I would like to attempt to model particle escape from a potential well, i.e to see the time required for the particle to overcome the "activation energy" barrier as a result of brownian motion, from a parabolic potential, for instance. I understand that there are several commands associated with "trapping" particles such as fix_spring / fix_wall/region, in which both harmonic and lj potentials can be used; however, I am not sure whether parameters can be adjusted such that escape from the potential becomes possible?
If the particle is "bonded" to the well with
a spring, it will not be able to escape.
You could create a non-bonded version
of a well by tabulating a potential of
your choice that allows for escape over
a barrier. And use it in a non-bond sense
via the pair_style table command.
Then do a simulation with 2
particles, nail one of them down, and let
the other one move thermally in that potential
until it escapes.
dear <i would put your name here, if you would use it in your e-mail>,
I would like to attempt to model particle escape from a potential well,
i.e to see the time required for the particle to overcome the
"activation energy" barrier as a result of brownian motion, from a
parabolic potential, for instance. I understand that there are several
commands associated with "trapping" particles such as fix_spring /
fix_wall/region, in which both harmonic and lj potentials can be used;
however, I am not sure whether parameters can be adjusted such that
escape from the potential becomes possible?
the lj based wall potentials are applying a LJ potential,
so an escape is possible. for fix spring this is not possible.
another option would be to have one (or more) atom(s)
placed in your system but not time integrated. then you
can have any kind of pair potential between that position
and your particles.
whether trying to model this explicitly to get the time
is a good idea, is a cat of a different color. i suggest
you first review the existing textbook knowledge about
the relation of the height of (free) energy barriers to
the average time to escape. that will probably save
you a lot of time (pun intended).