Two‐Dimensional Charge Densities

Charge densities can be evaluated directly by looking at 2D charge densities. The calculation settings are similar to those for DOS calculations.

Add four commands to the INCAR file:

• LCHARG = .TRUE. Write out the charge density.
• LPARD = .TRUE. Do a partial charge density calculation.
• NBMOD = -3 Energy range for chosen bands will be given in eV.
• EINT = [value1] [value2] The energy range in eV for the bands that will be integrated to get the charge density within this energy range (with respect to the Fermi level). [value1] gives the lower limit of the range, [value2] gives the upper limit of the range.

After the calculation has been finished, copy the CHGCAR file to a suitable folder and open it with VESTA (visit homepage).

On the molecular viewer, select three atoms (with the angle selection tool on the left) which are located on the plane that shall be cut through and looked at with the 2D density plot. If only two atoms are located on the plane, widen the view to two unit cells in the respective direction (e.g., z-axis) with the boundary tool and select one of the periodic copies of the first or second atom as the third atom.

Then, go to Utilities -> 2D Data Display and click on the Slice button in the new window. There, click on Calculate the best plane for the selected atoms. Now, a new window should open which shoes a color-gradient density plot (blue: low density, red: high density). The color scale can be changed with the Saturation Levels toolbox. Further, Contour Lines can be drawn by activating them in the Contours category. There, a scale of maximum and minimum density values can be set as well.

Finally, go to File -> Export Raster Image.