Excited-state geometries coordination compounds

SCHMIDTKE Excited State Geometries of Coordination Compounds... 

This example illustrates the complexity of the excited states dynamics in this class of molecules. The early stage dynamical behaviour (in the first ps) may be tailored by the metal centre, the a-diimine group or the surrounding ligands. These chemical factors govern the character and electronic localization of the excited states, their relative position, the presence of critical geometries. Moreover the shape and relative positions of the PES may be also modified by the other experimental conditions like solvent effects. Obviously the development of new theoretical tools able to compute accurate multidimensional PES is needed to investigate the dynamics of photochemical reactions in transition metal coordination compounds. 

Figure 3.1 Schematic representation of photochemical reaction involving a conical intersection. The X axis corresponds toXs the "reaction path," which is a representative coordinate orthogonal to the branching space Xi X2. The Y axis (X1/2) is a compound coordinate, corresponding to a vector that lies in the plane spanned by X, X2. Photoexcitation from the ground-state geometry, GSi, leads to the excited-state potential energy surface at point EXq. The excited-state branch of the reaction coordinate continues to various points on the conical-intersection seam Cl, and CI2. At this point decay occurs in the branching space Xi X2 at the double cone shown inset and the reaction path continues on the ground state toward possible products GSt and GS2. Adapted from Serrano-Perez et al. ...

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