Актюбинский региональный государственный университет им. К. Жубанова пр. А. Молдагуловой, 34, Актобе, 030000, Казахстан
Received April 6, 2016.
At the registration of x-ray spectra in KI–Tl crystal the effect of low-temperature uniaxial deformation on the exciton’s mean free path before self-trapping was established. The analysis of the dependence of the in-tensity ratio of thallium center emission (2.85 eV) and luminescence of self-trapped excitons (π-component; 3.3 eV) on the degree of deformation in KI–Tl crystal (3.10–3 mol%) shows that the exciton’s mean free path before self-trapping is commensurate with the intertallium distance (20–27)a at the deformation of ε = 2%, while the corresponding value decreases to (5.35–27)a with the rise of ε ≥ 2–5%. Simulation results based on continuum approximation show that with temperature and the degree of low-temperature deformation increasing the height of excitons self-trapping potential barrier decreases, which is consistent with the reduction of the free exciton path length in KI–Tl crystal.
PACS: 62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances; PACS: 71.35.–y Excitons and related phenomena; PACS: 78.55.Fv Solid alkali halides.