Hello, All,
Here is a script that will compute charge density differences with DMol3. It is currently limited to PERIODIC CASES only.

You define a set of atoms called "Sorbate". The script will then compute the charge density on the total system, then on set "Sorbate" and then on the remaining atoms.

Finally, it computes the density difference of system - components and writes them to a new field. It displays this charge density difference field in a new document