Dependence of the steepness of the exponential absorption tail on the chemical composition of materials

The quantity characterizing the steepness of the exponential tail of the fundamental absorption edge is studied. It is shown, that the magnitude of of binary compounds can be roughly estimated from their chemical composition in a way described in this paper.Boní II, Praha 4, Czechoslovakia.The author thanks Ing. D. Leal, CSc for his valuable discussions concerning this work.     

Lgft-Values of forbidden beta-transitions

In this paper the influence of the interference and nuclear charge on lgft-values is investigated. It is shown that interference by most of 1st and 2nd forbidden transitions is weak and, further, that the nuclear charge influence, compared theoretically, is in good agreement with experimental results.     

Establishment of activation energy of subgrain growth in strongly deformed polycrystalline nickel

The paper describes the measurement of the subgrain size of nickel with a purity of 99.80%, after deforming to 97.5% and annealing up to 200°, 400°, 450° and 500°C. It was ascertained that the following relation holds in a temperature interval 400–500°C

$$\log t = \Delta {\rm E}/2.3R \times 1/T + log B ,$$     

Green's functions for body-centred cubic lattices

The presented paper contains the tables of Green's functions for bcc lattices for outband frequencies 1·0/ _m 1·6. The central-force model is used, the interaction with 8 nearest and 6 next-nearest neighbours is considered and the number of different Green's functions is fairly decreased by symmetry. Numerical difficulties arising by computing Green's functions are discussed. The derivation of symmetry relations for a dynamical matrix is generalized for the matrix of Green's functions.     

Coulometrische permanganatometrische bestimmung von wasserstoffperoxyd

A method has been developed for the quantitative coulometric permanganatometric micro-determination of hydrogen peroxide. The end-point is ascertained by the colour changes of the indicators ferroin, and nitro-ferroin respectively     

Exciton system heating in ZnSe single crystals under laser excitation

The way to determine the effective temperature of the excitonic system from the study of the edge luminescence high energy region is motivated. Experimental data on the exciton heating in ZnSe single crystals under laser excitation are presented. The effective temperature of excitons T_x has reached 158 K at the lattice temperature T_L = 77 and the peak excitation intensity 2.7 MW cm^?2 (hv₀ = 3.50), while the excess temperature of the excitons (T_x ? T_L) increases as a square root of the pump intensity. Exciton-hot-electron, exciton-hot-photon, exciton-exciton interactions and excitonic Auger process are considered as possible causes of the exciton system heating.