[gmx-users] Re: who can help me with the force-field?

[xiao shijun]

   Mark wrote:
       >  xiao shijun wrote:
>> Hi everyone,
>>     Recently, I met a problem on the force-field. I am doing something
>> on the calcium carbonate, and want to simulation it with gromacs.
>> The shell model for oxygen has been emploied in my system. When I
>> considered the non-boned potential associated with interactions between
>> atoms
>> in the same CO3 group, I only need to take O-O buckingham interaction
>> into account, but any electric interaction. How could I realize that in
>> my .top file.
>>     First, I tried to use [pairs] to eliminate electric interaction, but
>> I can't add the buckingham interaction of O-O because there is no
>> buckingham
>> options for LJC14. I want to know if anyone of you have such the
>> experience. Thanks!!

       >Usually you would not define a nonbonded interaction for atoms that
are
       >so close together, since their interaction should be able to be
modelled
       >adequately with the C-O bond and O-C-O angle (and perhaps with
CHARMM,
       >an interaction harmonic the O-O distance as a Urey-Bradley term).

   Thanks for Mark's suggestion. But I want to reproduce the simulation from
the other paper,
 The paper describe the force-field that O-O nonbonded interaction in the
same carbonate should be considered.
 In addition to that, I can't use buckingham potential in [pairs], even
choose funct = 2. I am wondering
 if I want to describe 1-4 interaction by Buckingham, what could I do?

   BEST

 Shijun XIAO
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