In the excited state, the access to the 47 • CX from the 0 • exhibits a barrier of 8.60 kcal/mol in SF-TDDFT, whereas the 121 • CX features a barrier of 10.50 kcal/mol. These are in good agreement with the MRSF-TDDFT barriers, which are 8.77 kcal/mol and 12.77 kcal/mol for the access to 47 • and 121 • CXs respectively. This indicates that from 0 • to 180 • the rotation along the CX at 47 • is more favorable than the one at 121 • . From the 180 • , the barrier predicted by SF-TDDFTB to access the 121 • CX is 13.31 kcal/mol, whereas the 47 • CX has a barrier of 11.34 kcal/mol. These are similar to the MRSF-TDDFT barriers, which are 17.61 kcal/mol for the barrier to access the 121 • CX, and 8.24 kcal/mol for the barrier to access the 47 • CX. This would indicate that the rotation from 180 • to 0 • is also happening via the 47 • CX, thus indicating a non-unidirectional rotation. Still, these interpolated geometries do not correspond to the optimized S 1 geometries, which could lower down the barrier.