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
    Coupled molecular dynamics/semiempirical simulation of organic solutes in polar liquids. II. Coumarin 153 in methanol and acetonitrile (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 6834-6842 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this paper we present a coupled molecular dynamics/semiempirical simulation of the solvation of the dye Coumarin 153 (C153) in two solvents, methanol and acetonitrile. In order to account for the solute electronic polarizability we use a semiempirical description to determine the charge distribution of the dye during the simulation. Solute–solvent and solvent–solvent interactions are described by empirical potentials. We examine the structure of the solvation shell, the purely electrostatic part of the solute–solvent interactions, shifts of the absorption and emissions spectra and the solvation dynamics of C153 in both solvents. In contrast with our first study of naphthalene in acetonitrile, the equilibrium simulations show structural changes in the solvation shell when electronic polarizability is included. The inclusion of electronic polarizability also enhances solute–solvent electrostatic interactions. Therefore, an increase of absorption and emission redshifts is observed compared to simulations with a nonpolarizable solute. While the computed absorption shift is in excellent agreement with experimental data, the emission shift calculations fail. Possible reasons for this failure are discussed. The solvation dynamics shows a considerable slowing down compared to the nonpolarizable solute. Nonetheless, linear response is still valid in these systems. Some differences with the continuum model of solvation are pointed out. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1351876
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Coupled molecular dynamics/semiempirical simulation of organic solutes in polar liquids. I. Naphthalene in acetonitrile (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 6824-6833 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this paper we present coupled quantum mechanical/molecular dynamics simulations on the solvation of naphthalene in acetonitrile. A semiempirical treatment is introduced into classical molecular dynamics simulations to deal with the electronic polarizability of the solute. We study the structure of the solvation shell, the features of the electrostatic intermolecular interactions, the dynamics of solute and solvent molecules and the spectral shifts of the solute. For this particular system it is found that the influence of induced electrostatic interaction on the structure of the solvation shell is negligible. On the other hand, net induced dipolar contributions arise in the electrostatic interactions, in spite of the fact that the electric field is found to be inhomogeneous at the scale of the solute molecule. These induced dipolar interactions enhance the calculated absorption and emission shifts and contribute up to 40% to the electrostatic spectral shifts. They also modify or even dominate the fluctuations of the solute–solvent interaction and thus the solvation response. Both shifts and solvation dynamics are discussed in terms of dipole and quadrupole jumps. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1351875
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A falling head permeameter for the measurement of the hydraulic conductivity of granular solids (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 3942-3946 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A falling head permeameter is described in which pairs of infrared emitters and detectors on a sight tube are used to measure the flow rate associated with the passage of water through a granular solid under the action of a diminishing pressure head. An equation relating pressure head to elapsed time is derived from which permeability may be calculated. In order to verify the accuracy and sensitivity of the instrument, permeability measurements carried out on a graded quartz sand are compared to those obtained by the more conventional constant head measurement. Excellent agreement is obtained between the permeability values obtained using both measurement methods. Experimental results are also reported for the measurement of the permeability of a range of sieved sand fractions. The falling head permeameter described here is particularly suitable for the measurement of the hydraulic conductivity of granular solids such as sands and soils through which a high flow rate may be expected. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1310349
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Grain boundary ridge on sintered bonds between ice crystals (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 5782-5785 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Well-sintered snow examined in a scanning electron microscope revealed a newly observed morphological structure that protrudes into the pore space along ice grain boundaries. We have termed this a "grain boundary ridge." Grain boundary diffusion is a sintering process that occurs at the interface of two crystals, whereby mass migrates from the center of the contact to the surface of the bond. Since mass tends to sublimate from sharp features toward smaller curvature surfaces through vapor diffusion, a ridge developed by grain boundary diffusion will readily sacrifice mass to the surrounding ice surfaces. A mass balance between vapor and grain boundary diffusion based on the observed geometry is considered. This analysis indicates grain boundary diffusion may play a far more significant role than generally acknowledged. While this study was restricted to ice, it may have implications for other crystalline materials. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1410889
    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...