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This article deals with the absorption, excitation and luminescence spectra of frozen aqueous solutions of the halide salts and acids with molecular anion impurities CN - , SCN - , SeCN - and CNO - . It is shown that the spectra at 4.2°K display vibronic structure which is explained by the interaction of electronic transition with intramolecular oscillations of the impurity. Conclusions are also deduced from the results of investigation of temperature dependence of the quantum emission efficiency and the Raman spectra of such systems.

The present work considers a method of diagonalization of the energy operator of a system of valence electrons in a simple model of a semiconductor, and in a simple model of a metal. The results obtained are used in the theory of superconductivity and in the theory of superfluidity.

Using a diffusion cloud chamber in a magnetic field several μ − -mesic atomic and molecular process are studied experimentally in hydrogen. The following quantitative data are obtained: the cross section for the elastic scattering of pμ-mesic atoms on protons σ pp = (1.7 −0.5 +0.4 ) × 10 −19 cm 2 ; the rates of transfer of a μ-meson from the proton to deuterons and complex nuclei (C and 0), reduced to the density of liquid hydrogen, λ d = (0.95 −0.21 +0.34 )× 10 10 sec −1 and λ Z = (1.2 −0.5 +0.8 )×10 10 sec −1 ; and the rate of formation of mesic molecular ions ppμ in liquid hydrogen λ pp μ = (0.6 −0.5 +0.8 ) × 10 6 sec −1 . The experimental values λ d , λ ppμ and λ Z agree satisfactorily with the theoretical predictions, which confirms the validity of the mechanisms proposed in the theory for the processes. The cross section σ pp proved to be close to the theoretical value calculated without taking into account the hyperfine structure of the mesic atom pμ. The possibility is not excluded, however, of a rapid transition to a lower state with total mesic atom spin F = 0. The determination of the absolute value of λ ppμ in this paper makes it possible to obtain the absolute probabilities of several μ-mesomolecular processes on the basis of the above value.