Identification of I3 − and I5 − clusters in irradiated ki by X-ray photoelectron, Raman and optical absorption spectroscopies

Raman and XPS measurements have been performed on KI crystals irradiated near 200 K. The Raman studies show I3 − and In − (n = 5, 7,—) clusters which anneal together with F- and V- centres at 338 K. A small development of (I2)n aggregates occurs during the anneal; these decay near 378 K and are responsible for a broad and weak residual V-band. The I 3d 5/2 XPS peak has been fitted to reveal the presence of 3 components after low energy argon- ion bombardment. These are identified as due to normal lattice iodine, I3 − and 15 − whose behaviour is consistent with the Raman work.