Isotherms oxidation-reduction cycle

The isothermal models can be divided into elementary-step models wherein interaction of the elementary steps (adsorption, desorption, and reaction) can produce oscillations without additional mechanisms, and models with additional, non-Langmuir-Hinshelwood steps, such as phase transitions and oxidation-reduction cycles. The latter models are usually supported by experimental evidence obtained by the methods discussed in Section III. 

The electrochemical behavior of the C70 solvent-cast films was similar to that of the C60 films, in that four reduction waves were observed, but some significant differences were also evident. The peak splitting for the first reduction/oxidation cycle was larger, and only abont 25% of the C70 was rednced on the first cycle. The prolate spheroidal shape of C70 is manifested in the II-A isotherm of C70 monolayers. Two transitions were observed that gave limiting radii consistent with a transition upon compression from a state with the long molecnlar axes parallel to the water snrface to a state with the long molecnlar axes per-pendicnlar to the water surface. 

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