The key result of this calculation is the impact of the isomerization on the excitation energy of the cycling transition, X → A. Although this value can be affected by a change of the ligand, the computed excitation energy change due to the isomerization is minute (on the order of 1 meV). Thus, pAB results show that AB acts, to a large extent, as an inert scaffold, carrying the OCC in space without impacting the characteristics of the cycling transition. This can be rationalized by the observation that in the gas-phase, the OCC does not experience large variations in its environment between the trans-and cis-isomers.