Probing ultrafast ππ*/nπ* internal conversion in organic chromophores via K-edge resonant absorption.

ABSTRACT: Many photoinduced processes including photosynthesis and human vision happen in organic molecules and involve coupled femtosecond dynamics of nuclei and electrons. Organic molecules with heteroatoms often possess an important excited-state relaxation channel from an optically allowed ππ* to a dark nπ* state. The ππ*/nπ* internal conversion is difficult to investigate, as most spectroscopic methods are not exclusively sensitive to changes in the excited-state electronic structure. Here, we report achieving the required sensitivity by exploiting the element and site specificity of near-edge soft X-ray absorption spectroscopy. As a hole forms in the n orbital during ππ*/nπ* internal conversion, the absorption spectrum at the heteroatom K-edge exhibits an additional resonance. We demonstrate t

SUBMITTER: Wolf TJA 

PROVIDER: S-EPMC5481431 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature