DDEC Charges

The DDEC method can be useful for calculating charges of atoms. We have found it to give comparable results to the common Bader charge method[1]. The following are steps to calculating charges with the CP2K program.

1) Obtain the DDEC code here. The latest version is the DDEC6 method. Unpack the files, either to your local computer or our linux machines.

2) Add the following to your CP2K input to generate the correct cube file. This section will be under &DFT -- &PRINT.

  &E_DENSITY_CUBE
       FILENAME valence_density
       STRIDE 1
  &END E_DENSITY_CUBE

3) Copy the final cube file to "valence_density.cube". The DDEC codes requires the cube file to have this name.

4) Create a "job_control.txt" file with the following content. You should edit the location of your atomic_densities folder location. You should also change the section for the atoms that you are modeling.

<periodicity along A, B, and C vectors>
.true.
.true.
.true. 
</periodicity along A, B, and C vectors>

<atomic densities directory complete path>
/home/nadeskins/utils/chargemol_09_26_2017/atomic_densities/ 
</atomic densities directory complete path>

<number of core electrons>
6 2
8 2
</number of core electrons>

5) Run the DDEC code. Pre-built binaries are provided with the package from the DDEC website. For instance run "Chargemol_09_26_2017_linux_serial" for the linux serial code. The parallel version may get much faster results.

6) The charges can be found in "valence_cube_DDEC_analysis.output" where the atom positions, charges, and other information is given.

[1] Iyemperumal, S. K., & Deskins, N. A. (2017). Activation of CO₂ by supported Cu clusters. Physical Chemistry Chemical Physics, 19(42), 28788–28807. https://doi.org/10.1039/C7CP05718K