The of two molecules inside the cavity are identical to each other. In Fig. ) and (c), we present the reactant population dynamics P r (t) = P 1 r (t) = P 2 r (t), and the scaled flux-side correlation function k(t) = k 1 (t) = k 2 (t) (see the definition in Eq. ( )), respectively, for parallel (orange lines) and anti-parallel (green lines) dipole configuration. The cavity frequency is set to ω c = 1200cm -1 and the light-matter coupling is η c = 0.00125 a.u. . For comparison, we also display the results for a single molecule inside the cavity (blue lines). The dipole orientation of two molecules has a strong impact on the transient dynamics. In the time regime t < 2000 fs, we observe that for the parallel homodimer, P r (t) decreases faster, and k(t) is more oscillatory as compared to those of the single molecule inside the cavity. Conversely, the opposite behavior is observed for the anti-parallel homodimer. However, the rate constant k obtained in the long time region when k(t) reaches the plateau is the same for both dipole configurations, which is slightly higher than that for the single molecule, as shown in the inset of Fig. ).