Re: [ESPResSo] deleting bonds

[Axel Arnold]

On Wednesday 29 September 2010 03:20:51 Mikheil Azatov wrote:
> Hi espresso users!
>
> In my simulation I need to delete bond between two particles depending on
> some conditions. I learned before what to do to add bonds between
> particles. Now I need to remove the bond for some conditions.Has anyone
> ever had to do that ? I was wondering if there's a way to modify espresso
> files to do that?

Hi,

the routine local_change_bond in particle_data.c can both add and delete a 
bond. However, note that a bond is always attached to a particle. That is, 
assume there is a bond between particles 3 and 5. If you added the bond to 
particle 3, then only particle 3 carries the information that those two 
particles are bonded. If you want to delete the bond, you need to delete it 
from particle 3. That is, you need:

int x[] = {type, 5};
local_change_bond(3, x, 1);

However, there is no problem if the bond doesn't exist; therefore you can 
simply delete both possible bonds, that is, also call:

int x[] = {type, 3};
local_change_bond(5, x, 1);

Many regards,
Axel

-- 
JP Dr. Axel Arnold Tel: +49 711 685 67609
ICP, Universität Stuttgart      Email: address@hidden
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70569 Stuttgart, Germany