Re: [ESPResSo-users] Triple Cos term formula for Dihedral potential

[Axel Arnold]

Hi,

the better option is to copy the relevant code for the dihedral interaction, 
and make a second one with a different name, e.g. dihedral3cos. As for the 
implementation, best simply copy the dihedral.h and replace there the force 
and energy formulas, and of course the names. You then just need to modify 
interaction_data.[ch], energy.h, force.h and pressure.h to add  the glue code. 
You can basically just copy the dihedral code, and have to find a constant in 
interaction_data.h (BONDED_IA_DIHEDRAL3COS).

Many regards,
Axel

On Thursday 26 May 2011 08:47:19 Muhammad Anwar wrote:
> Hello,
> Dear Users,
> I want to use triple cos term dihedral potential in my simulation, which is
> V = 0.5 *( K1 * (1 - cos(phi) + K2 * (1 - cos(2*phi) + K3 * (1 -
> cos(3phi) ).. Can anybody give any suggestion, how can i amend the given
> dihedral potential to use this potential? There may be two
> possibilities, one in which i just put the tcl command like this
> 
> inter 3 dihedral 1 1 0
> and change the dihedral file according to my need by putting the
> different values of K and phi, but this would be more specific for only
> one case. The second option may be i write separate header file for it
> and use it. If i use first option i will just change the fac value by
> adding new terms for force and energy. Is it ok? or should i write new
> code for it, if yes how can i write and add? Please guide me?
> Thanks
> 
> Best Regards,
> Muhammad Anwar
> 

-- 
Axel Arnold
Martha-Schmidtmann-Str. 7       Phone:  +49-173-8706659
D-70374 Stuttgart               E-Mail: address@hidden