[QE-users] gamma points calculation

[Giuseppe Mattioli]

You should use gamma-only (which is less greedy for memory and faster  
than any other option) when

1) your system isn't really periodic and does not show bandlike  
dispersion in k (e.g., an isolated molecule or a cluster in a large  
periodic box).

2) your system is not a unit cell and it is so large that the band  
structure in the (tiny) Brillouin zone is practically all refolded  
into gamma. In this case you should usually check the convergence of  
total energy/forces with respect to k points to stay on the safe side.

HTH
Giuseppe

Quoting naval singh via users <users at lists.quantum-espresso.org>:

> Dear all,i have been using quantum espresso for some time and using  
> k points i came across a paper where a researcher used gamma points  
> calculation owing to the size of the cell, i wanted to know when  
> should one use the gamma k points caclculations 



GIUSEPPE MATTIOLI
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