Dear users,

I am working on computational studies involving the adsorption of organic molecules on metal surfaces (such as iron and zinc). I am using Materials Studio with the DMol3 module for my calculations.

As I am still at the beginner stage in this field, I would greatly appreciate your guidance regarding the appropriate selection of the k-point mesh for my system. Specifically, I am working with a surface model of size 8×8 consisting of five atomic layers, and I would like to ensure that my calculations are both accurate and computationally efficient.

Could you kindly advise me on how to choose a suitable k-point grid for such a system? Additionally, I would be grateful for any recommendations or best practices you might suggest for achieving reliable adsorption results using DMol3.

I would also like to ask whether it is necessary to perform geometry optimization for the unit cell before constructing the surface model. If so, what k-point mesh would you recommend for the unit cell optimization step?

Edited 

When performing optimization, is there a single k-point for both the unit cell and the surface? If I want to compare more than one surface, for example, Fe (0, 1, 1) and Zn (0, 0, 2), should the k-point mesh be constant? And how should it be chosen? What are the steps of convergence test?