<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:'times new roman', 'new york', times, serif;font-size:12pt"><div>Hi,</div><div><br></div><div> I have a molecule consisting of 4 sites which have fixed relative positions interacting only through LJ and coulomb interaction. I was wondering how can I do MD simulation in GROMACS keeping the geometry unchanged . Is just putting constraints along all the possible distances and using LINCS good enough for maintaining the geometry ? Or , Does one need to also make sure the angles are also unchanged but I am not sure how to do that ? I was wondering what will be an optimum ways of dealing with such a 4-site system. I guess, Settle can not be used for such a 4-site system.</div><div><br></div><div>Thanks</div><div>Sanku</div><div style="position:fixed"></div>
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