Fig. 4: Assessing the crystal environment effects on the electronic excited state properties.
From: The carbonyl-lock mechanism underlying non-aromatic fluorescence in biological matter
The QM region for L-gln A and L-pyro-amm G systems are depicted in balls and sticks, and the MM region is depicted in a stick representation. The white, orange, green and blue coloring represent the 3D positions of hydrogen, carbon, nitrogen, and oxygen respectively. Panels B, D, E and H, J, K compare the relevant relaxation degrees of freedom, between the isolated dimer models (black lines) and the QM/MM models of the crystals (orange lines). Panels A to F correspond to the L-glu and panels G to M correspond to L-pyro-amm. Panels B and H correspond to the CO distance degree of freedom, panels D and J to the proton transfer coordinate, and panels E, K to the amide deplanarization mode. Panels C, F, I and L show the QM/MM excited state (orange lines) as well as the Conical Intersection (CoIn, green lines) distributions of the CO distance (C, I) and proton transfer coordinate values F, L, defined as dO-H − dO'-H (where O and O' identify the two carboxyl oxygens involved in the HB).
