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It is shown that such parameters of GaN/AlxGa1—xN superlattice as the period, built-in strain, composition of the alloy, and individual layer thicknesses can be extracted from the energy positions, intensities, and line shapes of various optical and acoustic modes detected in Raman scattering.

We present the results of a detailed study of the first- and second-order Raman scattering and IR reflection from hexagonal InN layers grown on (0001) and (11-02) sapphire substrates. All six Raman active optical phonons were measured and assigned: E2(low) at 87 cm—1, E2(high) at 488 cm—1, A1(TO) at 447 cm—1, E1(TO) at 476 cm—1, A1(LO) at 586 cm—1, and E1(LO) at 593 cm—1. The static dielectric constants of InN for the ordinary and extraordinary directions were estimated to be ɛ⊥0 = 13.1 and ɛ∥0 = 14.4, respectively. The phonon dispersion curves and phonon density-of-state function for hexagonal InN were calculated by scanning throughout the BZ.

Crude oil samples irradiated by ^6^0Co @c-irradiation have been investigated for olefins. Olefin concentrations were found to increase in oils in the proportion with the irradiation dose. No influence of S and/or asphaltene concentrations in oils on olefin formation was observed. The olefin hydrocarbons were found to be generated mainly through non-selective dehydrogenation of saturated hydrocarbons in the oils, rather than cleavage of C-C bonds of aromatic and/or resinous compounds. Structures of the laboratory-prepared radiogenic olefins were studied (by GC,^1H and ^1^3C NMR) and compared with structures of alkenes isolated from Paleozoic and Precambrian oils. The results of comparison do support the radiolytic concept of olefin formation in crude oils. There are also reported data on the olefin concentrations measured in about 700 oils from 5 basins of the Former Soviet Union, in which the age of oil formations ranges from Precambrian up to Cainozoic. A tendency for olefins to occur more often in oils from old and cold deposits has been established.

The CRYME (CRYstal MEchanics) code is written in FORTRAN and adapted to IBM PC. It enables to use a wide scope of phenomenological approaches worked out for description of potential functions of crystals and theoretical investigation of solids. These functions range from the simplest short-range ones like the Valence-Force or Born-von Karman fields, to the most elaborated versions of the Shell-Model. The investigations include lattice vibrations and related properties, elastic, dielectric and piezoelectric tensors, thermodynamical characteristics, a lattice equilibrium geometry minimizing the internal energy of the crystal potential and strength of the electrostatic field of atomic sites. CRYME enables to calculate the above-mentioned properties for a stress-free lattice, or for a crystal under hydrostatic compression, anisotropic macroscopic tension or under an external electric field.