Geometry Optimisation with CASTEP
Geometry Optimisation with CASTEP
Geometry Optimisation with CASTEP
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Next: Cell symmetry Up: The .cell file and Previous: The Initial Configuration of<br />
The k-point sampling grid<br />
The points in k-space at which the Brillouin zone is to be sampled can be defined in one of three ways.<br />
As a list<br />
%BLOCK KPOINTS_LIST<br />
units<br />
%BLOCK KPOINTS_LIST<br />
The first three numbers on a line are the co-ordinates of a k-point as fractions of the relevent reciprocal<br />
space lattice vector. The final number is a weight for the k-point. The weights of all n k-points must add<br />
up to 1.<br />
Another way is to use a Monkhurst-Pack grid and there are two ways of doing this.<br />
The first way is to specify the grid dimensions in the three directions of the reciprocal space lattice<br />
vectors<br />
KPOINTS_MP_GRID<br />
So, for example, we could have a 2x2x2 grid or a 3x4x1 grid. The choice depends upon computational<br />
resources and whether a more detailed sampling of the electronic wave function is required in a given<br />
reciprocal space direction.<br />
A second way of requesting a Monkhurst-Pack grid is to specify a minimum grid density.