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DRF: Discrete Reaction Field method (Read 4384 times)
Gerrit-Jan Linker
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DRF: Discrete Reaction Field method
24.07.08 at 23:20:10
 
DRF: Discrete Reaction Field method
 
In the DRF method a reaction field operator is included in the Hamiltonian. The electron feels the reaction field of itself and the other electrons instantaneously.
 
This opposed to ARF, the Average Reaction Field method, in which electrons experience the reaction field on the charge distribution as a whole.
 
Thesis' in which DRF is explained:
Marcel Swart :  
  http://iqc.udg.es/~marcel/eng/index.html
  http://theochem.chem.rug.nl/publications/PDF/ft463.pdf
Lasse Jenssen:  
 http://www.scm.com/Doc/jensen.pdf
 http://theochem.chem.rug.nl/publications/PDF/ft500.pdf
Rob Zijlstra
 http://theochem.chem.rug.nl/publications/PDF/ft426.pdf
Alex de Vries
 http://theochem.chem.rug.nl/publications/PDF/ft267.pdf
Thomas la Cour Jansen: Theoretical Simulations of Nnlinear Spectroscopy in the Liquid Phase.
 
Technical information about the DRF program can be viewed at Marcel Swart's site:
http://iqc.udg.es/~marcel/manuals/drf90/index.html

See also:

DRF90
http://www.oraxcel.com/cgi-bin/yabb2/YaBB.pl?num=1251641181
DRF90: a polarizable force field
http://theochem.chem.rug.nl/publications/PDF/ft434.pdf
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« Last Edit: 08.04.10 at 08:26:00 by Gerrit-Jan Linker »  

Gerrit-Jan Linker
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Re: DRF: Discrete Reaction Field method
Reply #1 - 10.04.09 at 09:30:47
 
DRF: a qualitative description
 
In the DRF method molecules can be described classically or quantum mechanically. Classically described molecules can also be used in molecular mechanical simulations.
 
To describe a molecule classically a representation is built that comprises point charges and polarisabilities at all the atomic centers of the molecule. To determine these point charges the molecule is modeled quantum mechanically in vacuum.
 
The point charges are chosen such that the overall charge and dipole of the molecule is reconstructed. At each atomic center a point charge is placed.
The polarisabilities are also placed at the atomic positions. These atomic polarisabilities are taken from experiments.
 
Having calculated these point charges and polarisabilities a classical representation of the molecule can be made. In DRF these classical described molecules can interact or they can interact with molecules that are quantum mechanically described.  
 
It is important to note that the classically described molecules are not static. They can still respond to the environment through the polarisabilities centered on each atom. This is done through a response function.
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« Last Edit: 11.02.10 at 10:27:52 by Gerrit-Jan Linker »  

Gerrit-Jan Linker
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The Discrete Reaction Field method
Reply #2 - 11.02.10 at 10:28:25
 
The Discrete Reaction Field method
 
The DRF approach uses a polarisable force field which is (apart from the short range repulsion) based on second-order perturbation theory (ensures the correct analytical form of model potentials). Force field parameters are obtained from quantum chemical calculations where possible.
 
Source:
The discrete reaction field approach for calculating solvent effects
Duijnen, P.Th.van, Swart M. and Jensen L.
In: Solvation effects on molecules and biomolecules, S. Canuto, Editor. Springer. p. 39-103
http://theochem.chem.rug.nl/publications/PDF/ft608.pdf
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« Last Edit: 11.02.10 at 10:39:50 by Gerrit-Jan Linker »  

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