Alexander A. Granovsky

TL;DR: The efficient implementation strategy that makes XMCQDPT2 an especially useful general-purpose tool in the high-level modeling of small to large molecular systems is described.

TL;DR: It is found that standard time-dependent DFT (TDDFT) does not yield the correct two-dimensional crossing along the branching plane but rather a one-dimensional Crossing along the same plane, and that for the same initial conditions, the two methods yield similar dynamics leading to isomerization quantum yields that differ by a few percent.

TL;DR: It is shown that introducing the missing dynamic electron correlation variationally and perturbatively leads to a stabilization of the regions with charge transfer character and to a significant reshaping of the reference CASSCF potential energy surface and suggesting a change in the dominating isomerization mechanism.

TL;DR: The photoisomerization of azobenzene in solution shows no viscosity dependence, putting into question the torsion mechanism and suggesting the hula-twist isomerization mechanism.

TL;DR: The penta-2,4-dieniminium (PSB3) cation is employed as a minimal model of the retinal chromophore of visual pigments and its excited state isomerization paths are compared at the CASSCF and CASPT2 levels of theory to provide benchmark values against which other ab initio methods are validated.