Pressure-induced structural phase transition inLiV2O4

Extended x-ray absorption fine structure analysis of $\mathrm{Li}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$ at the vanadium $K$ edge under pressure is discussed. Changes in the absorption spectra at room temperature show that a structural phase transition is induced at high pressure. This phase transition can be attributed to a charge ordering, as it was observed in the isostructural compound $\mathrm{Al}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$. The absorption spectra have been analyzed by considering the two models previously proposed for $\mathrm{Al}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$. Our results indicate that the high pressure structure of $\mathrm{Li}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$ is probably implying the formation of ``vanadium molecules'' in a geometrically frustrated crystal.