The phonon dynamics of ${\mathrm{LiV}}_2{\mathrm{O}}_5$ single crystals is studied using infrared and Raman spectroscopy techniques. The infrared-active phonon frequencies and dielectric constants are obtained by oscillator fitting procedure of the reflectivity data measured at room temperature. The Raman-scattering spectra are measured at room temperature and at $T=10\mathrm{}\mathrm{K}$ in all nonequivalent polarized configurations. The assignment of the phonons is done by comparing the infrared and Raman spectra of ${\mathrm{LiV}}_2{\mathrm{O}}_5$ and ${\mathrm{NaV}}_2{\mathrm{O}}_5.$ The factor-group analysis of the ${\mathrm{LiV}}_2{\mathrm{O}}_5$ crystal symmetry and of its constituent layers is performed to explain the symmetry properties of the observed modes. We concluded that layer symmetry dominates in the vibrational properties of this compound.

• Received 5 May 1999

DOI:https://doi.org/10.1103/PhysRevB.61.11454