<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>Hi,</div><div> Is there any known issue/problem in running FEP calculations with charm27.ff in gromacs4.5.4 ? I tried running an FEP calculation using charmm27.ff by interpolating A state and B state but it gives error that dihedral terms with multiple values can not be interpolated..One need to write all A and B states in topol.top manully.</div><div>With opls.ff , it does not have any such problem.</div><div>Any idea?</div><div>Thanks</div><div>Sanku</div></div></body></html>