MeshCutoff controls the number of points in 3D grid to represent, say, the charge density of your system. The bigger the MeshCutoff the more points you have and calculation is closer to "converged".
EnergyShift controls the localisation of your basis functions. In Siesta basis functions are strictly zero beyond some radius. Since we confine wavefunction within this radius, we make some small energy shift upwards (remember, that according to variational principle the true wavefuction has lowest energy). So the EnergyShift parameter is just the way to control confinement radius. Ruslan Zhachuk 2010/3/8 Guangping Zhang <[email protected]> > Hi, > Can anyone explain me PAO.EnergyShift and MeshCutoff in detail? I have > turned to many stuffs.But now I yet can not understand it clearly! > > THANKS IN ADVANCE ! >
