On the Contribution of the Long-Range Scattering Potential in the Process of Multiphoton Above-Threshold Ionization of Atoms in the Laser Field

Journal of Experimental and Theoretical Physics - Using the quantum mechanical analysis of stimulated bremsstrahlung of an electron on an electrostatic potential in the field of a strong...     

On solutions of almost hypoelliptic equations in weighted Sobolev spaces

It is proved that if P(D) is a regular, almost hypoelliptic operator and

Unusual hydrogen bonding in L‐cysteine hydrogen fluoride

L‐Cysteine hydrogen fluoride, or bis(L‐cysteinium) difluoride–L‐cysteine–hydrogen fluoride (1/1/1), 2C₃H₈NO₂S⁺·2F⁻·C₃H₇NO₂S·HF or L‐Cys⁺(L‐Cys...L‐Cys⁺)F⁻(F⁻...H—F), provides the first example of a structure with cations of the `triglycine sulfate' type, i.e.A⁺(A...A⁺) (where A and A⁺ are the zwitterionic and cationic states of an amino acid, respectively), without a doubly charged counter‐ion. The salt crystallizes in the monoclinic system with the space group P2₁. The dimeric (L‐Cys...L‐Cys⁺) cation and the dimeric (F⁻...H—F) anion are formed via strong O—H...O or F—H...F hydrogen bonds, respectively, with very short O...O [2.4438 (19) Å] and F...F distances [2.2676 (17) Å]. The F...F distance is significantly shorter than in solid hydrogen fluoride. Additionally, there is another very short hydrogen bond, of O—H...F type, formed by a L‐cysteinium cation and a fluoride ion. The corresponding O...F distance of 2.3412 (19) Å seems to be the shortest among O—H...F and F—H...O hydrogen bonds known to date. The single‐crystal X‐ray diffraction study was complemented by IR spectroscopy. Of special interest was the spectral region of vibrations related to the above‐mentioned hydrogen bonds.     

L‐Argininium phosphite – a new candidate for NLO materials

In order to investigate the possibility of salt formation in the L‐Arg–H₃PO₃–H₂O system, single crystals of L‐argininium phosphite, C₆H₁₅N₄O₂⁺·H₂PO₃⁻, were prepared by evaporation of an aqueous solution containing equimolar quantities of L‐arginine and phosphorous acid. The asymmetric unit contains one L‐argininium(+) cation and one phosphite [HPO₂(OH)]⁻ anion. The phosphite anions form chains parallel to [010] by O—H...O hydrogen bonding, with an O...O distance of 2.630 (3) Å. The protonated amine and guanidyl groups of the L‐argininium(+) cations form N—H...O hydrogen bonds with the carboxylate groups and anions. The IR and Raman spectra are discussed in relation to the crystal structure. The salt displays nonlinear optical (NLO) properties. Another salt was obtained from a solution with a 1:2 molar ratio of components, but was characterized by vibrational spectra only.     

Short-term changes in delta(13)C and delta(15)N signatures of water discharged from grazed grasslands

The composition of dissolved organic matter (DOM) in a soil is the product of a variety of soil processes. Changes in the composition of DOM in water discharged from soil should, therefore, give an important insight into modifications in these soil processes. We hypothesise that these processes in soils, under different grassland management regimes, would be affected to different extents by the short-term disturbance of a storm event and that evidence of this could be detected in delta(13)C and delta(15)N signatures in drainage and surface runoff waters. During a storm event we collected discharge waters from 1 ha grassland lysimeters, with or without artificial drainage, which received contrasting fertiliser inputs, and delta(13)C and delta(15)N signatures were determined. Changes in (13)C enrichment during the storm event were clearly identifiable, as were differences between plots for (13)C and (15)N, illustrating that this technique has potential to be a useful tool for identifying and investigating short- and long-term changes in soil organic matter dynamics. Copyright 1999 John Wiley & Sons, Ltd.     

Fermi Surface Topology Signature on the High Harmonics Generation in Graphene-Like Nanostructure

Journal of Experimental and Theoretical Physics - The response of high harmonics of a laser field to the change of Fermi surface topology in graphene-like nanostructures during the process of the...     

Bis-l-Cysteinium sulfate and l-cysteinium methanesulfonate

Structural Chemistry - Two new crystalline compounds of l-cysteine have been obtained: bis-l-cysteinium sulfate (l-CysH)2SO4 (I) and l-cysteinium methanesulfonate (l-CysH)CH3SO3 (II). Both crystal...     

Synthesis and Biological Activity of New 2-{[6-Methyl-2-(pyrrolidin-1-yl)pyrimidin-4-yl]oxy}acetohydrazide Derivatives

Russian Journal of General Chemistry - The reaction of 6-methyl-2-(pyrrolidin-1-yl)pyrimidin-4(3H)-one with methyl chloroacetate, followed by hydrazinolysis, gave...     

Influence of solid-state biaxial orientation on the adhesion between poly(ethylene terephthalate)/tie layer/isotactic polypropylene multilayer films

Current state-of-the-art packaging films typically consist of solid-state stretched multilayer polymer systems, in which each of the polymer layers provides a specific property. Often these polymer film layers are incompatible and need to be glued together by so-called “tie layers.” In this article, we apply a novel biaxial orientation technique to examine the effect of solid-state biaxial stretching on the adhesive behavior of a model multilayer system consisting of poly(ethylene terephthalate) and isotactic polypropylene, as an example of two typical incompatible base layers, glued together by a common tie layer. Two main factors affecting the adhesion, the temperature at which the biaxial stretching is performed and the thickness of the tie layer, are discussed in detail. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 446–454