Can USPEX do global optimization for adsorption of some atoms onto a fixed slab surface?

[Dragon Don]

Dear experts,

  I know USPEX is very efficient for crystal structure prediction, I am wondering if USPEX can search for the best adsorption structure for some atoms' adsorption onto a fixed slab, that is, only a few atoms' positions are free during the evolution, while the slab atoms are barely fixed. Is that possible to conduct via USPEX, and what should I do ?

 Looking forward to your response, many thanks in advance~

best wishes,

Dragon Don