Hartree-Fock calculation

Setting up an HF calculation

A Hartree-Fock (HF) calculation is performed by specifying a HF wavefunction in the method section of the input file. Available HF methods are RHF (hf), UHF (uhf), and MLHF (mlhf). E.g., for a RHF calculation we write

end method

At the HF level, single-point calculation and geometry optimization can be performed. To select one of them, specify either ground state or ground state geoopt in the do section. E.g., for a single-point calculation

   ground state
end do

A minimal working example for an RHF single-point calculation on water:

   name: H2O
   charge: 0
end system

   ground state
end do

end method

basis: cc-pVDZ
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 h2o.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 h2o.out and h2o.timing.out in your working directory. Obtaining the timing file can be suppressed by specifying the -nt flag after eT_launch. 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 Hartree-Fock equations. The table with the iteration information should end with something like this:

7           -75.989795840960     0.5997E-05     0.2341E-07
8           -75.989795841698     0.2378E-05     0.7377E-09
9           -75.989795841773     0.2055E-06     0.7489E-10
Convergence criterion met in 9 iterations!

Including the solver scf section in the input allows to specify the settings of the HF calculation, as e.g. the energy or gradient thresholds, in more detail. You may want to loosen the thresholds for the HF calculation as the default energy and gradient thresholds (\(10^{-6}\)) are chosen to be rather tight. If you also want to get the molecular orbital coefficients, the print orbitals keyword has to be specified in this section.

solver scf
  energy threshold:   1.0d-4
  residual threshold: 1.0d-4
  print orbitals
end solver scf

The orbital coefficients are written to a separate file which is automatically copied to the working directory by eT_launch. The orbital coefficient file would be called h2o_mo_coefficients.out in this example.

Relevant input sections

Solver SCF

HF mean value