Simple (?) optimization question

[narin]

Dear users,

I'm a newcomer to ATK and trying to optimize an arsenene structure in ATK-VNL. I placed an Optimize Geometry block and let the default values as shown in the attached figure 1. Then, I run the simulation without any errors. I checked the resulting geometry (trajectory) as shown in attached figure 2 but the optimization did not change the z-positions of (so called buckling) of atoms. What can I do to geometrically optimze this structure so that I can see the buckling after optimization?

Thanks a lot.
Narin :

[mlee]

You used the fixed lattice constant of x,y and z in the OptimizeGeometry. If you want to relax it in all axes, untick them not to fix the lattice constant.