Vibronic coupling, symmetry and dynamics in unsaturated hydrocarbons

[摘要] This theoretical work looks at excited state photochemistry - the study of the molecular processes triggered by the absorption/e mission of light to/from electronically excited states. The approach taken here is that of using approximate vibronic coupling models, as well as extending the methods and algorithms to construct them. These are then used in quantum dynamic calculations to obtain time-dependent properties, compute spectra and calculate dissociation cross-sections. A genetic algorithm which aids to the fitting of diabatic model parameters is described in detail and tested in two systems. The neutral and cationic surfaces of cyclo-butadiene is one of the systems for which this fitting algorithm was used and the photo-electron spectrum was then calculated to compare with the experimental one. We show how one can generate polynomial functions which are invariant with respect to the non-Abelian point groups. These invariant polynomials are then used for the construction of an acetylene model, where photo-dissociation cross sections are calculated for all possible angles. A bigger system Tolan, the monomial of a family of a photo-active dendritic antenna, was modelled. Comparison between the experimental and calculated absorption spectra validates the model and is subsequently used to model the first few picoseconds of population transfer.

[发布机构] University:University of Birmingham;Department:School of Chemistry

[关键词] Q Science;QD Chemistry