Hartree-Fock calculation

If you have not already done so, you should take a look at the eT_launch page to get an understanding of how the launch script works.

Setting up an HF calculation

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

- method

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

- do
  ground state

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

- do
  ground state

- method

- geometry
  basis: cc-pVDZ
  H          0.86681        0.60144        0.00000
  H         -0.86681        0.60144        0.00000
  O          0.00000       -0.07579        0.00000


For open-shell calculations you might want to specify the multiplicity in the system section. The default multiplicity is 1.

Save this as h2o.inp and invoke the launch script.

path/to/eT_launch.py h2o.inp

After the calculation finished you should find h2o.out and h2o.timing.out in your working directory. 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 residual thresholds, in more detail. You may want to loosen the thresholds for the HF calculation as the default energy and residual thresholds (\(10^{-7}\)) are chosen to be rather tight. If you also want to get the molecular orbital coefficients, the write orbitals keyword has to be specified in this section.

- solver scf
  energy threshold:   1.0d-4
  residual threshold: 1.0d-4
  write orbitals

The orbital coefficients are written to a separate file which is automatically copied to the output directory by the launch script. The orbital coefficient file would be called h2o.mo_coefficients.out in this example.

If you wish to compute Mulliken or Loewdin (or both) population analysis you need to add the keyword population analysis: in the solver scf and then specify mulliken, loewdin or all. The population analysis will be saved in separate files, which in this example would be called h2o.Mulliken_population_analysis.out and h2o.Loewdin_population_analysis.out where you can find the atomic charges and reduced orbital charges.

- solver scf
  population analysis: mulliken

Relevant input sections

Solver SCF

HF mean value

Solver geometry optimization

System section