[DFTB-Plus-User] Nose-Hoover,CouplingStrength

[Ben Hourahine]

Hello Again,

The results are not supposed to be strongly sensitive to the coupling 
strength,
but as with all of these things, testing it is the best thing to do. I 
would suggest
the higher frequency is probably the better initial choice.

Regards

Ben

On 12/11/12 14:44, Hu Shuanglin wrote:
> Dear all,
>
> Sorry maybe the questions below is not subjective to DFTB, but to MD. 
> It is related with the choice of coupling strength.
> If the system is a molecule on an oxide surface, which scale should 
> one choose for the coupling strength, the frequency of the molecule, 
> e.g. 3000cm-1, or the frequency of the substrate, e.g. 1000cm-1?
> It is said the choice of mass may be not no critical in the paper, but 
> if one choose the coupling on the scale of 3000cm-1, does it mean the 
> thermostat couple stronger with the small molecule but not the substrate?
> Normally, there are much more atoms in the substrate, but the 
> interesting part would be the interaction of the small molecule with 
> surface, is the choice of coupling strength affect the equilibrium 
> efficiency, or even the configurations? If it affects, how does it 
> play with the results?
> Thank you!
>
> Best Regards,
> Shuanglin Hu
>
>    --
> Department of Chemistry - The Angstrom Laboratory,
>    Uppsala University,
>    Box 538, SE 751 21
>    Uppsala, Sweden
>
> On Mon, Nov 12, 2012 at 11:11 AM, Ben Hourahine 
> <benjamin.hourahine at strath.ac.uk 
> <mailto:benjamin.hourahine at strath.ac.uk>> wrote:
>
>     Dear Wang,
>
>     Martyna et al. J. Chem. Phys. 97, 2635 (1992) discusses the choice,
>     suggesting it should be on a scale similar
>     to the vibrational modes of the system.
>
>     Regards
>
>     Ben
>
>
>
>     On 12/11/12 06:57, 刘雷 wrote:
>     > Dear All:
>     >   I am a new user of DFTB+. I want to calculate
>     finite-temperature structures of SiC using Molecular dynamics with
>     NVT.
>     > The thermostat I want to use is NoseHoover{},but I don't
>     understand the meaning of the parameter "CouplingStrength".
>     > What value should I set for this "CouplingStrength" ?
>     >
>     > Wang Dandan
>     > Graduate Student
>     > Changchun Institute of Optics, Fine Mechanics and Physics,
>     Chinese Academy of Sciences,
>     >
>     >
>     >
>     >
>     >
>
>
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-- 
      Dr. B. Hourahine, SUPA, Department of Physics,
    University of Strathclyde, John Anderson Building,
           107 Rottenrow, Glasgow G4 0NG, UK.
     +44 141 548 2325, benjamin.hourahine at strath.ac.uk
    The University of Strathclyde is a charitable body,
registered in Scotland, with registration number SC015263

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