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Re: [ESPResSo] a specific interaction rule between particles
From: |
Torsten Stuehn |
Subject: |
Re: [ESPResSo] a specific interaction rule between particles |
Date: |
Tue, 17 Aug 2010 11:47:39 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100317 SUSE/3.0.4-2.3 Thunderbird/3.0.4 |
Dear Narges,
you could also have a look at the implementation of the angledist potiential
which you can find in angledist.h (this potential is not very well tested
though).
This potential is a "three body + 1 constraint" potential. It calculates a
standard angular potential between 3 particles and additionally varies the
bond angle parameters depending on the distance of the particles to a
constraint wall.
Best regards,
Torsten
On 08/17/2010 11:17 AM, Axel Arnold wrote:
> On Tuesday 17 August 2010 09:54:01 address@hidden wrote:
>> Dear all,
>> I have a problem in which some particles have a
>> specific interaction rule. Their interaction energy depends on their
>> distance from each other as well as their distance from a surface. So the
>> interaction of two particles depends on three parameters: particles
>> distance from each other
>> and distance of each of them from the
>> surface. Particle-particle and particle-surface interactions are both
>> short-range. Is there any way to handle these interactions with Espresso,
>> even by some changes in the source files? for eg. is it possible to change
>> the tabulated interaction to depend on 3 parameters? Some general guides
>> are also very useful!
>
> Hi!
>
> I guess that since you have 3 parameters, it will be rather difficult to
> tabulate the interaction, so there should be some analytic description. In
> this case, the easiest thing is to look at for example the smooth step
> potential, which you can find rather easily by using grep for SMOOTH_STEP and
> looking at steppot.h. You basically need to write a new header file for your
> interaction, and write corresponding code to each of the SMOOTH_STEP #ifdefs.
>
>
> The pair force functions also obtain pointers to both particles, so you can
> simply look at the particle positions, and do what ever you like with them,
> for example adapting your potential.
>
> Many regards,
> Axel
>
--
Dr. Torsten Stühn
MPI für Polymerforschung
Ackermannweg 10
55128 Mainz / Germany
Tel. +49-(0)6131-379268
Fax +49-(0)6131-379100
EMail address@hidden