##master-page:HelpTemplate
##master-date:Unknown-Date
#format wiki
#language en
#Please change following line to BDF module name

= SCF =
<<TableOfContents(4)>>

{{{
HF/DFT.
}}}
== General keywords ==
=== RHF/UHF/ROHF ===
{{{#!wiki
  Must input one of them if Hartree-Fock calculation is required. Required for restricted/unrestricted/restricted open shell Hartree-Fock calculations.
}}}
Example:

{{{
$scf
RHF
$end
}}}
=== RKS/UKS/ROKS ===
{{{#!wiki
  Must input one of them if Kohn-Sham calculation is required. Required for restricted/unrestricted/restricted open shell  Kohn-Sham   calculations.
}}}
=== Occupy ===
{{{#!wiki
  Used in RHF/RKS. Set double occupied number of each irreps.
  The following line is an integer array, <<latex($noccu(i),i=1,\ldots, nirreps$)>>.
}}}
=== Alpha ===
{{{#!wiki
  Used in UHF/ROHF/UKS/ROKS. Set number of alpha orbitals in each irreps.
  The following line is an integer array, <<latex($nalpha(i),i=1,\ldots, nirreps$)>>.
}}}
=== Beta ===
{{{#!wiki
  Used in UHF/ROHF/UKS/ROKS. Set number of beta orbitals in each irreps.
  The following line is an integer array, <<latex($nbeta(i),i=1,\ldots , nirreps$)>>.
}}}
=== Charge ===
{{{#!wiki
 Charge of the state.
}}}
=== Spin ===
{{{#!wiki
  Spin of the state. The value is 2S+1.
}}}
=== Atomorb ===
{{{#!wiki
 Calculate atomic orbitals and save atomic orbitals on file $BDF_WORKDIR/$BDFTASK.atmorb when this keyword is used.
}}}
=== Guess ===
{{{#!wiki
 Method to get initial guess orbital. The following line is a string.
 Values: Atom, Hcore, Huckel, Read.<<BR>>
 If Read is used, the old orbital will be read. The program searches for the following files, in that order:<<BR>>
 (1) $BDF_TMPDIR/[taskname].inporb<<BR>>
 (2) $BDF_TMPDIR/inporb<<BR>>
 (3) $BDF_WORKDIR/[taskname].scforb<<BR>>
 The initial guess orbitals will be read from the first file that exists, and will be Lowdin orthogonalized before they are used in the SCF calculation. If the orbital file is invalid, corrupted, or incompatible with the current calculation (e.g. the number of basis functions is different), then the atomic guess will be used instead.<<BR>>
 Notice that we recommend users choose Hcore for the following MCSCF calculations.
}}}
=== Mixorb ===
{{{#!wiki
 Mix the orbitals of the initial guess wavefunction. This is useful in two contexts: (1) generation of broken-symmetry wavefunctions, and (2) swapping of one or more occupied orbital(s) with virtual orbital(s) in order to converge to a different electronic state. Note that normally Mixorb is only useful when the initial guess is read from a file (see the Guess keyword), otherwise the initial guess orbitals are not known at the time the input file is written, which means that the behavior of Mixorb will be unpredictable.<<BR>>
 The first line after the keyword is an integer, N, that specifies how many orbital pairs need to be mixed. The 2nd to (N+1)th lines each consists of 5 numbers: the spin of the orbital pair (1=alpha, 2=beta), the irreducible representation (irrep) of the orbital pair, the index of the first orbital, the index of the second orbital, and the mixing angle (in degrees).<<BR>>
}}}
 . For example:

{{{
$scf
RHF
guess
read
mixorb
1
1,3,10,11,45
$end
}}}
 . will mix the 10th alpha orbital of the 3rd irrep with the 11th alpha orbital of the 3rd irrep like <<latex($\psi_{10}^{new}=\frac{1}{\sqrt{2}}(\psi_{10}+\psi_{11})$)>> and <<latex($\psi_{11}^{new}=\frac{1}{\sqrt{2}}(\psi_{10}-\psi_{11})$)>>, while

{{{
$scf
UHF
guess
read
mixorb
1
2,5,7,8,90
$end
}}}
 . will simply swap the 7th beta orbital of the 5th irrep with the 8th beta orbital of the 5th irrep, since mixing two orbitals by an angle of 90 degrees is equivalent to swapping them. If orbital 7 was previously an occupied orbital and orbital 8 was a virtual orbital, then after swapping the occupation pattern will be reversed, with orbital 7 vacant and orbital 8 occupied.

== DFT functional keywords ==
=== DFT ===
{{{#!wiki
 DFT functional used in Kohn-Sham calculation. Example:
}}}
{{{
$scf
RKS
DFT
 B3LYP
$end
}}}
Below is a list of functionals supported by the SCF module, together with whether they are supported by other modules, and whether they are supported by the DFT-D3 dispersion correction:

||Functional ||SCF/Elecoup ||TDDFT/NMR ||Resp (excluding gradients & NACMEs) ||Resp (gradients & NACMEs) ||DFT-D3 ||
||||||||||||<style="text-align:center">'''LDA functionals''' ||
||LSDA ||√ ||√ ||√ ||√ ||× ||
||SVWN5 ||√ ||√ ||√ ||√ ||× ||
||SAOP ||√ ||√ ||× ||× ||× ||
||||||||||||<style="text-align:center">'''GGA functionals''' ||
||BP86 ||√ ||√ ||√ ||√ ||√ ||
||BLYP ||√ ||√ ||√ ||√ ||√ ||
||PBE ||√ ||√ ||√ ||√ ||√ ||
||PW91 ||√ ||√ ||× ||× ||× ||
||OLYP ||√ ||√ ||√ ||√ ||× ||
||KT2 ||√ ||√ ||× ||× ||× ||
||||||||||||<style="text-align:center">'''Hybrid GGA functionals''' ||
||B3LYP [a] ||√ ||√ ||√ ||√ ||√ ||
||GB3LYP [b] ||√ ||√ ||√ ||√ ||√ ||
||BHHLYP ||√ ||√ ||√ ||√ ||√ ||
||B3PW91 ||√ ||√ ||× ||× ||√ ||
||PBE0 ||√ ||√ ||√ ||√ ||√ ||
||HFLYP ||√ ||√ ||√ ||√ ||× ||
||VBLYP ||√ ||√ ||× ||× ||× ||
||SF5050 ||√ ||√ ||× ||× ||× ||
||||||||||||<style="text-align:center">'''Range-separated hybrid GGA functionals''' ||
||CAM-B3LYP [c] ||√ ||√ [f] ||√ ||× ||√ ||
||LC-BLYP [c] ||√ ||√ [f] ||√ ||× ||× ||
||wB97 [d] ||√ ||√ [f] ||× ||× ||× ||
||wB97X [e] ||√ ||√ [f] ||× ||× ||× ||
||wB97X-D [e]||√||√ [f] ||× ||× ||√ ||
||||||||||||<style="text-align:center">'''Meta-GGA and hybrid meta-GGA functionals''' ||
||M06L ||√ ||√ [f] ||× ||√ [g] ||× ||
||M062X ||√ ||√ [f] ||× ||√ [g] ||× ||
||M11L ||√ ||√ [f] ||× ||√ [g] ||× ||
||MN12L ||√ ||√ [f] ||× ||√ [g] ||× ||
||MN15L ||√ ||√ [f] ||× ||√ [g] ||× ||
||TPSS ||√ ||√ [f] ||× ||√ [g] ||× ||
||TPSSh ||√ ||√ [f] ||× ||√ [g] ||× ||
||SCAN ||√ ||√ [f] ||× ||√ [g] ||× ||
||r2SCAN ||√ ||√ [f] ||× ||√ [g] ||× ||
||SCAN0 ||√ ||√ [f] ||× ||√ [g] ||× ||
||PW6B95 ||√ ||√ [f] ||× ||√ [g] ||× ||
||||||||||||<style="text-align:center">'''Double hybrid functionals''' ||
||B2PLYP [h] ||√ [i] ||× ||× ||× ||√ ||

[a] The B3LYP functional used in Turbomole, ORCA, etc., where the LDA correlation is VWN5.<<BR>>
[b] The B3LYP functional used in Gaussian, etc., where the LDA correlation is VWN3.<<BR>>
[c] Must specify rs 0.33 in $xuanyuan.<<BR>>
[d] Must specify rs 0.40 in $xuanyuan.<<BR>>
[e] Must specify rs 0.30 in $xuanyuan.<<BR>>
[f] TDDFT only.<<BR>>
[g] Ground-state gradients only.<<BR>>
[h] Must add a $mp2 block after the $scf block to calculate the MP2 contribution to B2PLYP.<<BR>>
[i] Elecoup nominally supported, but the contribution of perturbative doubles is not included, i.e. the elecoup results are approximate.

Alternatively, the user may specify the exchange and correlation functionals separately, for example
{{{
$scf
RKS
DFT
 B88 VWN5
$end
}}}
specifies the functional BVWN5. The supported exchange and correlation functionals are:
{{{
Exchange functionals: LDA, B3, PW91, B88, LC-B88, FT97, PBE
Correlation functionals: VWN, VWN5, PW91, PW92, P86, PBE, FT97, LYP, PZ81
}}}

=== FACEX ===
{{{#!wiki
  Specify the ratio of HF exchange of the functional. This keyword is only supported for the following functionals: LSDA, SVWN5, PBE, PBE0, PW91, BP86, BLYP, B3LYP, GB3LYP, B3PW91, BHHLYP, SF5050 and B2PLYP.
  For example, the following input defines the PBE38 functional (cx=0.375):
}}}
{{{
$scf
...
DFT
 PBE
facex
 0.375
$end
}}}

=== FACCO ===
{{{#!wiki
  Specify the ratio of MP2 correlation of the functional. This keyword is only supported for B2PLYP.
  For example, the following input defines the DSD-BLYP functional (herein the fss and fos keywords are the spin-component-scaling (SCS) parameters. For details, see [[mp2]]):
}}}
{{{
$scf
...
dft
 B2PLYP
facex
 0.75
facco # One minus DFT correlation factor
 0.47
$end

$mp2
fss
 0.60
fos
 0.46
$end
}}}

=== RS ===
{{{#!wiki
  Alpha and beta value in range-separated functional calculation (CAM-B3LYP, LC-BLYP). The following line are two
  float number. For example : 0.33 0.15
}}}
=== D3 ===
{{{#!wiki
  Grimme's dispersion corrrection for DFT.
}}}
== DFT grid keywords ==
=== NPTRAD ===
{{{#!wiki
  Number of radius grid points.
}}}
=== NPTANG ===
{{{#!wiki
 Number of angular grid points.
}}}
=== COSXNGRID ===
{{{#!wiki
Numbers of radius and angular grids of each atomic type in COSX calculation.
Example: CH2 molecule
20 194  #  Grid for C
20 194 #  Grid for H
}}}
=== Grid ===
{{{#!wiki
  Set DFT grid. Supported values are: Ultra Coarse, Coarse, Medium, Fine, Ultra Fine, SG1.
}}}
=== Gridtype ===
{{{#!wiki
  DFT grid type control, integer.
   * 0,  Radial(new kind Chebeshev used by Becke) Angular(Lebedev).
   * 1,  Radial(Chebeshev)                        Angular(Lebedev).
   * 2,  Radial(Eular-Maclarin)                   Angular(Lebedev).
   * 3,  Radial(ut_rad)                           Angular(Lebedev).
  Default: 0
}}}
=== Partitiontype ===
{{{#!wiki
  DFT grid partition type control, integer.
    0:  Becke partition.
    1:  Stratmann-Scuseria-Frisch partition.
  Default: 0
}}}
=== Numinttype ===
{{{#!wiki
  Numerical integration code control, in form x*10+y.
   * y: 0, use default numerical integration code, else debug old numerical integration code.
   * x: print control parameter for default numerical integration code, only useful when y==0
  Default: 0
}}}
=== NoSymGrid ===
{{{#!wiki
  Do not use symmetry dependent grid. Only for debugging.
}}}
=== DirectGrid ===
{{{#!wiki
  Use DirectGrid. Basis set values on the grid points are calculated directly.
  Default: Direct SCF, use direct grid.
  None Direct SCF, do not use direct grid.
}}}
=== NoDirectGrid ===
{{{#!wiki
  Force to do not use direct grid.
}}}
=== NoGridSwitch ===
{{{#!wiki
  For direct SCF, DFT grid can be switched. At the beging of iteration, Ultra coarse grid will be used.
  After energer change is little than a value, such as 1.d-4, the medium grid or user setted grid
  will be used. NoGridSwitch dissiable grid switch and use default grid directly.
}}}
=== ThreshRho ===
{{{#!wiki
 When use debug numerical integration (see NUMINTTYPE):
  If the numerical integral <<latex($\rho_{\mu}^k<threshRho$)>>, the basis <<latex($\chi_{\mu}$)>> will be neglected at grid batch k.
  The <<latex($\rho_{\mu}^k$)>> is defined as
     <<latex($\rho_{\mu}^k=\sum_{i\in batch k} w_i*\chi_{\mu}(r_i)\chi_{\mu}(r_i)$)>>
  Default value: <<latex($ThreshRho=\frac{thresh\_{ene}}{maxradgrid*maxanggrid*natom}$)>>
 When use default numerical integration:
  Neglect the basis <<latex($\chi_{\mu}(r)$)>>, if <<latex($r\geq r_{\mu}$)>>.
  The <<latex($r_{\mu}$)>> is defined as
     <<latex($f(r_{\mu})=\int_{r_{\mu}}^{\infty} \chi_{\mu}^2 r^2dr = ThreshRho$)>>
  If input values is <<latex($\eta$)>>,
   <<latex($ ThreshRho = \left \{ \begin{array}{ll} 10^{-10} & default \\ 10^{-\eta} & \eta \geq 1 \\ \eta & \eta < 1 \end{array} \right. $)>>
}}}
=== ThreshBSS ===
{{{#!wiki
 Only useful when use default numerical integration.
  Neglect the basis <<latex($\chi_{\mu}(r)$)>> at grid batch k, if <<latex($f_{\mu}\leq ThreshBSS$)>>.
  The <<latex($f_{\mu}$)>> is defined as
     <<latex($f_{\mu}=\sum_{r_g \in k} |\chi_{\mu}| \sqrt{w(r_g)}$)>>
  If input values is <<latex($\eta$)>>,
   <<latex($ ThreshBSS = \left \{ \begin{array}{ll} min(10^{-8}, \sqrt{ThreshRho}/N) & default,\ N=\frac{NumberOfGridBatch\times 10}{NumberOfAtom} \\ 10^{-\eta} & \eta \geq 1 \\ \eta & \eta < 1 \end{array} \right. $)>>
}}}
=== MPEC ===
{{{#!wiki
 Integer number, control parameter for generation of Coulomb (Vc) and Nuclear attraction (Vn) matrix.
  in form: jop*1000+kop*100+iop
  default value 0, i.e. not use MPEC.
  When do SCF with MPEC, recommend input -1 (equal to input 4 for SCF), or just use MPEC+COSX.

  NOTE, when do Hartree-Fock or Hybrid DFT with numerical integration of coulomb matrix, must use sketeleton matrix method to do 2e-integral, i.e., need keywork skeleton in module Compass.

 * kop :
  * 0 get Vn matrix by analytical integration.
  * 1 get Vn matrix by numerical integration.
 * jop and iop:
  <<latex($ \begin{array}{cccc} jop & First-SCF-Iter & middle-SCF-Iter & Final-SCF-Iter \\ 0 & ERI^c & OMPEC         & Method(iop)\\ 1 & ERI^b &OMPEC& Method(iop)\\ 2 &ERI^c& Method(iop)& Method(iop)\\ 3&ERI^b& Method(iop) & Method(iop)\\ 6 & OMPEC(mV_c^0) & OMPEC & OMPEC\\ 7 & OMPEC(aV_c^0) & OMPEC & OMPEC  \end{array} $)>>

   * <<latex($ERI^a$)>>: (uv|rs) D_{rs}, D_{rs} ==>               Atom  diagonal D matrix
   * <<latex($ERI^b$)>>: (uv|rs) D_{rs}, D_{rs} ==>               Shell diagonal D matrix
   * <<latex($ERI^c$)>>: (uv|rs) D_{rs}, D_{rs} ==> Atom Occupied shell diagonal D matrix
   * <<latex($ERI_d$)>>: (uv|rs) D_{rs}, u and v belong to one atom, same as r and s
   * OMPEC : Original MPEC method, full numerical
   * ACP   : Analytical Coulomb Potential at grid
   * <<latex($mV_c^0$)>> : model coulpot got by modpotz
   * <<latex($aV_c^0$)>> : model coulpot got by ACP (Atom Occupied shell diagonal D)
   * Method(1) == <<latex($ERI^a$)>>+OMPEC
   * Method(2) == <<latex($ERI_d$)>>+OMPEC,
   * Method(3) ==      OMPEC for <<latex($\Delta\rho$)>>
   * Method(4) == ACP +OMPEC for <<latex($\Delta\rho$)>>
   * Method(5) == Full ERI (the final Iteration) or OMPEC (middle iteration)
}}}
=== Coulpotlmax ===
{{{#!wiki
  Max L value for coulomb potential multipolar expansion.
  Default value: 8
}}}
=== Coulpottol ===
{{{#!wiki
  Cutoff threshold parameter for coulomb potential multipolar expansion, more higher more accurate.
  Default value: 8.
}}}
=== MPEC+COSX ===
{{{#!wiki
  Invoke both MPEC and COSX. It may be requested in Compass now.
}}}
== SCF convergence ==
=== MAXITER ===
{{{
The maximum Number of SCF iteration. Default: 100.
}}}
=== NODIIS ===
{{{
Logical control parameter. Disable DIIS.
}}}
=== XIISID ===
{{{
Set DIIS algorithm. XIISID=0, DIIS; XIISID=1, LCIIS.
Default: XIISID=0.
}}}
=== MaxDiis ===
{{{#!wiki
  Maxim number of Diis space. Default: 8
}}}
=== THRENE ===
{{{#!wiki
  Convergence threshhold for energy. Default: 1.d-8.
}}}
=== THRDEN ===
{{{#!wiki
  Convergence threshhold for RMS change of density matrix. Default: 5.d-6.
}}}
=== ThreshConv ===
{{{#!wiki
  Convergence threhhold.
  Two float values: DeltaE  DeltaD
}}}
{{{
$SCF
threshconv
1.d-6 1.d-4
$END
}}}
=== THRDIIS ===
{{{#!wiki
 Threshold to turn on DIIS. Default: 0.15.
}}}
=== DIISmode ===
{{{
DIISmode:
0: diisdim goes from 0 to maxdiis, then cycles to 0. And reset to 0 when diis fails.
1: diisdim goes from 0 to maxdiis, keeps maxdiis. And throw the oldest vector (reduce diisdim) when diis fails.
Default: 0.
}}}
=== Vshift ===
{{{#!wiki
  Level shift value (unit: au). Recommended range: 0.2-1.0. Default: 0.
}}}
=== Damp ===
{{{#!wiki
 Damping value. Valid range: [0,1). The larger the damping value is, the smaller the SCF step will be. Default: 0.
}}}
=== SMH ===
{{{#!wiki
 Invokes the Semiempirical Model Hamiltonian (SMH) converger. Can be used in conjunction with DIIS, damp or vshift. On average, SMH reduces the number of SCF iterations by 10-15 %, with the largest savings observed in systems with charge transfer character and/or strong correlation, where savings can reach 30 % to 6 fold. At this point, the SMH converger is available for RHF/RKS and UHF/UKS, but not for ROHF/ROKS. Besides, the SMH converger cannot be used when Fermi smearing is turned on, or when the basis set is linearly dependent. '''NOTE: SMH is turned on by default whenever it is supported.'''
}}}
=== NoSMH ===
{{{#!wiki
 Disable SMH.
}}}
=== Icheck ===
{{{#!wiki
 Check Aufbau law.
}}}
=== IAUFBAU ===
Control parameter of electron occupation protocol in each SCF iteration. IAUFBAU = 1, electron occupation obeys Aufbau principle(default); IAUFBAU = 2, electrons complies with specific occupation pattern based on maximum occupation method(mom); IAUFBAU = 3, electrons complies with specific occupation pattern based on maximum occupation method(mom). Update MO coefficients and reorder occupied orbitals in each iteration.   WARNING if IAUFBAU=2 or 3 without initial guess=read (this means initial guess is bad), the result is unpredictable.

=== Smeartemp ===
Temperature (in Kelvin) used in Fermi smearing. A realistic temperature (e.g. 300 K) allows one to probe the finite-temperature effects of the electronic structure, while much higher temperatures (5000 K for pure functionals, 10000 K for hybrid functionals, or 20000 K for HF) may be useful for stabilizing SCF convergence. Note that the final energy includes the electronic entropy contribution, which is printed in the "Final scf result" section under the name "-TS_ele". Subtracting this contribution from the final energy (E_tot) gives the electronic energy. '''Note: Smeartemp must not be used together with vshift and/or SMH, nor can it be used in bottom-up FLMO calculations or other calculations where the keyword sylv is set to a non-zero value.'''

== Fock diagonalization ==

=== sylv ===
Block-diagonalize the Fock matrix by solving the Sylvester equation (recommended when the Fock diagonalization time takes a significant fraction of the total computational time, and the basis set is small, e.g. minimal or double zeta). This automatically sets Blkiop=3.

=== iviop ===
Diagonalize the Fock matrix using the iVI method (recommended when the Fock diagonalization time takes a significant fraction of the total computational time, AND the basis set is large, e.g. at least triple zeta). 1：CHC rotation with Fock screen, automatic switch betwwen iVI and Dsyev. 2：iVI for GEP (generalized eigenvalue problem) diagonalization. 3：iVI for EP (eigenvalue problem) with Cholesky decomposition of S.

=== Blkiop ===
7 and 8 for iVI diagonalization otherwise specific pFLMO diagonalization: 1: SAI, 2: DDS, 3: DNR, 4: DGN, 5: FNR, 6: FGN 8: CHC rotation with Fock screen, full diagonalization 7: iVI diagonalization, specific by iviop. Recommended value of Blkiop: 3

== Print and output SCF orbital ==
=== print ===
 . Print level.

=== iprtmo ===
 . Print MO coefficients. Values: 0 - do not print MO coefficients, 1 - print the MO coefficients of frontier orbitals (HOMO-5 to LUMO+5 of each irrep). 2 - print the MO coefficients of all orbitals.

=== Noscforb ===
 . Not output SCF orbital in .scforb file.

=== Pyscforb ===
 . Output SCF orbital into Pyscf format file.

=== Molden ===
 . Output SCF orbital into Molden format file.

== Relativistic properties ==
 . The following relativistic properties have been programmed for the X2C Hamiltonian (Heff must be 21, 22, or 23).

=== RelED (effective contact density) ===
 . Calculate effective contact densities for the atoms with ZA ≥ minza. The finite nucleus model must be used which is specified in [[xuanyuan]] .

 . '''NOTE''' The effective contact densities are very sensitive to basis functions. Very steep primitive s-functions (and p-functions for p-block elements) have to be used to get accurate results.

=== RelEFG (electric field gradient) ===
 . Calculate electric field gradient (EFG) tensor and nuclear quadrupole coupling constant (NQCC) for the atoms with ZA ≥ minza. The finite nucleus model must be used which is specified in [[xuanyuan]] .

 . '''NOTE''' The EFG tensor is very sensitive to basis functions. Both steep and diffuse primitive s, p, d, and f-functions, if they are involved in the occupied atomic orbitals, have to be used to get accurate results. In addition, (static and dynamic) electronic correlations are also important for EFG. For example, EFG of a degenerate state by HF/DFT may be unreliable.

An example,

{{{
$xuanyuan
scalar
heff
 23
nuclear
  1
$end

$scf
 rhf
 reled
   10
 relefg
   10
$end
}}}

== Expert keywords ==
=== IfNoDeltaP ===
 . Dissable using DeltaP to update Fock matrix.

=== IfDeltaP ===
 . Delta P is used to update density matrix. In direct SCF calculation, delta P will be used in integral prescreening instead of P. Default: true.

=== Optscreen ===
 . For debugging. Set a strict threshold (thresh_rho=1.d-4) for integral prescreening directly.

=== Nok2Prim ===
{{{#!wiki
  Disable primative integral screenning via K2 integrals. Use (SS|SS) esitimating primative integral
  value and perform screening.
  Default: Direct SCF, use K2 primative screening.
           None Direct SCF, use (SS|SS) integral.
}}}
=== FixDif ===
 . Fix factor for incremental fock update. If the factor is not fixed, use the formular

<<latex($fac=1-\frac{D^{n+1}-D^n}{D^{n+1}*D^{n+1}}$)>>

<<latex($F^{n+1}=F^n+fac*\delta F$)>>

 . if using fixed factor, fac=1.d0.

=== Jengin ===
{{{#!wiki
 Use Jengin method calculate J matrix. In debugging, not support now.
}}}
=== LinK ===
{{{#!wiki
 Use LinK calculate K matrix. In debugging, not support now.
}}}
=== Cutlmotail ===
{{{#!wiki
  Methods to cut long Coulomb tails of Local molecular orital.
  Values: -1 Do not cut tail.  1 Project a LMO into fragment with largest Lowdin population.
           2 Similar with 1, but project a LMO into predefined group of fragments with largest Lowdin population.
           3 Very stick cutoff. Project LMO to a fragment plus several atoms. The threshhold is 1.d-4.
  Comment: Method 1 is prefered if fragments are well defined. We can easy reduce compuations times in post
           SCF calcualtion based on LMO because diffirent fragment interaction policy can be predefined, which
           will reduce ERIs need to be calculated.
}}}
=== CHECKLIN ===
{{{#!wiki
Check if the basis sets is linear dependent. If diffuse basis set is used, SCF do not converge or ridiculous energy observed, it is better to check linear dependent of the basis set.
}}}
{{{
$SCF
checklin
$END
}}}
=== TOLLIN ===
{{{#!wiki
Tolerance of basis set linear dependent. Default value 1.d-7.
}}}
{{{
$SCF
tollin
1.d-5
$END
}}}
=== ifPair ===
{{{#!wiki
used to excite electrons (MOM)with following keywords:<<BR>>
hpalpha,hpbeta<<BR>>
then with number of partical-hole pairs N<<BR>>
then with 2N lines specificate partical-hole pairs. (0 is do nothing, indexes start from 1)<<BR>>
eg. the molecular is has 4 irreducible representation, we want to excite electrons from orb 5,6 to 8,9 in rep 1 and 3 to 4 in rep 3 (alpha) & 7 to 8 in rep 1(beta):
}}}
{{{
ifpair
hpalpha
2
5 0 3 0
8 0 4 0
6 0 0 0
9 0 0 0
hpbeta
1
7 0 0 0
8 0 0 0
}}}
{{{#!wiki
this should be combined with iaufbau=2 or 3.<<BR>>
WARNING: this function will not check whether partical orbital is filled or whether hole orbiltal is not filled.
}}}
=== pinalpha , pinbeta ===
{{{#!wiki
specificate fix orbitals<<BR>>
first line specificates the number of fix orbitals<<BR>>
then with N lines specificate fix orbitals. (0 is do nothing, indexes start from 1)<<BR>>
(somewhat likes hpalpha/hpbeta input)<<BR>>
these keywords leads to SCF_solver from solve FC=SCE to <<latex($\tilde{F}U=UE,\tilde{F}=C^\dagger FC$)>> <<BR>>
}}}

=== RSOMEGA ===
Set parameter omega in RS Hybrid functional as CAM-B3lyp, LC-Blyp, etc. Only used in debugging.

=== RSALPHABETA ===
Set alpha, beta parameters in RS Hybrid functionals. Only used in debugging.

= Depend Files =
||Filename ||Description ||Format ||
|| || || ||


= Examples =
== How to perform a direct DFT calculation with B3LYP functional? ==
{{{
$COMPASS
Title
 Cocaine Molecule test run, CC-PVDZ
Basis
  CC-PVDZ
Geometry
  XYZ               # The molecule geometry will be read from file $BDFTASK.xyz
End Geometry
Skeleton          # This keyword must be used.
$End

$xuanyuan
Direct              # Direct SCF.
Schwarz          # Schwarz prescreening.
$end

$scf
RKS
DFT functional
 B3LYP
Molden     # This keyword is used to output SCF orbital to molden format file.
$end
}}}
== How to read molecular orbital as initial guess orbital or restart SCF calculation? ==
Suppose you have performed a calculation and generated aSCF orbital file in your work directory as test.scforb. Usually, this file atomically generated by SCF module. This file also can be used to restart SCF calculation via read it as initial guess orbital.

{{{
$COMPASS
Title
 Cocaine Molecule test run, CC-PVDZ
Basis
  CC-PVDZ
Geometry
  XYZ    # The molecule geometry will be read from file $BDFTASK.xyz.
End Geometry
Skeleton          # This keyword must be used.
$End

$xuanyuan
Direct              # Direct SCF.
Schwarz          # Schwarz prescreening.
$end

# Copy orbital file test.scforb as inporb in BDF_TMPDIR
% cp $BDF_WORKDIR/test.scforb $BDF_TMPDIR/inporb

$scf
RKS
DFT functional
 B3LYP
Guess       # Read orbital as  initial guess orbital
 Read
Molden     # This keyword is used to output SCF orbital to molden format file.
$end
}}}
== How to accelarate SCF and TDDFT calculation with Multipole Expansion of Coulomb Potential (COULPOT) and Chain-Of-Sphere eXact exchange (COSX)? ==
In HF/DFT calculation, the J and K matrices could be calculated with the different algorithms. One can calculate J and K operators with four-index electron repulsion (denote as J-ERI and K-ERI). One can also calculate J operator by using multipole-expansion to calculate coulomb potential (J-Coulpot). Coulpot is much faster than J-ERI. For K matrix, one can also use Chain-of-Spheres for exchange (K-COSX) scheme introduced by Frank Neese. Therefore, there are possible four combination to calculate J+K operatros in BDF. Here is example input.

{{{
###
# Molecule: Trypophane
#  DFT/B3lyp, Direct SCF/ERI, Direct SCF/Coulpot+COSX,
###
$COMPASS
Title
 Trypophane Molecule test. Different SCF algoritm
Basis
 def2-svp
Geometry
C    -5.180310    1.350093   -0.761602
N    -4.541127    1.810914    1.512755
C    -4.214871    1.026972    0.352222
C    -4.314616   -0.453360    0.696018
C    -2.985178   -1.107032    0.480801
C    -2.691578   -2.435732    0.687001
N    -1.371378   -2.626032    0.374901
C    -0.802178   -1.440032   -0.031299
C     0.506322   -1.158132   -0.441399
C     0.800622    0.160368   -0.802499
C    -0.175278    1.153768   -0.754599
C    -1.479078    0.854668   -0.341999
C    -1.799378   -0.466032    0.026601
O    -6.055556    2.163783   -0.585200
O    -5.066908    0.735342   -1.944592
H    -3.986324    1.717755    2.363587
H    -5.327349    2.460137    1.485110
H    -3.177889    1.263584    0.024424
H    -4.615011   -0.566763    1.761696
H    -5.075156   -0.935542    0.041917
H    -3.392007   -3.207186    1.039501
H    -0.866143   -3.544417    0.436596
H     1.274481   -1.944628   -0.478218
H     1.818909    0.417434   -1.129621
H     0.081435    2.183514   -1.043948
H    -2.245318    1.643076   -0.306108
H    -5.688781    0.943476   -2.662045
End geometry
Check
skeleton
$END

$XUANYUAN
direct
schwarz
$END

#This is a DFT calculation with J-ERI + K-ERI
%echo "CHECKDATA: RKS with ZY-NI and ERI"
$SCF
RKS
dft functional
 b3lyp
$END

#This is a DFT calcualtion with J-Coulpot + K-ERI
%echo "CHECKDATA: RKS with ZY-NI, Coulomb potential+COSX"
$SCF
RKS
dft functional
 b3lyp
COULPOT
$END

#This is a DFT calcualtion with J-ERI + K-COSX
%echo "CHECKDATA: RKS with ZY-NI, Coulomb potential+COSX"
$SCF
RKS
dft functional
 b3lyp
COSX
$END

#This is a DFT calcualtion with J-Coulpot + K-COSX
%echo "CHECKDATA: RKS with ZY-NI, Coulomb potential+COSX"
$SCF
RKS
dft functional
 b3lyp
COULPOT+COSX
$END
}}}