Scf

HF/DFT.

General keywords

RHF/UHF/ROHF

• Must input one of them if Hartree-Fock calculation is required. Require for restricted/unrestricted/restricted open shell Hartree-Fock calculations.

Example:

$Scf
RHF
$end

RKS/UKS/ROKS

• Must input one of them if Kohn-Sham calculation is required. Require for restricted/unrestricted/restricted open shell Kohn-Sham calculations.

Occupy

• Used in RHF/RKS. Set double occupied number of each irreps. The following line is an integer array, $noccu(i),i=1,\cdots, nirreps$.

Alpha

• Used in UHF/ROHF/UKS/ROKS. Set number of alpha orbitals in each irreps. The following line is an integer array, $nalpha(i),i=1,\cdots, nirreps$.

Beta

• Used in UHF\/ROHF\/UKS\/ROKS. Set number of alpha orbitals in each irreps. The following line is an integer array,$ nbeta(i),i=1,\cdots , nirreps$.

Charge

• Charge of the state.

Spin

• Spin of the state. The value is 2S+1.

keyword

DFT functional keywords

DFT

• DFT functional used in Korn-Sham calculation. Commonly used functionals: SVWN5, BLYP, B3LYP, CAM-B3LYP, etc.

• LSDA:
  • ex_fun=1 co_fun=1
  SVWN5:
  • ex_fun=1 co_fun=2
  PW91:
  • ex_fun=3 co_fun=3
  SAOP:
  • ex_fun=30 co_fun=30
  BLYP:
  • ex_fun=4 co_fun=8
  BHHLYP
  • ex_fun=21 co_fun=8
  B2PLYP
  • ex_fun=22 co_fun=8
  B3LYP
  • ex_fun=20 co_fun=0
  LC-BLYP
  • ex_fun=104 co_fun=8
  CAM-B3LYP
  • alpha=0.19d0 beta=0.46d0 ex_fun=120 co_fun=0

RS

• Alpha and beta value in CAM calculation. The following line are two float number. For example : 0.33 0.15

D3

• Grimmers dispersion corrrection for DFT.

DFT grid keywords

NPTRAD

• Number of radius grid points.

NPTANG

• Number of angular grid points.

Grid

• Set DFT grid. Support values are: Ultra Coarse, Coarse, Medium, Fine, Ultra Fine, SG1.

NoSymGrid

• Do not use symmetry dependent grid. Only for debugging.

DirectGrid

• 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

• Force to do not use direct grid.

NoGridSwitch

• For direct SCF, DFT grid can be switched. At the beging of iteration, Ultra coase 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

• If the numerical integral , the basis will be neglected. The is defined as

  • 

  Default value:

SCF convergence

Maxiter

• Number of maxim iterations in SCF.

Nodiis

• Disable DIIS.

MaxDiis

• Maxim number of Diis space. Default: 8

THRENE

• Convergence threshhold for energy. Default: 1.d-8.

THRDEN

• Convergence threshhold for density matrix. Default: 3.d-6.

ThreshConverg

• Convergence threhhold. Two float value: DeltaE DeltaD

THRDIIS

• Threshold to turn on DIIS. Default: 0.15.

Vshift

• Level shift value.

Damp

• Damping value.

Icheck

• Check Aufbau law.

iAufbau

• Enable or disable Aufbau law to change orbital occupation number in SCF iteration.

FOA FCA FVA

Print and output SCF orbital into Molden format

print

• Print level.

iprtmo

• Require to print MO coefficients. Values: 1 Only print orbital energy and occupation numbers. 2 Print all information.

Molden

• Output SCF orbital into Molden format file.

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

• 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 \begin{align*}

  • fac=1-\frac{D^{n+1}-Dn}{D^{n+1}*D{n+1}} \\ F^{n+1}=Fn+fac*\delta F

  \end{align*} if using fixed factor, fac=1.d0.

Jengin

• Use Jengin method calculate J matrix. In debugging, not support now.

LinK

• Use LinK calculate K matrix. In debugging, not support now.

Guess

• Method to get initial guess orbital. The following line is a string.
  • Values: Atom, Hcore, Huckel, Read. If Read is used, the old orbital will be read. The old orbital saves in a file named "inporb" in BDF_TMPDIR . It is generated by previous SCF calcualtion with the name Task.scforb.

Cutlmotail

• 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

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.

ΤΟLLIN

Tolerance of basis set linear dependent. Default value 1.d-7.

Depend Files

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 molecule orbital as initial guess orbital or restart SCF calculation?

  Suppose you have perform a calculate name with a SCF 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