[en] The X-ray thermal scattering intensities from (100), (001) and (110) planes of CdS and CdSe have been measured. The CuKsub(α) radiation has been used to establish the mean square displacements along the directions [100] and [001]. The separation of one phonon scattering intensity was performed by the use of the temperature dependence of thermal diffuse scattering intensity in the region 93-293 K. The relation between scattering and dynamic matrices was used to separate the contributions of accoustic and optical modes in the intensity. The phonon frequency dependencies on the wave vector along [001] direction have been determined

[en] The intensity of the X-ray thermal scattering on the crystallographic (002) and (200) planes of the hexagonal CdSe has been measured in the range 93-293 K. The one and two phonon scattering intensities at 293 have been found according to the temperature dependence. The distribution of the mean square displacements of the longitudinal and perpendicular CdSe lattice vibrations in Brillouin zone along the c axis of the third order and in the plane (a, b) which is perpendicular to c, has been determined using the absolute intensity of the one-phonon scattering. The characteristic temperatures and mean square displacements of the CdSe lattice for thermal vibrations along and across the main c axis of the lattice are shown to be 138, 186 K, and 0.0269, 0.0201 nanometer, respectively. An agreement with the values, obtained using the intensity of the coherent scattering, has been observed

[en] The Compton profiles (CP) of valence electrons and valence electron momentum distribution functions (VEMDF) have been determined by use of the experimentally measured CP. The valence electron distribution peculiarities in hexagonal CdS have been discussed by comparing CP and VEMDF, experimentally determined and calculated including ionization and excitation of atoms in valence states

[en] Intensities of diffractional lines of hexagonal CdS and CdSe have been measured in the interval 93-673 K. Characteristic temperatures and mean square displacements of the lattices and sublattices along the axis of the third order c and in the plane (a,b), perpendicular to the axis c, have been determined according to the intensity lines of diffraction spectra. Temperature dependence and anisotropy of characteristic temperatures, mean square displacements and expansion coefficients of crystals have been investigated in the interval 93-673 K. It has been shown that characteristic temperatures depend on the temperature in the region of low temperatures and have maximums 190 and 170 at 143 and 193 K for CdS and CdSe respectively. The characteristic temperatures of CdS and CdSe in the high temperature region (T> 423 K) are constant and equal to 185 and 170 K. Mean square displacements along the axis c are greater, and expansion coefficients lower than in the plane (a,b). It has been shown that vibrations of lattice spectrum of CdS differs to a greater extent from that approximated by Debye than the spectrum of CdSe