Proton transfer in DNA

Hello! I’m currently utilizing QChem and the NEO-DFT method to investigate quantum proton tunneling effects in a small system. My approach involves comparing the energy barriers obtained through traditional DFT and NEO-DFT with activated proton tunneling. While I’m able to obtain the energy barrier results, I’m uncertain about how to distinguish the tunneling contributions from the zero-point energy effects. Additionally, could you explain why a decreased barrier in the potential energy surface (PEF) is indicative of significant nuclear effects?