RESP
Clicked A Few Times
11:45:23 AM PDT - Thu, Oct 25th 2012
Greeting,
I have a question regarding the RESP charges.
I built a polymer. I increased the carbon atoms each time by one ..I got a model now made of 9 atoms
I did a geomtry optimization along with RESP charges fitting.
I know that I should stop increasing atoms when the internal segments charges are constants is this right? my question is the internal means all atoms without the two at the ends? if I want to write a topology for this brand new residue to get the charges by averaging them is there is any tutorial for that

Thank you for you help,
Spring

Clicked A Few Times
9:00:16 AM PST - Wed, Feb 13th 2013
My recommendation would be to divide the polymer into managable segments (3 to 5 carbon atoms in the chain) and perform a series of RESP calculations with different constraints, until you find a set of charges that with constraints applied is not too much different from unconstrained charges. In this way you will find charges that maintain strict charge neutrality for the individual segments, without this being a significant deviation from unconstrained RESP charges.
Done this way, the RESP procedure will do the averaging for you.


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