Studies of stimulated Raman scattering

The dependence of the excitation threshold and the intensity of the first Stokes component on the properties of the scattering material, the concentration of its molecules, and the exciting light intensity has been studied. It has been found that the intensity of stimulated Raman scattering lines depends exponentially on the intensity of the exciting light and the concentration of the scattering molecules. This dependence is in agreement with the theory developed.The author are gratful to P. A. Bazhuln, N. G. Basov, and A. M. Prokhorov for the present study.     

Proton NMR study of the central peak in ferroelastic KH3 (SeO3)2

Measurements of the temperature and the magnetic field dependence of the proton spin-lattice relaxation time T₁ in KH₃ (SeO₃)₂ show the presence of a dynamic narrow central peak in the local proton fluctuation spectrum the width of which is less than 0.1 MHz.     

KIO3 — The first ferroelectric with non-reorientable and non-180° switchable components of spontaneous polarization

It is shown that KIO₃ has two different kinds of ferroelectric phases in which the spontaneous polarization consists of two qualitatively different mutually perpendicular components: the non-reorientable component parallel to the 3-axis of the high-temperature phase, and the component reorientable at an angle which is obliged not to be equal to 180°.     

Low-temperature phase transitions and dynamics of ammonium in (NH4)3H(SO4)2 and [(NH4)1−x Rbx]3H(SO4)2 crystals

The (NH₄)₃H(SO₄)₂ and [(NH₄)_0.82Rb_0.18]₃H(SO₄)₂ crystals are investigated by dielectric spectroscopy, inelastic incoherent neutron scattering (IINS), and neutron powder diffraction. A comparative analysis of the data obtained is given. It is shown that the phase transitions II ? III, III ? IV, IV ? V, and V ? VII in the (NH₄)₃H(SO₄)₂ crystal are accompanied by changes in the orientation ordering of the NH ₄ ⁺ ions. In the [(NH₄)_0.82Rb_0.18]₃H(SO₄)₂ crystal, these phase transitions are completely suppressed and the long-range order inherent in the II phase is retained over the entire temperature range covered (6–300 K). It is revealed that this crystal at the temperature T _g≈70 K undergoes a transition to the dipole glass phase, which is attended by “freezing” the orientation disordering of the ammonium ions.     

Pseudosurface dispersion polaritons and their resonance excitation

The conditions for the transformation of surface polaritons (surface electromagnetic waves) into pseudosurface polaritons under the influence of perturbations are investigated. The transformation occurs because of the appearance of a weak energy loss flow typical of pseudosurface polaritons, which carries energy away from the surface of the solid. The dispersion polaritons existing at negative values of the dielectric constant are considered. The domain of existence of the pseudosurface polaritons is studied; their main characteristics and the parameters of the resonance excitation of these polaritons by a pumping wave are investigated.     

Silica gel-immobilized aluminum phthalocyanine complex as a heterogeneous catalyst for the synthesis of α-amino phosphonates

Aluminum phthalocyanine complexes immobilized onto silica gel (CPG-550 is controlled pore glass, MCM-41 is mesoporous molecular sieves) exhibited high catalytic activity and stability in the Kabachnik—Fields reaction.