Goldstone mode of a magnon Bose−Einstein condensate in MnCO<Subscript>3</Subscript>

The dependence of the enhancement of the Raman scattering on the size of a dielectric column is measured in structures with the spatial modulation of the height and lateral sizes of the dielectric coated with a thick metal layer (10–80 nm). It is established that, in the case of a thick metal coating (silver, gold, and copper coatings are used) at dimensions of the dielectric column close to the laser pump wavelength, considerable enhancement of the Raman signal oscillating upon the variation of the geometrical dimensions of the structure is observed. It is shown that the observed resonance enhancement of the Raman signal is associated with the transformation of the electromagnetic radiation into localized plasmon–polariton modes, and the efficiency of such transformation is determined by the commensurability of the wavelength of the plasmon–polariton mode and the planar size of the metal film. For different metal coatings, the dependence of the enhancement of the Raman scattering on the laser wavelength is measured.     

Quantitative evaluation of the effect of the medium on the thermodynamic parameters of conformational transitions of substituted 1,3-dioxanes in solutions and gases with PMR data

It was shown that the reaction field model satisfactorily describes the thermodynamic parameters of conformational equilibrium of 2-acetyl-substituted 1,3-dioxanes both as a function of the properties of the solvent and the phase state of the compound studied. Quantitative agreement was obtained between the experimental and theoretical values.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1782–1789, August, 1991.     

Analysis of the spatial structure of calixarenes in solutions by 2-D NMR (NOESY) spectroscopy

The spatial structure of calixarenes has been investigated by two-dimensional nuclear Overhauser effect spectroscopy (NOESY). A technique to study spatial structure of small molecules based on the combination of the method of small relaxation delays (Fast NOESY) and the method to measure relative cross-peak intensities has been proposed and approved. The given combination of methods allows one at a fixed time to reach a greater accuracy of measurements in comparison with other methods.     

Nuclear pseudoquadrupole resonance of <Superscript>141</Superscript>Pr in Van Vleck paramagnet PrF<Subscript>3</Subscript>

Nuclear pseudoquadrupole resonance of ¹⁴¹Pr in Van Vleck paramagnet PrF₃ has been observed in singlecrystal and micro- and nanopowder samples at a temperature of 4.2 K. The spectra of nuclear pseudoquadrupole resonance of ¹⁴¹Pr, as well as the spin-spin and spin-lattice relaxation parameters, have been obtained. The parameters of the nuclear spin Hamiltonian have been determined. It has been found that the parameters of the crystal electric field in nanocrystals differ strongly from those in microcrystals.