Similarly to the exercise 1.2, we are going to calculate the convergence with respect to the forces acting on th atoms, but this time changing the dimension of the kpoint grid like in exercise 1.3.
- Copy the provided input files into this folder
cp ../../files/NaCl.scf.in . - Copy or link the pseudopotential files for Na and Cl inside a folder named
pseudoin the same path of the input file
cp -r ../../files/pseudo/ . - Modify the input file to use the converged cutoff you obtained in either problem 1.a or 1.b
- Run the code pw.x from terminal using the command
pw.x < Na.scf.in > Na.scf.out - Collect the value of the forces acting on the two atoms (you expect to have the x and y components equal to 0 and that fz_Na = - fz_Cl).
The lines containing this information in the output file will look like this:
atom 1 type 1 force = 0.00000000 0.00000000 0.02365046 - Increase the size of the kpoint grid by steps of 2 (e.g. 2x2x2 -> 4x4x4 -> 8x8x8).
- Repeat points 4 through 6 until a convergence of 10 meV/Angstrom achieved.
TIP: You can modify the bash script provided in this repository to automate this process or write your own script in any scripting language.