Abstract
The absorption spectra of [NH2(C2H5)2]2CuCl4 crystals grown from the ethanol solution (DEACC-I) as well as of [NH2(C2H5)2]2ZnCl4 · nH2O (DEAZC) and ammonium alum NH4Al(SO4)2 · 12H2O crystals grown from the water solutions have been investigated in a visible region. The influence of ionizing irradiation on these spectra was studied as well. It was shown that DEACC-I crystal undergoes the thermochromic phase transition at higher temperature ( = 324.5 K) and manifests a higher sensitivity to the influence of ionizing irradiation in comparison with the analogous crystal grown from water solution (DEACC-II). It has been found that the nature of the radiochromic changes in DEAZC and ammonium alum is connected with localization of excitons on the newly created structural defects.