[gmx-users] PLUMED-GROMACS force constant, angle unit

tarak karmakar tarak20489 at gmail.com
Tue Aug 14 14:27:50 CEST 2012

Dear All,

In the manual I see the unit of the k{theta} is kJ/mol/rad^2. But
Neale et al in Chemical Physics Letters 460 (2008) 375–381 has applied
the harmonic restraints with a force constant of
0.0364 kcal/mol/deg^2 for the phi and psi dihedral angle of alanine
dipeptide. If I convert it into KJ/mol/rad^2 then its coming out to be
around 500.4 KJ/mol/rad^2.

Can I safely use this large force constant value to do US for the same system?
I am utilizing the PLUMED software patched with gromacs. Should I
specify the angle in degree unit in plumed input file, since in
GROMACS  ffbonded.itp file angles are defined in degree unit ?


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