After the DFT calculation is completed, a DOSCAR output file should be present in the directory. The DOSCAR output file contains the electronic DOS and integrated DOS of the surface as well as the projected DOS for each atom. Additional details about the DOSCAR output file can be found on the VASP wiki.

Using the vasprun.xml output file and the (Python) script provided, the total DOS plot and a PDOS plot can be generated to visualize the DOS for the surface. Below are figures depicting the total DOS and PDOS for the Pd (111) surface. (Must caption)

With the DOSCAR output file and the split_dos script, the DOSCAR file can be decomposed into the multiple DOS files (DOS1, DOS2,…,DOSn) for each atom in the system numbered corresponding to each atom number in the POSCAR file. Below is an example of a DOS file for a Pd atom in the Pd (111) surface with headings added to better understand what each column represents. In the original DOS file, there are no headings present.

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Using the DOS file for an atom on the surface and the provided Excel spreadsheet, the d band center can be calculated using the following formula ¹,

\[\frac{\int \rho EdE}{\int \rho dE}\]

where \(\rho\) is d-band density, \(E\) is the d-band energy, and \(\rho dE\) is the number of states. It is important to choose a DOS file for a surface atom (if possible, where the adsorbate will bind to) to calculate the d-band center as this will be where the adsorption and reaction chemistry will most likely occur.

The two input parameters required for the spreadsheet to calculate the d-band center for a given surface are the energy and d-DOS columns from the DOS file. Below is a snapshot of the spreadsheet with the input columns and the various columns to be calculated. The spreadsheet will then calculate the values for the fraction of states  that are associate with the d band and the total number of states. At the bottom of the spreadsheet, the value of the d band will be listed. For the Pd (111) example surface, the d-band center was calculated to be -1.59 eV.

References