Ref. 438 investigates how collectively coupling an ensemble of Mg atoms to cavity radiation can modify chemical reactivity in a molecule (MgH + ) also coupled to cavity radiation (as schematically shown in Fig. ). Two relevant molecular electronic states and two atomic electronic states are considered in this work. The work assumes a Tavis-Cummings Hamiltonian and focuses on the single excited subspace spanning either a molecular or an atomic excitation or 1 photon in the cavity.