Z (Ag ^– ) centres in NaCl: (Ag ⁺ +Ca ²⁺ ) crystals

Abstract

After direct electrolytical colouring or electron irradiation followed by illumination in the F centres absorption band of the NaCl:(Ag + +Ca 2+ ) crystal samples, a new centre has been observed denoted by us with Z(Ag -). The 300nm absorption band of this centre is close to the well known Ag a -absorption band from 275nm. The photoluminescence band of the Z(Ag -) centre is observed at 600 nm compared to the 440nm photoluminescence band of Ag a -. The photoluminescence band position depends on the nature of the divalent cation impurity peaking at 560 nm for Sr 2+ codoped samples. The obtained results prove that the Z(Ag -) centre is an Ag -ion perturbed by the divalent cation.

Electrolytic reduction of Tl+ ions in KCl crystals

“…The NaI:Tl + crystal emits blue emission by excitation with ionizing radiation such as X-rays and c-rays. NaCl:Ag À crystal is also useful as X-ray scintillator [2][3][4].…”