How to connect neighboring molecules with Hookean spring

Dear lammps-users

I am looking at a paper about condensation on a surface with Molecular Dynamics Simulations. The name of paper is “On the onset of surface condensation: formation and transition mechanisms of condensation mode”(S Qiang et al Scientific Reports 2016). In this paper, the method about surface wall contain some sentences that “The semi-infinite solid wall at the bottom end is represented by three layers of solid molecules forming a (111) plane of a face-centered cubic lattice with the lattice constant σs = 0.814σ. Neighboring solid molecules are connected by Hookean springs with the constant k = 3249.1 εσ−243.” And can lammps do the action that neighboring solid molecules are connected by Hookean springs? Which command should I use if lammps can do that? Fix spring ? or pair_style gran/hooke command ? Thank you for your help !

Dear lammps-users

    I am looking at a paper about condensation on a surface with Molecular
Dynamics Simulations. The name of paper is “On the onset of surface
condensation: formation and transition mechanisms of condensation mode”(S
Qiang et al Scientific Reports 2016). In this paper, the method about
surface wall contain some sentences that “The semi-infinite solid wall at
the bottom end is represented by three layers of solid molecules forming a
(111) plane of a face-centered cubic lattice with the lattice constant σs =
0.814σ. Neighboring solid molecules are connected by Hookean springs with
the constant k = 3249.1 εσ−243.” And can lammps do the action that
neighboring solid molecules are connected by Hookean springs? Which command
should I use if lammps can do that? Fix spring ? or pair_style gran/hooke
command ? Thank you for your help !

"Hookean spring" -> "Hooke's law" -> "Harmonic spring"

there are different ways to have harmonic spring interactions.

it is not clear from your description, how exactly the spring forces
are applied (e.g. whether to the whole molecule, or just a single atom
in the center).
it also is not clear, whether this was done with LAMMPS or some other
MD code. in the latter case, i suggest you first look up for that code
how this is realized or contact the authors of the paper for details.

in LAMMPS, i would realize this kind of "tethered" molecules using fix
spring/chunk, using compute chunk/atom molecule to partition the
atoms, which is not quite the same, but in my personal opinion a more
realistic model, compared to augmenting the inter-molecule non-bonded
interactions with an additional harmonic potential.

axel.