Excitonic detectors of infrared and submillimeter radiation

The theory of new type detectors based on the quenching of secondary emission in direct-gap semiconductors (lines of Raman light scattering due to interaction between free and bound excitons in the crystal, and also bands of edge radiation) caused by IR or submillimeter radiation is proposed. The results obtained are confirmed by the experiment performed for CdS crystal excited by ultraviolet radiation of mercury lamp, at liquid helium temperature.     

Relaxed excited states and anomalous hyperfine structure of muonium centers in KBr

We report on the luminescence induced by positive muons implanted (with 4 MeV) into KBr crystal, which evidences a long-lived (lifetime=13.3 s excited state produced by muon radiolysis. The temperature dependence of the luminescence yield has a strong correlation with the amplitude of an anomalous muonium center: both are observed only below 50 K. This correlation strongly suggests that the muonium center is perturbed by the muon-induced excitons to cause the anomalous hyperfine structure. Moreover, the luminescence energy and decay time indicate that the observed luminescence is not associated with the intrinsic or impurity-related self-trapped excitons, but with a relaxed excited state specific to the muon(ium)-KBr system.     

Evaluation of electric hyperfine interactions inAuFe andCrFe

A detailed analysis of room temperature⁵⁷Fe Mössbauer spectra ofAuFe (5 at.% Fe) andCrFe (5, 10 at.% Fe) samples is presented. The deviation from Lorentzian line shape observed in the spectra indicates both thickness effects and structural disorder in these systems. The thickness effect has been taken into account using a new fitting technique that solves the transmission integral numerically rather than relying on the thin absorber approximation. The present results and analyses using both the thin absorber approximation and the full transmission integral methods on these alloy systems are compared with earlier results obtained on these alloy systems using only the thin absorber approximation.