[CP2K:1000] harmonic restraint functional form

Teodoro Laino teodor... at gmail.com
Tue May 6 05:03:55 UTC 2008

Hi Ali,

On 6 May 2008, at 06:57, Ali wrote:

> Dear cp2k users,
> I just wanted to check this to confirm. As far as I can tell the
> functional form for the harmonic restraint within the MOTION% 
you got it right.. the functional form used is this one:

> k(x-x_o)^2

I will add a comment in the input reference regarding the functional  
Thanks for the feedback!


> and NOT (k/2)(x-x_o)^2.
> I am used to seeing the latter in most of functional forms for the
> harmonic potential but I guess the implementation is the former. This
> isn't a complaint but more so a check to make sure that this is true.
> In fact in all the sections (except the FORCEFIELD section where you
> can select the functional form depending on whether you use CHARMM or
> GROMOS), for example when one uses the ddap_constraints, the
> functional form for the harmonic potential is the latter of the above.
> Ali
> >

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