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--- exercise:bs [2014/05/20 08:53] – pshinde
+++ exercise:2014_ethz_mmm:bs [2014/10/15 12:38] – exercise:bs renamed to exercise:2014_ethz_mmm:bs oschuett
@@ Line 9: / Line 9: @@
    $ module load espresso/5.0.2_openmpi
-. Create a new directory and copy all the files from /cluster/home03/stud/pshinde/Graphene/   to the newly created directory.
+. Create a new directory and download all the **commented** files from the media manager: {{:exercise:exercise_11.2.tar.gz|}}, copying them to the newly created directory.
 **Self-Consistent Field (SCF) calculation:**
@@ Line 44: / Line 44: @@
 . Copy the mol.save directory to scf-mol.save. The scf-mol.save is required for 'bands' calculation
    $ cp -rf mol.save/ scf-mol.save/
-. For density of states calculation, we need dense k-grid. Therefore, do the non-self-consistent calculation using the input file "nscf.in" (Please do not change the k-grid in nscf.in)
+**Non-Self-Consistent Field (NSCF) calculation:**
+In non-self-consistent calculation, the potential is constructed from some “input” charge density and remains fixed. Calculation of DOS can be done in two ways:
+a)	For finite geometries (e.g. molecules), where a single k-point (centre of BZ) is sufficient, the simple way is to perform self-consistent calculation and then DOS calculation.
+b)	For periodic geometries, a high quality DOS might require very fine meshes and for large cells one might need many k-points (depending on the system). Therefore, to save the computational time it is a good idea to calculate the self-consistent charge density with few k-points and then non-self-consistent calculation using fixed self-consistent charge density.
+. For density of states calculation, do the non-self-consistent calculation using the input file "nscf.in" (change the k-grid KX KY KZ) and prefix = './mol'.
    $ bsub -n 4 " mpirun pw.x < nscf.in > NSCF.out "