Charge-ordering and optical transitions of LiV2O5 and NaV2O5
  We present the measurements of the polarized optical spectra of NaV2O5 and LiV2O5. In an energy range from 0.5 to 5.5 eV we observe similar peaks in the E parallel a spectra of LiV2O5 and NaV2O5, which suggests similar electronic structure along the a axis in both materials. On the other hand, we find an almost complete suppression of the peaks in sigma_b of LiV2O5 around 1 and 5 eV. We attribute this suppression to the charge localization originating from the existence of double-chain charge-ordering patterin in LiV2O5. 
M.J.Konstantinovic, J.Dong, M.E.Ziaei, B.P.Clayman, J.C.Irwin,   K.Yakushi, M.Isobe and Y.Ueda