8-12 July 2013
Africa/Johannesburg timezone
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Analysis of electron diffraction patterns in DCNQI salts

Presented by Mr. Olufemi Opeyemi OLAOYE on 9 Jul 2013 from 17:40 to 18:40
Type: Poster Presentation
Session: Poster1
Track: Track C - Photonics


We investigate a donor-acceptor quasi 1D organic molecular crystal, Cu [R1, R2 – DCNQI]2 (R1 and R2 are radicals), using ultrafast electron diffraction technique. These crystals are radical anion salts and are famous for their high anisotropic electric conductivities and their low temperature Peierl’s transition from metal to insulator, with up to eight orders of magnitude conductivity change, depending on the radical used. The signature of the intensity distribution of the {h0l} Bragg reflections along the [010] Laue zone is analysed and compared with the theoretical simulation. The formation and dynamics of 3-fold periodicity charge density wave (CDW) in these crystals, which are mediated by d-p-π hybridization and the coordination angle α (N-Cu-N angle), forms an on-going research in our laboratory. The ultimate aim of the project is to study the photo-induced Peierl’s transition with sub-picosecond temporal resolution by means of ultrafast electron diffraction. The poster will present the theoretical background of the project, and highlight the subtle and difficult analysis of our transient diffraction patterns.






HEINRICH SCHWOERER, heso@sun.ac.za, Stellenbosch University