| Popis: |
We have performed a Raman spectroscopic investigation on 13 C enriched BEDT-TTF molecules which has been motivated by isotope shift experiments of the superconducting transition in the s H phase of (BEDT-TTF) 2 I 3 (T c ≈ 8.2K at mid transition) stabilized at low temperature via the adequate cooling procedure. In the C=C stretching region, two main bands are observed at 1521 and 1468 cm −1 , shifted downward compared to the 1555 and 1495 cm −1 in 12 C BEDT-TTF, and simple calculations predict very well this shift. Also, these bands are recorded with different intensities. In the Raman spectrum, the 1512 cm −1 mode, assigned to a combination mode, presumbly appears much weaker at 1485 cm −1 . |
