Determination of Oscillator Strengths for the Tl-Centers in Potassium Dihydrogen Phosphate Single Crystals

Abstract

Thallium concentration in KDP: Tl crystals is measured by spectroscopic analysis of their aqueous solutions. It is confirmed that the strengths of the five uv absorption bands (A_xy, A_z, B_xy, C_xy and C_z) are linearly proportional to the thallium ion concentration in the crystal. Oscillator strengths of these bands are also determined and are compared with those for Tl⁺-like centers in KCl. The oscillator strength of the crystal field induced transition associated with the B_xy band in KDP: Tl is 0.10 at 77 K, which is about one order of magnitude larger than that of the phonon induced transition associated with the B band in KCl: Tl.