Hello lammps-users,
I'm new to lammps and MD.
I want to simulate a SAM monolayer on an infinite gold surface in water.
I would like to use the hybrid pair style because I want to describe
the interactions between gold atoms with the ReaxFF and the all other
interactions with charmm.
Is it possible?
How can I describe the bond between an atom involved in the reaxFF
with an atom involved in the charmm FF ( for example the S-Au
interaction)?
Thank you,
Piero
Hello lammps-users,
I'm new to lammps and MD.I want to simulate a SAM monolayer on an infinite gold surface in water.
I would like to use the hybrid pair style because I want to describe
the interactions between gold atoms with the ReaxFF and the all other
interactions with charmm.Is it possible?
technically, yes, but in practice you have to
first check if there is a suitable parametrization
and i doubt there is one.
i've done DFT calculations in the past of such
a system and finding parameters for the Au-Au-S-C
interactions is far from trivial.
How can I describe the bond between an atom involved in the reaxFF
with an atom involved in the charmm FF ( for example the S-Au
interaction)?
you will have to choose how to partition the system
between using the two different force fields.
the important question with this kind of setups
always is: what is it that you want to learn from
the simulation? and: is the effort and level of detail
really needed? or the other way around: can this
be represented by the force fields that you mention
at all? you should find answers to these questions
before wondering about what is technically possible.
cheers,
axel.
I thought hybrid simulations with reaxc or reax are not possible yet?
robert
I thought hybrid simulations with reaxc or reax are not possible yet?
yes, you are correct. my bad.
axel.
It would only be modestly hard to amend
the 2 ReaxFF in LAMMPS to make
them compatible with pair_hybrid. It
just hasn't been done yet.
Also, the ReaxFF people would say
its a universal force field, so you should
do your whole system with it and there
is no need to even consider another ff 
Steve