Recent theoretical investigations have suggested that the ground state of a molecular system can be significantly modified by coupling the electronic states of a molecule to a cavity photon mode.. In particular, it has been shown that the cavity can modify the endo/exo selectivity of Diels-Alder reactions, 20,21 modify the ground state proton transfer reactions barriers and driving forces, and selectively control the product of a click reaction. Note that the cavity frequency in these studies is chosen to be in the range of electronic excitations in molecules (in terms of energy, on the order of eV), and thus the resulting polaritonic effects are expected to be different than the more commonly explored VSC regime. In addition, for this case cavity-modified chemistry does not require the usual resonance effects of lightmatter interactions (i.e., frequency matching between light and matter excitations), since the cavity can directly modify the ground state of the hybrid system, referred to as quantum vacuum fluctuation modified chemistry. Importantly, predictions based on single molecules coupled to a cavity are also within the reach of the magnitude of strong coupling shown in recent experiments using a plasmonic nano-cavity. A conceptually understand these recently proposed ground state modifications due to the cavity vacuum fluctuations are provided in the Theoretical Methods section.