Dear all,
From the user guid book, I learned that for a dihedral style of charmm, a dihedral_coeff command like this is required:
dihedral_coeff 1 120. 1 60. 0.5
But, the charmm dihedral style sometimes uses multilines to specify dihedral coeffs, like
ON5 CN6 CN6 ON5 0.3 3 0.0
ON5 CN6 CN6 ON5 -1.93 1 0.0
My question is how to write dihedral_coeff in an input file in this case?
Does the following command right?
dihedral_coeff 1 0.3 3 0.0 1.
dihedral_coeff 1 -1.93 1 0.0 1.
I could not find any instructions in the user guide book.
I would be grateful if someone could give me some advice.
Thanks you.
Dear all,
From the user guid book, I learned that for a dihedral style of charmm, a dihedral_coeff command like this is required:
dihedral_coeff 1 120. 1 60. 0.5
But, the charmm dihedral style sometimes uses multilines to specify dihedral coeffs, like
ON5 CN6 CN6 ON5 0.3 3 0.0
ON5 CN6 CN6 ON5 -1.93 1 0.0
My question is how to write dihedral_coeff in an input file in this case?
Does the following command right?
no. the second would override the first.
dihedral_coeff 1 0.3 3 0.0 1.
dihedral_coeff 1 -1.93 1 0.0 1.
I could not find any instructions in the user guide book.
have you looked at the ch2lmp tool in the tools section and
specifically the example? from that you can easily deduce that
you have to enter both parameters sets as two dihedral types and
then assign each of them to the same sequence of atoms.
I don't know what CHARMM means when you specify
two sets of coeffs for the same atoms. I guess you
would need to either a) find a way to combine them
into one set of coeffs for a LAMMPS dihedral
style, or b) list the dihedral twice in the LAMMPS data
file, with 2 different types (same 4 atoms). Then
you could have one dihedral_coeff command for each
type and list both sets of coeffs. The dihedral would
just be computed twice.
Not sure if the ch2lmp tool will do this for you if you
specify the CHARMM input appropriately.