You have 1mol of your system. conversition factor for kJ/(mol*nm) -> pN is approx 1.661 Am 29.06.2012 10:33, schrieb gmx-users-request at gromacs.org: > Dear Gmx Users, > > How to recalculate the force constant from the harmonic potential: 1 > [pN/A] into [kJ/mol nm2] ? Where is the [mol] here? > > Thanks, > > Steven