In this exercise, we will examine some of the 'post-processing' that you can do once you have run your scf calculations.

In the previous exercise, there was only one output quantity that we cared about ...the total energy. Here we will see some other things that we can extract from the files produced when one does a PW calculation...e.g., charge densities, and eigenvalues (which we will use to get band structure plots and densities of states). We will continue to work with Si, which was the subject of exercise1.
Enter the directory ex2. You will see the following files:

Self-consistent (scf) calculations for Si

Run the scf calculation:

    pw.x < > Si.scf.out

Band structure of Si

Run a 'bands' calculation:

pw.x < >

What differences do you see between the output file you obtain here, and the output file that you obtained from your scf calculation?

Collect band results for plotting


bands.x < > bands.out

Have a look at bands.out and bands.dat and note the minimum and maximum energy eigenvalues at different k-points.

Now let's get the data in a format to plot

Charge density for Si

Now we do the post-processing to extract the charge density

Run the post-processing code:

 pp.x < > Si.pp_rho.out

Now make a plot the extracted charge density

Run the plotting code:

      plotrho.x < > Si.plotrho.out

Use ghostview or ggv to view the charge density of Si.

Density of states plot for Si

Run the nscf calculations:

pw.x < > Si.nscf.out

DOS calculations

Run density of states calculations:

dos.x < > dos.out