For the volcano curve system depicted in Fig. with amplitude of 0.6 eV square waveform, the instantaneous TOF B is depicted in Figure An interpretation of catalytic surface resonance comes from evaluating the TOF B response of each condition independently, as shown in Fig. . The rate of production for surface species B* is defined by the forward surface reaction rate constant and surface coverage of A* (which is in equilibrium with gas phase A). Similarly, the rate of desorbing B* to gas product B is defined by the desorption rate constant and surface coverage of B*. In this case, the time scales of these two processes sum to the total time scale, which is comparable to the applied square waveform time scale at resonance. This concept is visually observed in Fig. , where TOF B for the two purple points predict 60 s -1 for each independent process, while the actual TOF B predicted by simulation is exactly half of that value, 29 s -1 (Fig. and). To put it simply, catalytic surface resonance occurs when the frequency of the applied surface state-switching waveform matches the natural frequency of the catalytic kinetics.