How Dispersion Interactions at the Excited State Can Tune Photochromism of Embedded Chromophores.

ABSTRACT: We present QM/MMPol-cLR³, a polarizable embedding quantum mechanics/molecular mechanics (QM/MM) framework that includes explicit, state-specific dispersion terms. This method enables a rigorous treatment of dispersion on top of electrostatic and induction effects in ground- and excited-state calculations. Using QM/MMPol-cLR³, we show that dispersion interactions control excited-state solvatochromism through two distinct mechanisms. In azulene, opposite shifts of the L_a and L_b states arise from state-specific dispersion linked to changes in excited-state polarizability. In bacteriochlorophyll a, dispersion instead stems from the interplay between polarizability changes and transition-dipole-driven response, governing the Q_y

SUBMITTER: Guido CA 

PROVIDER: S-EPMC12814335 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature