Electronic Excitations in (BEDT‐TTF)‐Salts

Abstract

AbstractThe indicatrix orientation, the birefringence, and the transmission spectra were measured in small crystals of the organic conductors α‐(BEDT‐TTF)2I3 and α‐(BEDT‐TTF)3(NO3)2 in the near infrared (NIR) and the visible (VIS) spectral range. The results are discussed with regard to the orientation of the BEDT‐TTF molecule axes and the arrangement of the intermolecular contact directions. — The principal polarizabilities are calculated by composing the polarizabilities along the BEDT‐TTF molecule axes and along the several contact directions. At high energies (Δ2 eV) in the VIS the orientation of the polarizability tensor is governed by the orientation of the stack forming molecules due to the intramolecular excitations. In the NIR the intermolecular excitations become dominant. — The transmission spectra are compared with calculations of the dipole interactions.