Dear LAMMPS users,
Hello. I would like for a clarification on special_bonds command. I understand that special_bonds only applies to non-bonded interactions, and not bonded terms. If this is the case, then I was curious if you could inform me the first of the three weighting coefficients as the input argument for special_bonds such as
special_bonds 0.0 1.0 1.0
If special_bonds only applies to non-bonded interactions, then I was curious if you could inform me the role of the first weighting coefficients which determines the weight of the LJ contributions to the 1-2 pairwise interactions. Is 1-2 pairwise interaction same as the bonded interaction? Thank you.
Sincerely,
Masato Koizumi
Dear LAMMPS users,
Hello. I would like for a clarification on special_bonds command. I
understand that special_bonds only applies to non-bonded interactions, and
not bonded terms. If this is the case, then I was curious if you could
inform me the first of the three weighting coefficients as the input
argument for special_bonds such as
special_bonds 0.0 1.0 1.0
If special_bonds only applies to non-bonded interactions, then I was curious
if you could inform me the role of the first weighting coefficients which
determines the weight of the LJ contributions to the 1-2 pairwise
interactions. Is 1-2 pairwise interaction same as the bonded interaction?
please note, that this is something that you should look up in an MD
text book in the section about force fields. in LAMMPS these are
called "special bonds"; elsewhere these interactions may also be
called "exclusions".
these scaling factors apply to non-bonded interactions, that *also*
are part of the bond topology.
so if two atoms have a bond between them, the first special_bonds
scaling factor applies, i.e. typically both coulomb and lj
contributions are completely excluded (factor = 0.0).
if two atoms are related through two bonds that share one atom (i.e.
typically have an angle potential assigned), but do *not* have a bond
(e.g. the two hydrogen atoms in a water molecule), the 1-3 scaling
term applies. same for dihedrals and 1-4 factors.
axel.