Femtosecond Electron Delocalization in Poly(thiophene) Probed by Resonant Auger Spectroscopy

Abstract

Ultrafast electron dynamics in the low-femtosecond regime was evaluated for poly(thiophene) by resonant Auger spectroscopy using the core-hole clock method. Sulfur KL2,3L2,3 Auger decay spectra were measured as a function of the photon energy. Remarkable changes developed by tuning the photon energy along the sulfur 1s absorption edge, depending on the nature of the intermediate core excited states. Features characteristics of the Auger Resonant Raman effect were observed. Competition between core hole decay and delocalization of the photoexcited electron was monitored. Branching ratios of Raman (spectator) and normal Auger channels were calculated and electron delocalization times derived.