RAMAN SCATTERING OF \alpha-ET₃(ReO₄)₂ CHARGE-TRANSFER SALT

We describe the results of Haman studies on C=C stretch modes in \alpha-ET₃(ReO₄)₂ charge-transfer salt with the incident laser beam polarised perpendicular and parallel to the large flat face of plate-like crystal. We have assigned central C=C stretch mode at 1454 cm^-1 and ring C=C stretch mode at 1470cm^-1. The change in ring C=C stretch vibration was observed at the metal-insulator transition of \alpha-ET₃(ReO₄)₂ on warming due to the distortion of the ET molecules.