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