ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Computational Chemistry and Molecular Modeling  (3)
  • Inorganic Chemistry  (3)
  • 42.75
  • 1995-1999  (6)
  • 1960-1964
  • 1995  (6)
Collection
Keywords
Publisher
Years
  • 1995-1999  (6)
  • 1960-1964
Year
  • 1
    Electronic Resource
    Electronic Resource
    Utopia dielectrica (1995)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 56 (1995), S. 523-531 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dielectric constant of a material is a macroscopic property that measures the reduction of the electrostatic forces between charged plates separated by the material, compared to a vacuum as intermediate material. It is next encountered as a scaling parameter in Coulomb's law for interacting charges, not only in the force, but also in the energy. In deriving the theory for dielectrics, the macroscopic nature is essential: Only then is the basic assumption that the dielectric material is homogeneous and isotropic a valid one. The appearance of the dielectric constant as a simple scaling factor in Coulomb's law has tempted many computational chemists to forget about the macroscopic nature of the dielectric and to apply the screened Coulomb's law between charges, supposedly in a low-dielectric medium such as proteins, in microscopic force fields. Optimization of force fields even led to distance-dependent “dielectric constants.” Another use of the dielectric constant appears in the dielectric continuum reaction field approaches for the computations of solvation energies and solvent effects. The solute is embedded in a cavity surrounded by the dielectric. Specific interactions between solvent molecules and solute are thus neglected. The cavity size and dielectric constants of interior and exterior are optimized for the model. The aim of this article is to show, by means of calculations on interacting point charges embedded in cavities surrounded by dielectrics and microscopic models of “low-dielectric” materials by explicit polarizabilities, that as far as the dielectric “constant” is concerned anything can happen, depending on the nature of the charges, the distance to the cavity boundary, the spatial arrangement of charges, and polarizabilities. Thus, a warning is issued to injudicious use of dielectric models in microscopic calculations. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560560855
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Komplexe mit N,N,N′,N′-Tetrakis(2-hydroxybenzyl)ethylendiamin (H4tben). Kristallstruktur von Ti(tben) (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 671-674 
    Details
    ISSN: 0044-2313
    Keywords: N,N,N′,N′-Tetrakis(2-hydroxybenzyl)ethylenediamine ; Complexes of Titanium(IV), Vanadium(IV), Manganese(IV), Tin(IV) ; Mass Spectra ; Mössbauer Data ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes with N,N,N′,N′-Tetrakis(2-hydroxybenzyl)ethylenediamine (H4tben). Crystal Structure of Ti(tben)The complexes of N,N,N′,N′-tetrakis(2-hydroxybenzyl)-ethylenediamine with titanium(IV), vanadium(IV), manganese(IV), and tin(IV) were synthesized and characterized by mass spectrometry. The Mössbauer date were evaluated for the tin compound. The molecular structure of the titanium(IV) complex was determined by X-ray structural analysis, crystallographic data see “Inhaltsübersicht”.
    Notes: Es wurden die Komplexe von N,N,N′,N′-Tetrakis(2-hydroxybenzyl)ethylendiamin mit Titan(IV), Vanadium(IV), Mangan(IV) und Zinn(IV) hergestellt und massenspektrometrisch charakterisiert. Für die Zinn-Verbindung wurden die Mössbauer-Daten ermittelt. Die Molekülstruktur des Titan(IV)-Komplexes wurde röntgenstrukturanalytisch bestimmt. N,N,N′,N′-Tetrakis(2-hydroxybenzyl)ethylendiaminato(4-)titan(IV): Raumgruppe P21/c (Nr. 14), Z = 4, 3949 Zahl der beobachteten Intensitäten, R = 0,0539, Gitterabmessung bei 20°C; a = 10,447(3) Å, b = 20,668(5) Å, c = 13,420(3) Å, b̃ = 101,93(5) Å
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210428
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Mangan(IV)-Komplexe mit dreizähnigen diaciden Liganden. Kristallstruktur von Acetylacetonato-salicylaldehydbenzoylhydrazonato(2-)-methanol-mangan(III)Frau Professor Brigitte Sarry zum 75. Geburtstag gewidmet (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 1483-1488 
    Details
    ISSN: 0044-2313
    Keywords: Manganese(IV) Chelates, Salicylaldehyde benzoylhydrazone and salicylhydrazone ; Mass Spectra ; Crystal Structure, Acetylacetonato-salicylaldehydebenzoylhydrazonato(2-)-methanol-manganese(III) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Manganese(IV) Complexes with Tridentate Diacidic Ligands. Crystal Structure of Acetyl-acetonato-salicylaldehydebenzoylhydrazonato(2-)-methanol-manganese(III)The manganese(IV) chelates of salicylaldehyde benzoylhydrazone and salicylaldehyde salicylhydrazone were synthesized by ligand exchange reactions using bis(acetylacetonato)manganese(II), tris(acetylacetonato)manganese(III) as well as manganese(III) acetate. The brown complexes show the expected molecular ions in the APCI mass spectra. As an intermediate compound acetyacetonato-salicylaldehydebenzoylhydrazonato(2-)-methanol-manganese(III) was isolated and characterized by X-ray structural analysis. Crystallographic data see “Inhaltsübersicht”.
    Notes: Durch Ligandenaustauschreaktion von Bis(acetylacetonato)mangan(II) und Tris(acetylacetonato)mangan(III) bzw. Mangan(III)-acetat mit Salicylaldehydbenzoylhydrazon und -salicylhydrazon wurden die Mangan(IV)-Chelate dieser Liganden dargestellt. Die braunen Verbindungen zeigen im APCI-positiv Massenspektrum die erwarteten Molekülionen. Für das Zwischenprodukt Acetylacetonato-salicylaldehydbenzoylhydrazonato(2-)-methanol-mangan(III) wurde die Kristall- und Molekülstruktur bestimmt: Gitterabmessungen bei 293 K; a = 754,3(2) pm, b = 1 027,3(6) pm, c = 1 357,4(5) pm, α = 79,64(4)°, β = 76,51(3)°, γ = 70,45(4)°, Raumgruppe P1 (Nr. 2), Z = 2, 3297 unabhängige Reflexe, R = 3,84%.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210908
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Strukturverfeinerung und magnetische Messungen an Mn2SnS4 (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 1600-1604 
    Details
    ISSN: 0044-2313
    Keywords: Dimanganese tin tetrasulfide ; crystal structure ; magnetism ; IR ; Raman ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure Redetermination and Magnetic Studies on Mn2SnS4The crystal structure of Mn2SnS4 was redetermined by single crystal and powder X-ray studies. It has a deficient NaCl superstructure crystallizing in the orthorhombic space group Cmmm proposed by Wintenberger and Jumas in 1980 (Z = 2, a = 740.7(1), b = 1047.5(1) and c = 366.7(2) pm, Rf = 1.4% for 266 unique reflections with I 〉 0σ1). Some additional reflections, which are not compatible with this cell, can be refined assuming formation of twinned trilling crystals. Mn2SnS4 undergoes antiferromagnetic ordering below 160 K. The effective magnetic moment μeff of Mn2+ is 5.92 B.M. The IR and Raman spectra display 5 and 3 bands in the range 150-320 cm-1, respectively.
    Notes: Die Kristallstruktur von Mn2SnS4 wurde mittels Röntgeneinkristall- und Röntgenpulver-Messungen nachbestimmt. Mn2SnS4 besitzt eine defiziente NaCl-Überstruktur und kristallisiert, wie von Wintenberger und Jumas [6] vorgeschlagen, in der orthorhombischen Raumgruppe Cmmm (Rf = 1,4% für 266 unabhängige Reflexe mit I 〉 0σ1). Die in dieser Zelle nicht indizierbaren Reflexe können unter der Annahme einer Mehrlingsbildung verfeinert werden. Das effektive magnetische Moment μeff von Mn2+ beträgt 5,92 B.M. Unterhalb 160 K liegt eine antiferromagnetische Ordnung vor. Die IR-und Raman-Spektren zeigen 5 bzw. 3 Banden im Bereich von 150-320 cm-1.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210927
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Implementation of reaction field methods in quantum chemistry computer codes (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 16 (1995), S. 37-55 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The embedding of a quantum mechanically described subsystem by classical representations of its surroundings is reviewed. The choices for a distributed monopole representation and a distributed (group) polarizability representation, as well as the continuum approach to model bulk effects, are discussed. Focus is on the practical implementation of the classical description in quantum chemistry codes (in particular, HONDO8.1). Expressions are given for the self-consistent coupling between the classical partitions (dipole polarizabilities and boundary surface dipoles and charges) and for the coupling between classical and quantum partitions. The latter is mediated through expanded, rather than exact, potentials and fields. In this way, the computation of only a limited number of formal interactions between unit charge distributions located at the expansion centers suffices to evaluate the reaction field contributions. The electronic part of the coupling can be included in the Hamiltonian via the Fock matrix. The field operators, as well as the one- and two-electron matrix elements over the basis functions, are simple. The expressions for these are given explicitly.Nonequilibrium potentials and Monte Carlo sampling over classical degrees of freedom have been added to better mimic experimental conditions. © 1995 by John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540160105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Implementation of reaction field methods in quantum chemistry computer codes (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 16 (1995), S. 1445-1446 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540161113
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...