Dear ZhengPing,
On Wed, Oct 21, 2009 at 3:12 AM, ZhengPing Fu <[email protected]> wrote: > Hi, > I have a similar problem with siesta2.02 and siesta3.0b > I can relax the coords with siesta2.20 successfully, while I failed with > siesta3.0b for the same > input file because the scf calculating diverged from some CG step on. > I didn't find any notable difference between the geometry structure that got > converged scf calculating > and that got diverged scf calculating. The algorithm for extrapolation of the DM accross geometries has changed in Siesta3.0-b. The divergences you are seeing might be related to an inadequate extrapolation for a big geometry change. You might want to tune the behavior by either: - Disabling DM extrapolation, or even the reuse of the DM accross geometry steps. - Specifying a maximum step size for the CG algorithm - Switching to another relaxation algorithm such as quenched MD, or the similar FIRE algorithm. You can find the relevant FDF options in the manual. Regards, Alberto
