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
  • 1
    Electronic Resource
    Electronic Resource
    Tetracritical and novel tricritical points in sulfur solutions: A Flory model for polymerization of rings and chains in a solvent (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 5030-5055 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A model for equilibrium polymerization of rings and chains in a solvent is solved in a Flory-like approximation. The presence of polymeric rings leads to interesting new kinds of phase equilibrium and higher order critical points. We find a higher order critical point analogous to a tetracritical point in a corresponding magnet, at which four phases come into simultaneous equilibrium, as well as novel tricritical points where three critical lines meet at a cusp. The resulting phase diagrams give improved agreement with those of sulfur solutions with cis-decalin and with ortho-xylene. The model has interesting consequences for the predicted behavior of magnets as well. It reduces to the earlier theories of Tobolsky and Eisenberg, Scott, Wheeler, and Pfeuty, and Petschek, Pfeuty, and Wheeler in various limits, but exhibits new behavior not seen in any of the previous theories.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456546
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Chemical reaction driven phase transitions and critical points (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 7097-7112 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Two simple examples of model (mean-field) equations of state for phase equilibrium in chemically reactive systems are examined for "unexpected'' phase equilibria. They are, essentially, exactly soluble and give classical critical behavior. One of these leads to a lower critical solution temperature that results in closed-loop coexistence curves similar to those seen in hydrogen-bonding mixtures. The second leads to less familiar, but interesting phase diagrams that exhibit a phenomenon analogous to critical azeotropy. The same phenomena occur in two examples of lattice gas models the partition functions of which can be mapped exactly to that of the Ising model thus resulting in nonclassical critical behavior. These models demonstrate how a chemical reaction can provide a mechanism leading to interesting phase equilibria and critical phenomena.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457327
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Dissociative model of water clusters (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 9071-9080 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A model of water is introduced that dissociates into either ionic or covalent molecular fragments. The model is based on a semiempirical calculation embedded in a molecular mechanics approach. It contains electronic degrees of freedom that allow the calculation of partial charges that vary smoothly from the bound state to the dissociated states. The hydrogen bond is modeled classically with Coulomb interactions, and shows significant improvement in predicting cluster behavior by adding directional character via an overlap between a lone pair orbital on oxygen and the hydrogen of an adjacent molecule. An implicit bond polarization is present due to stretching bonds and charge transfer when the hydrogen bonds are formed. The energetic and geometric properties of water dissociation products, molecular clusters, and ionic clusters are presented. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478828
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Semiempirical methodology for simulating covalently bonded materials: Application to silicon (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 4632-4641 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A recently introduced semiempirical methodology is used to model and simulate silicon via molecular dynamics. This approach is capable of grasping essential qualitative and quantitative features of the coupling between the electronic coordinates and the geometric structure. Properties of the bulk diamond crystal, the melt and amorphous solid states are obtained using optimization techniques and molecular dynamics simulations. The pair distribution function of the amorphous state is in excellent agreement with experimental and other molecular dynamics simulation results. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471157
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Erratum: "Solubility limits of silicate melts" [J. Chem. Phys. 106, 6460 (1997)] (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 2044-2044 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.476781
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Solubility limits of silicate melts (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 6460-6469 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A statistical mechanical model of silica melt is presented in which metal oxides are incorporated into the bonding network. In this approach a Flory-type lattice model for binary silicate melts is coupled with a set of chemical reactions that determine the extent of metal oxide incorporation into the silica network and regulate the distribution of nonbridging oxygens around a central silicon. The theory produces two- and three-phase coexistence curves over a range of parameter space. The three-phase equilibrium regions coalesce to critical end points, where two of the three phases have become critical, and to a nonsymmetric tricritical point, where all three phases have simultaneously become critical. The theory captures the qualitative behavior and essential features of simple binary silicate melts. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.474122
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Phase diagrams of "living" polymers at fixed initiator concentrations (1992)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 9479-9487 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100202a075
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Living poly-α-methylstyrene near the polymerization line. II. Phase diagram in methylcyclohexane (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 98 (1993), S. 9873-9880 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present the experimental determination of the liquid–liquid coexistence curve of living poly-α-methylstyrene (initiated by n-butyllithium) in methylcyclohexane. We measured the coexistence curve by measuring the phase separation temperatures of a set of samples of different mole fractions of the initial monomer, x*m. All the samples had the same ratio, r(=0.008), of the mole fraction of the initiator to the mole fraction of the monomer. We also measured the polymerization line by measuring the temperatures at which increases in viscosity signaled the onset of polymerization. The measured upper critical solution point for this system is at a temperature of 274±1 K and at x*m = 0.18 ± 0.02. At this x*m, the polymerization temperature Tp is 285 K, well above the critical temperature. Tp decreases as x*m decreases, so that the polymerization line meets the coexistence curve at about x*m = 0.12. We compare the predictions of a lattice model which is equivalent to the mean field limit of the dilute n→0 magnet model for constant r to the measured phase diagram and find good qualitative agreement. Better agreement might result if we could solve the model without taking the mean field limit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.464366
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Si adatom binding and diffusion on the Si(100) surface: Comparison of ab initio, semiempirical and empirical potential results (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 1044-1056 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The binding energies and configurations for single Si adatoms on the Si(100) surface are investigated theoretically. Detailed comparisons between previously published and new calculations using classical potentials, semiempirical formulations, and density functional theory (DFT) are made. The DFT calculations used both the plane-wave-pseudopotential approach in a periodic slab geometry and the Gaussian-orbital based all-electron approach employing cluster geometries. In the local-density approximation excellent agreement between the cluster and slab results was obtained. Inclusion of gradient corrections to the exchange-correlation energy significantly improves absolute binding energies and changes relative energies by as much as 0.3–0.5 eV depending on the particular exchange-correlation functional used. Binding energies and relative energies obtained using the classical potentials disagree with the gradient corrected DFT energies at about the 0.6–0.9 eV level, and most find qualitatively different local minima from those found in the DFT calculations. The semiempirical approaches give results intermediate in quality between those of the classical potentials and the ab initio calculations. Analysis of the energies and binding site geometries provides insight into the shortcomings of some of the classical potentials. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469453
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    facet.materialart.
    Unknown
    Migration of O vacancies in α-quartz: The effect of excitons and electron holes (2001)
    American Physical Society
    Details
    Publication Date: 2001-09-04
    Print ISSN: 0163-1829
    Electronic ISSN: 1095-3795
    Topics: Physics
    Published by American Physical Society
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...