[Mushiness5623]

I am trying to model an adsorbing process (or more precisely, Heterogeneous catalysis process between solid catalyst and gas reactants). My approach is to minimize the Hamiltonian by optimizing the coordinates of the adsorbent and adsorbate.

To minimize the needs of computing, I define an active space by selecting the electrons and orbitals.

My question is do I need to taking into account of the active electrons / orbitals of the catalyst?