I am trying to perform a geometry optimization (GEO_OPT) of a FCC 111 Pt_{0.5}Au_{0.5} bimetallic surface (10x10x3) generated from ASE, with a lattice parameter of 3.9 A∘A∘ in CP2K. However, after the geometry optimization is completed, the visualization of the coordinates show that the top layer gold atoms are moving away from the surface layer.
I am using CUTOFF 400 and REL_CUTOFF 60 for the calculations. I am unable to figure out how to resolve the problem. I think the forces are very high. I am trying a cell optimization calculation.
Will this be useful? Or should I change something else in the geometry optimization calculations?
Any help will be much appreciated. Thanks in advance.
Are you running a periodic calculation or a non-periodic calculation? It seems that you have generated a surface, then have you specified a vacuum of at least 10-15 Angstrom in the x or y or z direction to avoid the spurious interaction with its periodic image?
Arup Sarkar I am running a periodic calculation in the xy direction, z direction being the vacuum to avoid periodic image interaction