Example

Generation of pseudopotentials is illustrated for the case of a carbon atom. Please set the keyword, calc.type, to VPS in the input file C.inp, and perform as follows:

     % adpack C.inp
  

When the calculation is completed normally, the following seven files newly generate in the directory, work.

   C0.nsvps        non-separable pseudopotentials
   C0.vps          input file, results of the SCF calculation, and pseudopotentials
                   in the KB or Blochl separable form,
                   and partial core density for PCC
   C0.vpao         radial parts of pseudo-atomic orbitals for pseudopotentials
   C0.vden         valence electron density, the total electron density,
                   core electron density,
                   modified core electron density for PCC
   C0.loc          local part of pseudopotentials
   C0.ld0          logarithmic derivatives of wave functions(l=0).
   C0.ld1          logarithmic derivatives of wave functions(l=1).

C0.nsvps
In a file, C0.nsvps, the pseudopotentials in a non-separable form are output, in which they are listed in order of log (r), r, the pseudopotential 0, and the pseudopotential 1, ..., where the number referred to specify the pseudopotential corresponds to the number given for the first column in the specification of the keyword, pseudo.NandL, in the input file. Figure 2 shows the pseudo potentials of a carbon atom stored in the file, C0.nsvps.
C0.vps
In a file, C0.vps, the pseudopotentials in a Blöchl separable form are output, in which they are listed in order of log (r), r, the local part of the pseudopotential, and the non-local part of the pseudopotential. Also, the input file and the results of the SCF calculation are added in this file for your adversaria. The file is output in the flexible data format, since the file *.vps is used for the input file to the program package, OpenMX. In Fig. 2(b) shows the Blöchl separable pseudopotentials of a carbon atom. In case of charge.pcc.calc=ON, then the file also includes the partial core density for PCC [10]. The format is the same as that of the pseudopotential, and they are listed in order of log (r), r, and the partial core density. The data of the partial core density is also used as the input date of OpenMX. In Fig. 3, the partial core density is shown together with the valence electron density stored in the file, C0.vden.
C0.vpao
The pseudo-atomic orbitals corresponding to the pseudopotentials are output in a file, C0.vpao. The format of the output is the same as that of C0.nsvps. Figure. 2(a) shows the pseudo-atomic orbitals and the pseudopotentials.
C0.vden
The electron density for the valence electron is stored in a file, C0.vden.
In case of charge.pcc.calc=OFF, the data are output in order of
log(r), r, $\rho_{\rm v}$, $\rho_{\rm t}$, $\rho_{\rm c}$, $4\pi r^2\rho_{\rm v}$, $4\pi r^2\rho_{\rm t}$, $4\pi r^2\rho_{\rm c}$.
In case of charge.pcc.calc=ON, the data are output in order of
log(r), r, $\rho_{\rm v}$, $\rho_{\rm t}$, $\rho_{\rm c}$, $\rho_{\rm pcc}$ $4\pi r^2\rho_{\rm v}$, $4\pi r^2\rho_{\rm t}$, $4\pi r^2\rho_{\rm c}$, $4\pi r^2\rho_{\rm pcc}$.
where
$\rho_{\rm v}$: the valence electron density,
$\rho_{\rm t}$: the total electron density,
$\rho_{\rm c}$: the core electron density,
$\rho_{\rm pcc}$: the modified core electron density for PCC.
C0.loc
The local part of separable pseudopotentials is output in the file, C0.loc, in order of log (r), r, and the local part. Figure. 2(b) shows the local part of the pseudopotentials.
C0.ld*
The logarithmic derivatives of radial wave functions are output in the file, C0.ld*, where * means the angular momentum quantum number. The data are stored in order of energy and the logarithmic derivatives of radial wave functions under the all electron potential, semi-local pseudopotential, and fully separable pseudopotential.

Figure: (a) Radial parts of the pseudo-atomic orbitals and the corrsesponding norm-conserving pseudopotentials, (b) Norm-conserving pseudopotentials in a Blöchl separable form

In the generation of pseudopotentials, it is possible to choose either BHS type or TM type. In the template file, C.inp, TM type is chosen as the generation scheme. In practice, the choice of a suitable cutoff radius in the pseudopotential generation is made by a trial and error way so that the shape of the generated pseudopotentials is smooth. Also, it is required to carefully check whether appropriate results are obtained or not in physical quantities that you want to calculate when density functional calculations are performed for molecules and solids using the generated pseudopotentials. In addition to this, there is some ambiguity in the selection of states to generate pseudopotentials, while states, which can form the valence states, are selected in general.

Figure: Valence electron and partial core densities of a carbon atom