Dear Developers,
I have a question concerning the use of the collision-based bonds. I want to set up a system where particles have a tendency to aggregate, potentially using the dynamic bonding, but are also subjected to strains which cause these bonds to break at some later time, when the particle centers are sufficiently far apart.
Going through the mailing list only revealed a single question under "Bond Breaking in Polymer Networks - United Atom Force Fields" but at the time (2012) this kind of simulation was not possible in ESPResSo, and Axel suggested periodically returning to the (then) Tcl level to break bonds by hand.
Looking through the documentation, it is not clear whether any of what I would like to do is possible now. Both
"bind_centers" and "bind_at_point_of_collision" harmonic bonds do not appear breakable, with the latter having an additional complexity due to the virtual sites that are created.
There is a small comment on tabulated bonds breaking outside of their interaction range, but I think this is not what I am looking for, and more a warning to ensure that particles stay inside the range.
So in summary, what I want to do is:
If particles are say 1 in diameter, there would be a pure repulsion up
to 1 and a small, but deep attractive well between 1 and 1.05 separation. When the particles are within this well, centered at say 1.025 separation, I want to prevent them from rolling over each other using the "bind_at_point_of_collision" method, but I want the bond to break again when I pull the particles more than 1.05 apart and the particles to be able to bind somewhere else.
I hope you can help.
Best Wishes,
Joost