Fig. 4: Effects of the molecular system size on the dynamics of the C=O bond potential energy at constant solute concentration.

The Rabi splitting and molecular number density have been fixed. Black lines correspond to the data in Fig. 3b (N_sub = 216), and the lines from dark red to orange represent increasing molecular systems where N_sub is increased by a factor of N (N = 2, 4, 8, 16). In all cases, we excite the LP and measure the amount of potential energy in the C=O bonds. Note that the selective polaritonic energy transfer to the ¹³CO₂ solute molecules is fairly robust against molecular system size, indicating that the current finding may hold for collective VSC with large cavity volumes but under the same Rabi splitting, i.e., smaller \(\widetilde{\varepsilon }\); see text below and also Supplementary Fig. 1 for an explanation of the system size dependence.