The electronic structures and absorption spectra of the perfect CsI crystal and the CsI crystal containing VCs- were calculated using CASTEP code with the lattice structure optimized. The calculated results indicated that the optical symmetry of CsI crystal concided with the lattice structure geometry of CsI crystal. The perfect CsI crystal had no absorption band in the visible region. However, the absorption spectra of the CsI crystal containing VCs- exhibited two peaks at 2.21 and 3.00eV in the visible and near-ultraviolet region, which were caused by VCs-.

Study on the Absorption Spectra and Electronic Structures of the CsI Crystal with Cesium Vacancy. X.Ying, Z.Ni: Computational Materials Science, 2010, 48[3], 658-61