Theory of the Self-Trapped Hole in the Alkali Halides

The lattice relaxation energy associated with self-trapping of a positive hole and an exciton in alkali halides

“…Rough estimates, following [18] and [20], suggest Dh cannot be negligible unless the [V,e] model holds. In all, therefore, the large value of D, of [12] leads to an apparent inconsistency unless the degree of off-centring, if any, is small.…”

Optical behaviour ofH-type centres produced by KrCl excimer laser excitation of KI and KI: Na crystals

“…This fact implies that the excited 'Cg' states of Hand HA(Na) in KI, of which each centre involves an interstitial iodine atom, mix considerably with the 5p valence electron states of iodine ions neighbouring to 1; in these centres. Namely, as suggested by Jette et al [7], such a mixing causes Hall-orbitals to spread out onto the halogen ions, and results in lowering the energy level of the 'Cg' state. Now, the absorption intensity of both the H(557)-and H~ ( 5 8 0 ) bands due to 'C: -+ 211g1/2 allowed for 7r-polarised light is significantly strong ( Table I).…”

Structure of the self-trapped hole in the NaCl crystal: An ab initio periodic HF/DFT study

“…In this model, the ground electronic state of a hole 2 S u is located as an antibonding molecular orbital s u . Optically, centers of the X 2 À type are usually characterized by the presence of two clear-cut absorption bands, one of which is in the UV range and corresponds to the s g -s u transition (in the notation of the electron transfer), while the other is referred to the near-IR range and corresponds to the p gs u transition [1,2]. The molecular model provides a correct description of the EPR properties of V K centers, effects of the crystalline field, and the spin-orbital interaction [3].…”