Subject: Buckingham potential for polymers

From: Vemparala Satyavani <[email-masked]>
Date: Sat, 14 Jul 2001 09:27:19 -0500 (CDT)

The Buckingham potential has the form Aexp(-rB)-c/r^6. isn't it true 
that with this potential, when particle come closer than a distance, 
there is actually a huge attractive well? what actually prevents the 
particels to come closer? The repulsion part(aexp(-rB)) cannot actually 
counteract the attractive part at small distances. Combined with 
Coulomb(the attractive part), iam having some pathological conditions in 
the system.

And also what is the best way to get an initial configuration? now iam 
just placing the chains on some lattice in a bigger box( so that they are 
well seperated) and then performing Pivot Monte Carlo on them before i 
Actually do MD. Is there a better way to get initial state? I suspect the 
initial state may be a problem for me.

and finally even if i start at such a state, where the chains are well 
seperated, when MD is performed, there is a huge probability that any of 
the nonbonded atoms might come closer, and iam having similar problems 
irrespective of the size of the box.

what is the best way to avoid the huge attractive well in the potential?

Thanks a lot
Vani