Anisotropic electron-phonon coupling in alpha '-NaV2O5

We have explored the complete first-order, room-temperature Raman tensor of alpha'-NaV2O5. Fano line shapes and electronic continuum bands appear only in A(g)(a), B-2g symmetry. This indicates strong electron-phonon coupling in the plane perpendicular to the ladder axis and along the ladder rung. Re duction of the Na concentration with respect to stochiometric alpha'-NaV2O5 has a strong influence on the observed electronic continuum bands while in crease of the Na content has little effect on the spectra. We employ lattic e-dynamical calculations to determine the main characteristics of the obser ved vibrational modes and discuss the possible relation of the observed bro ad continuum bands to dynamic polaronic deformations along the ladder rung and magnetic coupling of the delocalized intercalated charge.