All electron calculation

In this section, keywords for the all electron calculation are explained. These keywords discussed here are important for all calculations including the generation of pseudopotentials and pseudoatomic basis functions, since both the generations of pseudopotentials and pseudo-atomic orbitals are based on the all electron calculation. The list of keywords and some comment for the all electron calculation are as follows:

1. xc.type

   Choose GGA, LDA, or LDA-VWN

2. total.electron

   Give the total number of electrons. It is also possible to give the number of electrons corresponding to not only a neutral atom, but also a positive or negative charged atom.

3. grid.xmin

   Set grid.xmin ($r_{\rm min}$(a.u.)=exp(grid.xmin)), where $r_{\rm min}$ is the minimum radius from which radial differential equations are solved toward a distant. An appropriate value for grid.xmin is -7.0 from H to Kr, and -10.0 for heavier atoms.

4. grid.xmax

   Set grid.xmin ($r_{\rm max}$(a.u.)=exp(grid.xmax)), where $r_{\rm max}$ is the maximum radius from which radial differential equations are solved toward the origin. An appropriate value for grid.xmin is 2.5 to 4.0, but could depend on whether there are delocalized states or not.

5. grid.num

   Set the number of grids to solve radial differential equations. A larger number of grids gives a higher degree of accuracy, while the computational time increases. An appropriate value for grid.num is 3000 to 12000. For heavier atoms, the use of a larger number of grids is better to achieve a reliable calculation.

6. grid.num.output

   It is possible to change the number of grids for $r$ in output files by the keyword, grid.num.output, although the actual calculation is performed using grid.num. Usually, we use 500 for it.

7. scf.maxIter

   Set the maximum number of SCF iteration.

8. scf.Mixing.Type

   Choose a method for charge mixing. Either simple, GR-Pulay, or Pulay is available. In most cases, the simple mixing scheme is enough to achieve a sufficient convergence.

9. scf.Min.Mixing.Weight

   Set the minimum mixing weight.

10. scf.Max.Mixing.Weight

    Set the maximum mixing weight.

11. scf.Mixing.History

    Set previous SCF steps for charge mixing in the GR-Pulay or Pulay method.

12. scf.Mixing.StartPulay

    Set a SCF iteration number from which the GR-Pulay or Pulay starts.

13. scf.criterion

    Set scf.criterion. At least 1.0e-10 for the keyword should be chosen for a convergent calculation.