Polarizable molecular interactions in condensed phase and their equivalent nonpolarizable models

Earlier, using phenomenological approach, we showed that in some cases polarizable models of condensed phase systems can be reduced to nonpolarizable equivalent models with scaled charges. Examples of such systems include ionic liquids, TIPnP-type models of water, protein force fields, and others, where interactions and dynamics of inherently polarizable species can be accurately described by nonpolarizable models. To describe electrostatic interactions, the effective charges of simple ionic liquids are obtained by scaling the actual charges of ions by a factor of 1/sqrt(eps_el), which is due to electronic polarization screening effect; the scaling factor of neutral species is more complicated. Here, using several theoretical models, we examine how exactly the scaling factors appear in theory, and how, and under what conditions, polarizable Hamiltonians are reduced to nonpolarizable ones. These models allow one to trace the origin of the scaling factors, determine their values, and obtain important insights on the nature of polarizable interactions in condensed matter systems.Comment: 43 pages, 3 figure

Ore-forming Сonditions of the Blagodat Gold Deposit in the Riphean Metamorphic Rocks of the Yenisey Ridge According to Geochemical and Isotopic Data

Neodymium and strontium isotopic composition and rare earth elements (REE) distribution pattern have been determined in whole rocks and minerals were separated from host metamorphic rocks and disseminated sulfide ores of the Blagodat gold deposit. Isotopic data are given to construct few isochrones that could be reflected an age of main stages of metamorphic and metasomatic alteration in rocks varieties during a successive accumulation of gold in structural traps. The significant temporal range in the forming of the studied rocks can be interpreted as an evidence of multi-stage tectonic destruction accompanying with trust-folding processes, shear deformations and development of local fracture zones that had place from the Late Riphean to Middle Paleozoic time. According to isotopic data basic ore-forming processes were realized in the relatively narrow interval from 690 to 750 Ma that correspond to a beginning of continental rifting on the western margin of Siberian craton. Chemistry and trace element distribution are closed for host and auriferous schists and mainly showed differences in the composition initial sedimentary units. The middle negative value εNd (from -14 to -16) and very high positive value εSr (from +570 to +725) are mostly corresponded to that of upper continental crust matter. The role of synchronic granite intrusions in the studied area can be only estimated due to a generation of thermal energy and crustal fluids

X‐ray diffraction and dielectric investigations of ferroelectric PbZr0.958Ti0.042O3, antiferroelectric PbZrO3 and PbHfO3 single crystals in superstrong electric fields up to 30 MV/m

Ferroelectric rhombohedral phase (R3m) in PbZr0.958Ti0.042O3 and antiferroelectric orthorhombic phase (Pbam) in PbZrO3 and PbHfO3 are examined via X‐ray diffraction and dielectric methods in DC electric fields of 0 ≤ Е ≤ 3.0⋅107 V/m. Induced polarization Pi(E) and piezoelectric coefficient d33(Е) are found as functions of field from the experimental dependences of unit‐cell parameters and dielectric permittivity on the electric field E and exhibit similar behavior for BaTiO3 and PbZr0.958Ti0.042O3 single crystals. The unit‐cell parameters of antiferroelectric phases in PbZrO3 and PbHfO3 single crystals remain constant, while the electric fields correspond to induced phase transitions, and the dielectric permittivity slightly increases with the electric field

Electrochemically synthesized Pt/TiO2-C catalysts for direct methanol fuel cell applications

The Pt/TiO2-C catalysts with different TiO2 loadings have been prepared by electrochemical oxidation/dispersion, and their good catalytic activity in CO stripping and methanol electrooxidation reactions has been shown

Electrochemically synthesized Pt/TiO2-C catalysts for direct methanol fuel cell applications

The Pt/TiO2-C catalysts with different TiO2 loadings have been prepared by electrochemical oxidation/dispersion, and their good catalytic activity in CO stripping and methanol electrooxidation reactions has been shown

Ore-forming Сonditions of the Blagodat Gold Deposit in the Riphean Metamorphic Rocks of the Yenisey Ridge According to Geochemical and Isotopic Data

Neodymium and strontium isotopic composition and rare earth elements (REE) distribution pattern have been determined in whole rocks and minerals were separated from host metamorphic rocks and disseminated sulfide ores of the Blagodat gold deposit. Isotopic data are given to construct few isochrones that could be reflected an age of main stages of metamorphic and metasomatic alteration in rocks varieties during a successive accumulation of gold in structural traps. The significant temporal range in the forming of the studied rocks can be interpreted as an evidence of multi-stage tectonic destruction accompanying with trust-folding processes, shear deformations and development of local fracture zones that had place from the Late Riphean to Middle Paleozoic time. According to isotopic data basic ore-forming processes were realized in the relatively narrow interval from 690 to 750 Ma that correspond to a beginning of continental rifting on the western margin of Siberian craton. Chemistry and trace element distribution are closed for host and auriferous schists and mainly showed differences in the composition initial sedimentary units. The middle negative value εNd (from -14 to -16) and very high positive value εSr (from +570 to +725) are mostly corresponded to that of upper continental crust matter. The role of synchronic granite intrusions in the studied area can be only estimated due to a generation of thermal energy and crustal fluids