3.9 Efficiency of Dynamic Catalysis at Oscillatory Steady State. Returning to the concept of imparting work during catalysis as described in Figure , the observed free energy change for the reaction (ΔΔG) is related to the applied oscillation amplitude (ΔU i ). In mechanical applications, this relationship is typically expressed as an efficiency, which compares the applied work (i.e. energy units after integrating over time) to the resulting change in system enthalpy, internal energy, or another indicator such as temperature. Here, the efficiency of the dynamic catalytic system is defined as,