Raman, infrared and optical spectra of the spin-Peierls compound NaV2O5

We have measured polarized spectra of Raman scattering, infrared and optical transmission of NaV2O5 single crystals above the temperature of the spin-Peierls transition T-SP = 35 K. Some of the far-infrared (FIR) phonon lines are strongly asymmetric, due to the spin-phonon interaction. In addition to the phonon lines, a broad band was observed in the c(aa)(c) over bar Raman spectrum and in the Ella FIR transmission spectrum. A possible origin of these bands is discussed. The absorption band at 10000 cm(-1) (1.25eV) is attributed to vanadium d-d electronic transitions while the absorption edge above 3eV is supposed to correspond to the onset of charge-transfer transitions.