RAMAN-SCATTERING OF ORGANIC CHARGE-TRANSFER SALTS CONTAINING BEDT-TTFCATION

Raman scattering of several organic charge-transfer salts containing B EDT-TTF of ET cation such as kappa-ET(2)Cu(NCS)(2), beta(L)-ET(2)I(3), alpha-ET(3)Cl(2). 2H(2)O, alpha-ET(3) (ReO4)2 and ETFeBr(4) were meas ured and the variations of the frequencies of C=C bonds of ET molecule s on charge transfer were observed. It is found that the energy of C=C stretch modes shows a general downward shift upon ionisation of ET mo lecule. In addition, we have observed the Raman spectra of C=C stretch vibrations in kappa-ET(2)Cu(NCS)(2) single crystal on going through T -c (similar to 10.4 K) and found no detectable effect during the super conducting phase transition.