Multilevel Hartree-Fock calculation¶
Setting up an MLHF calculation¶
To run an MLHF calculation, the method
mlhf must be specified in the method section.
method mlhf end method
Furthermore, you must request a
ground state calculation in the do section.
do ground state end do
As MLHF calculations run in the MO basis, it is also necessary to specify
mo-scf-diis algorithm in the solver scf keyword section.
solver scf algorithm: mo-scf-diis end solver scf
Additionally, an active atom space has to be defined through the active atoms section.
In this section a
selection type has to be chosen. The options are
For MLHF this keyword is followed by the keyword
hf (for Hartree-Fock) where the active atoms are specified.
list a list of numbers has to be specified where each number refers to an atom in the geometry.
range 2 numbers has to be specified where each number refers to an atom in the geometry.
All atoms from the first to the second number are selected.
selection type: central atom one atom central atom is chosen by giving a number to the
central atom keyword.
The active atoms are chosen depending on the range from this central atom. The range is given as floating point number in the
A minimal working example for an MLHF single-point calculation on 2 water molecules can be found below. The first water molecule (atoms 1, 2 and 3) is selected as active while the other water molecule is inactive.
system name: 2 waters end system method mlhf end method do ground state end do solver scf algorithm: mo-scf-diis end solver scf active atoms selection type: range hf: [1,3] end active atoms geometry basis: aug-cc-pVDZ H 0.86681 0.60144 5.00000 H -0.86681 0.60144 5.00000 O 0.00000 -0.07579 5.00000 H 0.86681 0.60144 0.00000 H -0.86681 0.60144 0.00000 O 0.00000 -0.07579 0.00000 end geometry
Save this as
2_waters.inp and type the following command in your terminal (here shown for four threads)
eT_launch --omp 4
After the calculation finished you should find
2_waters.timing.out in your working directory.
Obtaining the timing file can be suppressed by specifying the
-nt flag after
If the calculation exited successfully (look for
eT terminated successfully! at the bottom of the file),
the output file should show iteration information for the solver converging the MLHF equations.
The table with the iteration information should end with something like this:
... 7 -151.950133335899 0.1229E-04 0.3615E-08 8 -151.950133335979 0.1492E-05 0.8060E-10 9 -151.950133335983 0.3509E-06 0.3524E-11 --------------------------------------------------------------- Convergence criterion met in 9 iterations!
An optional multilevel hf section can be specified in an MLHF calculation to request specific settings such as generating Cholesky active virtual orbitals, an initial full space HF optimization to a given threshold, or a projection on a minimal basis. In this last case, the section would look like the following example:
multilevel hf project on minimal basis end multilevel hf