[gmx-users] Maximum Force constant for Position Restraints

[Marcelo Depólo]

Thanks Alex. But then, theoretically, is there no limit? All depends on
your system's content, right?

2015-04-21 16:16 GMT-03:00 Alex <nedomacho at gmail.com>:

> Correction: tau/pi on the left for the highest value and 5*tau/pi for the
> 10 x period suggestion above.
>
> On Tue, Apr 21, 2015 at 1:13 PM, Alex <nedomacho at gmail.com> wrote:
>
> > I think this can be estimated from a general physical argument. The
> > absolute max in my opinion should come from
> > 4*pi*tau = sqrt(m/k), where m is the mass of the lightest restrained
> > particle in the system, k is the constant you seek, and tau is the
> > timestep.
> > The coefficient is four because of the Nyquist theorem. I believe GMX
> > tests for high vibrational frequencies according to 20*pi*tau on the left
> > (ten times the period).
> >
> > Hope this helps.
> >
> > Alex
> >
> >
> > On Tue, Apr 21, 2015 at 1:02 PM, Marcelo Depólo <marcelodepolo at gmail.com
> >
> > wrote:
> >
> >> Hi guys!
> >>
> >> Is there a maximum value of Force Constant for Position restraints?
> >> Reading
> >> the Manual I could only find the default and the equation to describe
> it.
> >>
> >> Best,
> >> --
> >> Marcelo Depólo Polêto
> >> Group of Structural Bioinformatics - Center of Biotechnology
> >> Student of MSc Cell and Molecular Biology - UFRGS (Brazil)
> >> B.Sc. Biochemistry - University of Viçosa (Brazil)
> >> --
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> >
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-- 
Marcelo Depólo Polêto
Group of Structural Bioinformatics - Center of Biotechnology
Student of MSc Cell and Molecular Biology - UFRGS (Brazil)
B.Sc. Biochemistry - University of Viçosa (Brazil)