Dear All

I'm doing MD simulation of solution interactions with a mineral surface. I studied the tutorial "polymer interactions with a metal oxide surface", because I thought what I was doing was similar to the tutorial, the solution confined layer was built with Amorphous Cell,  and the mineral layer Ca5Si6O16(OH)2 is kind of a metal oxide. Can I perform my simultion like what the tutorial does? And I have another question, in the tutorial, after the geometry optimization of the metal oxide, all the aluminum oxide atoms are constrained during the molecular dynamics, actually, I read in some other papers, the solid phase was freezed either in two or three directions while interacting with aqueous phase, what's the reason to do that?

Thank you.

Jingjing Bu