Raman spectrum of U4O9: a new interpretation of damage lines in UO2

Characterisation of uranium oxides in different conditions is a challenge both in nuclear and environment sciences. We focus here on U₄O₉, which is a superstructure of UO₂. Homogeneous U₄O₉ powder was fabricated and characterised by Raman spectroscopy. The Raman spectrum of a pure‐phase U₄O₉ is, for the first time, completely described and interpreted. U₄O₉ Raman spectrum derives from the well characterised one of UO₂. Besides reminiscent modes of UO₂, a band at 630 cm^‐1, which has a specific response to polarised light, was interpreted as characteristic of clusters of interstitial oxygen atoms. These experimental data will help to rationalise the interpretation of UO₂ damaged samples. Copyright © 2011 John Wiley & Sons, Ltd.