prior study provides valuable detail on how backward photoisomerization affects the steady state rotation rate, but without resolving the metastable form into substates. chain systems". The parameter assignment program used in this study, Antechamber, would assign cc to all motors considered here. This may be appropriate for Motor O, with its planar stator, but the ring to which carbon 14 belongs is not conjugated for motors S and N, so type ce seems more appropriate for these two molecules. Indeed, for Motor S and Motor N, using type ce yielded a slightly better value of the objective function in the force field optimization procedures discussed above. In addition, the THI rate constants we computed using ce were generally better than those computed with type cc. Therefore we used ce for motors S and N, with their non-planar stators, and cc for Motor O, with its planar stator. This document provides additional data and details settings of the calculations mentioned in the main text. To reproduce or adapt these calculations, see Github repository github.com/fengmudong/motorpaper, where all the input files and associated instructions can be found.