The ∆PDF signature at 260 fs after photoexcitation of αPh is compared in Fig. with simulated product ∆PDFs analogous to Fig. . There are strong deviations between all the simulations and the experimental signature between 1 Å and 2.5 Å, which can be related to the approximation of the photoproduct by a single, vibrationally cold geometry. A much better agreement in this area can be reached by explicitly simulating the molecular dynamics leading to the photoproduct (see Fig. ). However, all curves in Fig. qualitatively agree on negative signatures at 1.4 Å and 2.4 Å, which can be, analogous to the CHD ring-opening signatures, assigned to an increase in the R1 and R2 distances (as defined in Fig. ). Above 2.5 Å, the experimental ∆PDF agrees well with the simulated signature of the photochemically allowed electrocyclic ring-opening product of the quasi-equatorial conformer of αPh, (3Z,5E)-3,7dimethylocta-1,3,5-triene (ZEDOT), with a strong positive signature at 3.5 Å, and weaker positive and negative signatures above 3 Å. The signature at 3.5 Å has contributions from the R1 and R2 distances in the photoproduct as well as from the dissolution of the bimodal distribution in the third carbon coordination sphere. The latter is due to a loss in the rigidity of the molecule both through the ring-opening and the level of vibrational excitation in the photoproduct.