1. Infrared and Raman Study of the Charge-ordered State of θ-(ET)2Cu2CN[N(CN)2]2
- Author
-
Yasuhiro Shimizu, Kyuya Yakushi, Takashi Yamamoto, and Gunzi Saito
- Subjects
Materials science ,Infrared ,General Physics and Astronomy ,Infrared spectroscopy ,Charge (physics) ,Dihedral angle ,Molecular physics ,Charge ordering ,symbols.namesake ,chemistry.chemical_compound ,Nuclear magnetic resonance ,chemistry ,Molecular vibration ,symbols ,Raman spectroscopy ,Tetrathiafulvalene - Abstract
The polarized Raman and infrared spectra of θ-(ET) 2 Cu 2 CN[N(CN) 2 ] 2 [ET = bis(ethylenedithio)tetrathiafulvalene] were measured at various temperatures below 300 K. We investigated the three C=C stretching modes, v 2 , v 3 and v 27 . The spectral pattern is compatible with the horizontally charge-ordered state, where the site-charge distributions are +0.1 7 and +0.8 3 . We have found that the vibronic v 3 bands correlate to the dihedral angles, ϕ, in the θ-ET salts. This relation is well reproduced by the numerical calculation based on the cluster model with C 2 symmetry. The spectral features suggest the dynamical fluctuation of nearly localized charges even above its phase transition temperature, ∼220 K.
- Published
- 2004