggers DFT-1/2 calculations.

Type: no content
XPath: /input/groundstate/dfthalf

This element allows for specification of the following attributes: printVSfile

Attribute: printVSfile

When set to "true", the self-energy correction potential $V_S({\bf r})$ (as defined in the DFT-1/2 method) is calculated for each constituent atomic species and written into the files VS_S*.OUT, where * ranges from 1 to the number of atomic species. The exciting run quits after the printing. In this case, a serial calculation is suggested. It is useful to visualize the self-energy potential, or for debugging purposes.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/dfthalf/@printVSfile

Element: Hybrid

Options for hybrid functionals.

Type: no content
XPath: /input/groundstate/Hybrid

This element allows for specification of the following attributes: exchangetype, excoeff, maxscl

Attribute: exchangetype

Type of exchange (Hartree Fock or OEP) to be used for the exact exchange.

Type: choose from:
HF
OEP
Default: "HF"
Use: optional
XPath: /input/groundstate/Hybrid/@exchangetype


Attribute: excoeff

Define value of the mixing parameter for exact exchange. ATTENTION: If you are using libxc, the libxc settings will be employed and your choice of this parameter will be ignored.

Type: fortrandouble
Default: "0.25d0"
Use: optional
XPath: /input/groundstate/Hybrid/@excoeff


Attribute: maxscl

Upper limit for the Hybrids self-consistency loop.

Type: integer
Default: "50"
Use: optional
XPath: /input/groundstate/Hybrid/@maxscl

Element: solver

Optional configuration options for eigenvector solver.

Type: no content
XPath: /input/groundstate/solver

This element allows for specification of the following attributes: ArpackImproveInverse, ArpackLinSolve, ArpackShift, ArpackUserDefinedShift, DecompPrec, epsarpack, evaltol, packedmatrixstorage, type

Attribute: ArpackImproveInverse

Tells whether iterative improvement should be applied during the shift-and-invert procedure. Setting to true may be useful, for instance, when DecompPrec is set to "sp".

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/solver/@ArpackImproveInverse


Attribute: ArpackLinSolve

Linear solve method during shift-and-invert process in ARPACK. Pick either LDL, LU, LL, Diag and InvertOnce.

Type: choose from:
LDL
LL
LU
Diag
InvertOnce
Default: "LDL"
Use: optional
XPath: /input/groundstate/solver/@ArpackLinSolve


Attribute: ArpackShift

Energy shift in the shift-and-invert procedure in the ARPACK solver.

Type: fortrandouble
Default: "-1.0d0"
Use: optional
Unit: Hartree
XPath: /input/groundstate/solver/@ArpackShift


Attribute: ArpackUserDefinedShift

ArpackShift will be used if this flag is set to true, otherwise the energy shift will be determined internally.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/solver/@ArpackUserDefinedShift


Attribute: DecompPrec

Precision used during the factorization in ARPACK. Pick either sp or dp.

Type: choose from:
sp
dp
Default: "dp"
Use: optional
XPath: /input/groundstate/solver/@DecompPrec


Attribute: epsarpack

Tolerance parameter for the ARPACK shift invert solver

Type: fortrandouble
Default: "1.0d-14"
Use: optional
XPath: /input/groundstate/solver/@epsarpack


Attribute: evaltol

Error tolerance for the first-variational eigenvalues using the LAPACK Solver

Type: fortrandouble
Default: "1.0d-14"
Use: optional
Unit: Hartree
XPath: /input/groundstate/solver/@evaltol


Attribute: packedmatrixstorage

In the default calculation the matrix is sored in packed form. When using multi-threaded BLAS setting this parameter to "false" increases efficiency.

Type: boolean
Default: "false"
Use: optional
XPath: /input/groundstate/solver/@packedmatrixstorage


Attribute: type

Selects the eigenvalue solver for the first variational equation

Type: choose from:
Lapack
Arpack
Default: "Lapack"
Use: optional
XPath: /input/groundstate/solver/@type

Element: OEP

Necessary, if exact exchange calculation is to be performed.

Type: no content
XPath: /input/groundstate/OEP

This element allows for specification of the following attributes: convoep, maxitoep, tauoep

Attribute: convoep

Convergence tolerance for OEP residue when solving the exact exchange integral equations.

Type: fortrandouble
Default: "1e-11"
Use: optional
XPath: /input/groundstate/OEP/@convoep


Attribute: maxitoep

Maximum number of iterations when solving the exact exchange integral equations.

Type: integer
Default: "300"
Use: optional
XPath: /input/groundstate/OEP/@maxitoep


Attribute: tauoep

The optimised effective potential is determined using an iterative method. Phys. Rev. Lett. 98, 196405 (2007). At the first iteration the step length is set to tauoep(1). During 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: "1.0d0 0.2d0 1.5d0"
Use: optional
XPath: /input/groundstate/OEP/@tauoep

Element: output

Specifications on the file formats for output files.

Type: no content
XPath: /input/groundstate/output

This element allows for specification of the following attributes: state

Attribute: state

Selects the file format of the STATE file.

Type: choose from:
binary
XML
Default: "binary"
Use: optional
XPath: /input/groundstate/output/@state

Element: libxc

Type: no content
XPath: /input/groundstate/libxc

This element allows for specification of the following attributes: correlation, exchange, xc

Attribute: correlation

Type: choose from:
none
XC_LDA_C_WIGNER
XC_LDA_C_RPA
XC_LDA_C_HL
XC_LDA_C_GL
XC_LDA_C_XALPHA
XC_LDA_C_VWN
XC_LDA_C_VWN_RPA
XC_LDA_C_PZ
XC_LDA_C_PZ_MOD
XC_LDA_C_OB_PZ
XC_LDA_C_PW
XC_LDA_C_PW_MOD
XC_LDA_C_OB_PW
XC_LDA_C_2D_AMGB
XC_LDA_C_2D_PRM
XC_LDA_C_vBH
XC_LDA_C_1D_CSC
XC_LDA_C_ML1
XC_LDA_C_ML2
XC_LDA_C_GOMBAS
XC_LDA_C_PW_RPA
XC_LDA_C_1D_LOOS
XC_LDA_C_RC04
XC_LDA_C_VWN_1
XC_LDA_C_VWN_2
XC_LDA_C_VWN_3
XC_LDA_C_VWN_4
XC_GGA_C_OP_XALPHA
XC_GGA_C_OP_G96
XC_GGA_C_OP_PBE
XC_GGA_C_OP_B88
XC_GGA_C_FT97
XC_GGA_C_SPBE
XC_GGA_C_REVTCA
XC_GGA_C_TCA
XC_GGA_C_PBE
XC_GGA_C_LYP
XC_GGA_C_P86
XC_GGA_C_PBE_SOL
XC_GGA_C_PW91
XC_GGA_C_AM05
XC_GGA_C_XPBE
XC_GGA_C_LM
XC_GGA_C_PBE_JRGX
XC_GGA_C_RGE2
XC_GGA_C_WL
XC_GGA_C_WI
XC_GGA_C_SOGGA11
XC_GGA_C_WI0
XC_GGA_C_SOGGA11_X
XC_GGA_C_APBE
XC_GGA_C_OPTC
Default: "XC_GGA_C_PBE"
Use: optional
XPath: /input/groundstate/libxc/@correlation


Attribute: exchange

Type: choose from:
none
XC_LDA_X
XC_LDA_X_2D
XC_LDA_X_1D
XC_GGA_X_SSB_SW
XC_GGA_X_SSB
XC_GGA_X_SSB_D
XC_GGA_X_BPCCAC
XC_GGA_X_PBE
XC_GGA_X_PBE_R
XC_GGA_X_B86
XC_GGA_X_HERMAN
XC_GGA_X_B86_MGC
XC_GGA_X_B88
XC_GGA_X_G96
XC_GGA_X_PW86
XC_GGA_X_PW91
XC_GGA_X_OPTX
XC_GGA_X_DK87_R1
XC_GGA_X_DK87_R2
XC_GGA_X_LG93
XC_GGA_X_FT97_A
XC_GGA_X_FT97_B
XC_GGA_X_PBE_SOL
XC_GGA_X_RPBE
XC_GGA_X_WC
XC_GGA_X_MPW91
XC_GGA_X_AM05
XC_GGA_X_PBEA
XC_GGA_X_MPBE
XC_GGA_X_XPBE
XC_GGA_X_2D_B86_MGC
XC_GGA_X_BAYESIAN
XC_GGA_X_PBE_JSJR
XC_GGA_X_2D_B88
XC_GGA_X_2D_B86
XC_GGA_X_2D_PBE
XC_GGA_X_OPTB88_VDW
XC_GGA_X_PBEK1_VDW
XC_GGA_X_OPTPBE_VDW
XC_GGA_X_RGE2
XC_GGA_X_RPW86
XC_GGA_X_KT1
XC_GGA_X_MB88
XC_GGA_X_SOGGA
XC_GGA_X_SOGGA11
XC_GGA_X_C09X
XC_GGA_X_LB
XC_GGA_X_LBM
XC_GGA_X_OL2
XC_GGA_X_APBE
XC_GGA_X_HTBS
XC_GGA_X_AIRY
XC_GGA_X_LAG
Default: "XC_GGA_X_PBE"
Use: optional
XPath: /input/groundstate/libxc/@exchange


Attribute: xc

Combined functionals. If set it overrides the exchange and the correlation attributes.

Type: choose from:
none
XC_LDA_XC_TETER93
XC_GGA_XC_HCTH_407P
XC_GGA_XC_HCTH_P76
XC_GGA_XC_HCTH_P14
XC_GGA_XC_B97_GGA1
XC_GGA_XC_HCTH_A
XC_GGA_XC_KT2
XC_GGA_XC_TH1
XC_GGA_XC_TH2
XC_GGA_XC_TH3
XC_GGA_XC_TH4
XC_GGA_XC_HCTH_93
XC_GGA_XC_HCTH_120
XC_GGA_XC_HCTH_147
XC_GGA_XC_HCTH_407
XC_GGA_XC_EDF1
XC_GGA_XC_XLYP
XC_GGA_XC_B97
XC_GGA_XC_B97_1
XC_GGA_XC_B97_2
XC_GGA_XC_B97_D
XC_GGA_XC_B97_K
XC_GGA_XC_B97_3
XC_GGA_XC_PBE1W
XC_GGA_XC_MPWLYP1W
XC_GGA_XC_PBELYP1W
XC_GGA_XC_SB98_1a
XC_GGA_XC_SB98_1b
XC_GGA_XC_SB98_1c
XC_GGA_XC_SB98_2a
XC_GGA_XC_SB98_2b
XC_GGA_XC_SB98_2c
XC_GGA_XC_MOHLYP
XC_GGA_XC_MOHLYP2
XC_GGA_XC_TH_FL
XC_GGA_XC_TH_FC
XC_GGA_XC_TH_FCFO
XC_GGA_XC_TH_FCO
XC_HYB_GGA_XC_B3PW91
XC_HYB_GGA_XC_B3LYP
XC_HYB_GGA_XC_B3P86
XC_HYB_GGA_XC_O3LYP
XC_HYB_GGA_XC_mPW1K
XC_HYB_GGA_XC_PBEH
XC_HYB_GGA_XC_B97
XC_HYB_GGA_XC_B97_1
XC_HYB_GGA_XC_B97_2
XC_HYB_GGA_XC_X3LYP
XC_HYB_GGA_XC_B1WC
XC_HYB_GGA_XC_B97_K
XC_HYB_GGA_XC_B97_3
XC_HYB_GGA_XC_MPW3PW
XC_HYB_GGA_XC_B1LYP
XC_HYB_GGA_XC_B1PW91
XC_HYB_GGA_XC_mPW1PW
XC_HYB_GGA_XC_MPW3LYP
XC_HYB_GGA_XC_SB98_1a
XC_HYB_GGA_XC_SB98_1b
XC_HYB_GGA_XC_SB98_1c
XC_HYB_GGA_XC_SB98_2a
XC_HYB_GGA_XC_SB98_2b
XC_HYB_GGA_XC_SB98_2c
XC_HYB_GGA_XC_BHANDH
XC_HYB_GGA_XC_BHANDHLYP
XC_HYB_GGA_XC_MB3LYP_RC04
Default: "none"
Use: optional
XPath: /input/groundstate/libxc/@xc

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.

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