Dear Lily, the cutoff energy giverns the fineness of the REAL space 3D grid that is used to approximate real space integrals of several quantities and for representation of charge density and potentials etc. At the other hand, the k-grid is used for discrete integration in RECIPROCAL space.
The two grids are unrelated, so there is no direct correlation between the value of Ecut and the density of the Monkhorst matrix. You will have to do convergency tests for both parameters. Best wishes Roland On 7 July 2011 20:33, lily zheng <[email protected]> wrote: > Dear all Siesta user, > > > I got one stupid question about energy cutoff and kgrid monkhorst pack. Is > there any correlation between them? for instance, if value of Ecut given, > we could estimate k-grid monkhorst matrix? > > > thanks > > Lily >
