The quantum DELL system

Letters in Mathematical Physics - We propose quantum Hamiltonians of the double-elliptic many-body integrable system (DELL) and study its spectrum. These Hamiltonians are certain elliptic functions...     

Synthesis and physicochemical study of di(1,3,7-trimethylpurine-2,6-dione) 12-tungstosilicate (C8N4O2H11)2H2SiW12O40

The di(1,3,7-trimethylpurine-2,6-dione) dihydrogen 12-tungstosilicate (C₈N₄O₂H₁₁)₂H₂SiW₁₂O₄₀ (I) was synthesized and studied using chemical methods, IR and ¹H NMR spectroscopy, X-ray phase analysis, and the thermogravimetry technique.     

Role of spin-orbit coupling and hybridization effects in the electronic structure of ultrathin Bi films

The electronic structure of Bi(001) ultrathin films (thickness > or =7 bilayers) on Si(111)-7x7 was studied by angle-resolved photoemission spectroscopy and first-principles calculations. In contrast with the semimetallic nature of bulk Bi, both the experiment and theory demonstrate the metallic character of the films with the Fermi surface formed by spin-orbit-split surface states (SSs) showing little thickness dependence. Below the Fermi level, we clearly detected quantum well states (QWSs) at the M point, which were surprisingly found to be non-spin-orbit split; the films are "electronically symmetric" despite the obvious structural nonequivalence of the top and bottom interfaces. We found that the SSs hybridize with the QWSs near M and lose their spin-orbit-split character.     

Exhaustive acylation of dihydroquercetin

Reaction of dihydroquercetin with acid chlorides of higher and functionalized carboxylic acids was studied with the purpose of creation of new pharmaceuticals.     

Dicationic polysiloxane ionic liquids

Dicationic ionic liquids with bis(trifluoromethylsulfonyl)imide anions and dimethylimidazolic moieties linked by the polymeric siloxane chain in the cation structure have been synthesized. Thermal stability of the compounds synthesised was studied by TGA; glass transition temperatures, viscosities and volatility in vacuo were measured. Applicability of these ionic liquids as heat carriers under high dynamic vacuum conditions is shown.     

Synthesis, structure, solid-state thermal decomposition and magnetic properties of binuclear Nd, Gd and Eu cymantrenecarboxylates

New rare-earth cymantrenecarboxylates [Nd₂(μ₂-OOCCym)₄(OOCCym)₂(THF)₄] (1) and [Ln₂(μ₂-OOCCym)₄(OOCCym)₂(THF)₄]·THF (Ln = Gd (2), Eu (3); Cym = (η⁵-C₅H₄)Mn(CO)₃) were synthesized starting from carboxycymantrene and lanthanide nitrates, and characterized by X-ray diffraction. The crystals of 1-3 consist of isolated binuclear molecules; the Ln atoms are eight-coordinate. The magnetic properties of 2 are indicative of antiferromagnetic coupling between the Gd atoms at liquid helium temperature. The thermal decomposition of complexes 1-3 was studied by differential scanning calorimetry (DSC) and thermogravimetry (TG). According to the X-ray powder diffraction patterns, the thermal decomposition of the complexes in air affords a mixture of LnMn₂O₅ and Mn₂O₃ as the final products.     

Synthesis and Structural Study of 3,5-Cyclophosphorus Derivatives of 1,2-O-Alkylidene-6-Desoxy-6-Halogeno-α-D-Glucofuranoses

Abstract

Reactions of 3,5-halogenocyclophosphata of 1,2-O-alkylidene-6-desoxy-6-halogeno-α-D-glucofuranoses with water, alcohols, and amines were studied, which permit the obtaining of corresponding 3,5-cyclophosphates, their salts, and amides:     

Magnetostructural correlation for the Gd complexes with bridging oxygen

The dependence between the energy of magnetic exchange interaction J _Gd-Gd′ and the distance between gadolinium atoms in the binuclear structure D _Gd...Gd′ was constructed on the basis of our and literature experimental data for 34 gadolinium complexes with the [Gd₂O₂] core. The character of the established dependence is similar to the Bethe-Slater curve. The obtained correlation indicates the possibility to predict the character of interaction in the Gd complexes built of binuclear fragments with the [Gd₂O₂] core depending on the single parameter, namely, distance D _Gd...Gd′. The validity of this correlation was tested using as examples four binuclear gadolinium complexes obtained by the authors.     

Polarization characteristics of the “forbidden” second optical harmonic of femtosecond laser pulses in a bacteriorhodopsin solution

The generation of the second harmonic of femtosecond laser pulses in a bacteriorhodopsin solution has been experimentally studied for various wavelengths and polarization states of radiation at the fundamental frequency. The polarization properties of the effect are analyzed under various experimental conditions. The nature and properties of the signal are treated as the manifestation of a superposition of nonlinear optical effects of various orders (the second and the fourth). The second-order effects can have both an electric-dipole and a magnetic-dipole or electric-quadrupole character. In analyzing fourth-order processes, besides the direct electric-dipole contribution, the possibility of the participation of cascade processes at second-and third-order nonlinearities is also allowed. Zh. éksp. Teor. Fiz. 112, 97–114 (July 1997)