Dear Amber users,
I'm trying to determine the charges for phenylguanidinium.
I normally use the RED servers (and very often multiconfigurational fit)
but the q4md website is still down.
Using RESP and Gaussian with one conformation (minimized structure), I get
too high absolute values for them (up to 1.1 for a carbon atom,
see GdPhenyl_resp.mol2).
It's impossible to parametrize the molecule with those charges, the
equilibrium bond length is 0.06 Å shorter than the reference bond length.
I tried the am1-bcc scheme, also with one conformation and the charges
seem reliable (see GdPhenyl_am1-bcc.mol2). I can parametrize the torsion
with them.
Do I have to use the am1-bcc charges? Are they really reliable? Are there
other options?
Thank you for your advice.
*Jérémie Knoops*
*PhD StudentLaboratory for Chemistry of Novel Materials
<
http://morris.umh.ac.be/default.aspx>*
*University of Mons* <
http://portail.umons.ac.be/en2/>
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Received on Tue Oct 27 2015 - 02:00:03 PDT
