Vibrational spectra and electrostatic fields of V2O5 and lithium vanadium bronzes

Vibrational spectra (IR absorption and Raman) of vanadium oxide, V2O5 and lithium vanadium bronzes (Li0.04V2O5 and Li0.35V2O5), including those Li-6 substituted have been studied. Results of the theoretical analysis of the vibrational spectra of these compounds and calculations of the electric field in a selected positions of the crystal lattice are presented. Values of electrostatic potential in the positions of the lithium cations are lower in case of Li0.04V2O5 structure then in Li0.35V2O5. Maximum amplitudes of vibrations of the lithium cations are found to be in the 010 crystallographic direction for both compounds. Theoretical calculations of the electrostatic field in the vicinity of positions of lithium cations show that it vector has the smallest component in the same crystallographic direction (010) making possible easy migration of lithium cations. (C) 1997 Elsevier Science B.V.