Ab initio defect based model for laser light generation and color image formation at the flat, edge and corner surfaces of Agar: F-A1 : Cs+ and F-A2 : Li+

The F-A1:Cs+ and F-A2:Li+ color centers at the flat, edge and corner surfaces of AgBr play important roles in laser light generation and color image formation. These two applications are investigated simultaneously by using quantum mechanical ab initio methods. As far as laser light generation is concerned, the calculated Stokes shifts suggest that laser activity is sensitive to the simultaneous effects of the vibrational coupling mode, the impurity cation, the coordination number of the surface ion, and the choice of the basis set centered on the anion vacancy. The FA(1):Cs+ and F-A2:Li+ color centers are suitable laser defects. The dependence of orientational destruction, recording sensitivity and exciton (energy) transfer on the impurity cation and the coordination number of the surface ion is clarified. The Glasner-Tompkins empirical rule is generalized to include the impurity cation and the coordination number of the surface ion. As far as color image formation is concerned, the supersensitizer was found to increase the sensitizing capabilities of two primary dyes in the excited states. Color image formation was found to be sensitive to the coordination number of the surface ion and the type of the impurity cation. On the basis of quasi Fermi levels, the difference in the sensitizing capabilities between the examined dyes in the excited states was determined. (c) 2005 Elsevier B.V. All rights reserved.