If so, that's too restrictive. The interaction between two He atoms needs QM (dispersion forces). Heck, even two water molecules interacting is a QM even if you decide to classify the polar attraction as purely classical. You'd still be omitting a lot of the interaction energy.
I see no way I can simulate catalyzed (enzyme) breaking of a chemical bond without:
If so, that's too restrictive. The interaction between two He atoms needs QM (dispersion forces). Heck, even two water molecules interacting is a QM even if you decide to classify the polar attraction as purely classical. You'd still be omitting a lot of the interaction energy.
I see no way I can simulate catalyzed (enzyme) breaking of a chemical bond without:
1. Direct or indirect use of at least DFT
2. An empirical solution (curve fitting to data)