Руслан Жачук a écrit :
Dear SIESTA users,
could you please explain me the sense of MeshCutoff parameter in SIESTA?
The manual is short in this respect:
-------------
MeshCutoff: Defines the equivalent plane wave cutoff for the grid.
Default value: 100 Ry
-------------
I can understand energy cutoff parameter in plane-wave based codes
like VASP,
it just controls the number of plane waves used to render wavefunctions.
Thus, in VASP it actually controls the accuracy of calculation.
But SIESTA is based on atomic orbitals.
So what this parameter actually does in SIESTA?
Should the calculation be converged relative to this parameter?
Any recommendations?
Kind regards
Ruslan
Ruslan,
100 Ry is usally a minimum: try 150, 200, 250 Ry for seeing how your
total energy converges.
You can also use the grid cellsampling trick (read the documentation) to
save computation time.
This parameter has nothing to do with plane waves, but I can imagine it
makes sense
to convert the fineness of a grid in real space into a cutoff energy
when you come from the dft/pw
community.
Bye,
Phil
