The potential energy surfaces are obtained on the fly
using a semiempirical reparameterized AM1 Hamiltonian, with the FOMO-CI
approach. A serious effort is made by the author to validate the
semiempirical data (energies and optimized geometries) with respect to
ab initio and experimental values, so that the reader may have an idea
of the accuracy of the results.
The nonadiabatic molecular dynamics results are compared with that of
the parent compound brAB; interestingly, the authors found that the
increasing steric effect from Z-ID to Z-DIDmeso to Z-DIDrac, plays a
similar (but reversed) role with respect to solvent in brAB.
I only have some minor remark:
1) Why, for the dynamics starting from the E isomers, the early surface hops to S0 and the subsequent revival are claimed to be an artifact of the surface hopping approach, in particular connected with quantum decoherence effects? In fact, as the early hops to S0 and the backward ones happen really early (within the first ~20 fs), the quantum decoherence should play very little or no role. This behavior was also noted in the parent compound brAB, and attributed to the presence of a plateau in the S0 PES: if this is the case for ID
and DID too, then the revival in the S1 population is due to a single
passage through an extended strong interaction region (rater than to a
recrossing of a localized strong interaction region) and then, again,
the decoherence should play no role.
2) The semiempirical S0->S1 transition energies for the E isomers appear
to be too low. While I do agree with the authors that this most probably
do not change the qualitative pattern of the dynamics, something can be
said on the influence that this may have from the quantitative point of
view. In particular, both the S1 lifetime of the E isomers and the E->Z
photoisomerization quantum yields are probably underestimated.
3) It would be of help to the reader if the authors could add PES cuts
along the CNNC coordinate for the S1 and S0 states of the three isomers.