CHARMM force field

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1

Dear all,

I want to simulate heptan with CHARMM36 force field. I checked the bonded and non-bonded parameters files of this force field.
Heptan has 7 types dihedrals, two dihedrals of them have several parameters:

V(dihedral) = K(1 + cos(n(phi) - delta))

[ dihedraltypes ]
i j k l delta K n

CC32A CC32A CC32A CC32A 0.000000 0.470742 5
CC32A CC32A CC32A CC32A 0.000000 0.395723 4
CC32A CC32A CC32A CC32A 180.000000 0.626554 3
CC32A CC32A CC32A CC32A 0.000000 0.269868 2

The dihedral_style is charmm. How can I choose the parameters and what’s the reason?

Thanks.

2

Dear all,

I want to simulate heptan with CHARMM36 force field. I checked the bonded
and non-bonded parameters files of this force field.
Heptan has 7 types dihedrals, two dihedrals of them have several parameters:

V(dihedral) = K(1 + cos(n(phi) - delta))

[ dihedraltypes ]
i j k l delta
K n
CC32A CC32A CC32A CC32A 0.000000 0.470742 5
CC32A CC32A CC32A CC32A 0.000000 0.395723 4
CC32A CC32A CC32A CC32A 180.000000 0.626554 3
CC32A CC32A CC32A CC32A 0.000000 0.269868 2

The dihedral_style is charmm. How can I choose the parameters and what's the
reason?

it is not clear what you are asking here. please elaborate.

axel.