Can LAMMPS model radiation

Can LAMMPS model radiation damage in materials? I’ve looked at some of the documentation and it seems possible. If not, is simulating the addition of energy the next best thing?

Jake

Modeling radiation is a broad term and as such isn’t necessarily clear.

If you are looking to model the impact on the structure of lower energy radiation (< 1 KeV), it is best to turn to some sort of Kinetic Monte Carlo approach such as that listed here: https://arxiv.org/pdf/1504.02537.pdf

If you are looking for particle-particle interactions the scale and modeling methods of MD is not going to be satisfactory.

Cheers!
Collin

Typical are so-called “cascade” simulations where you assign a very high kinetic to a single atom (PKA). You can search through the mailing list archives and should find discussions on the subject and possibly some usable input fragments for inspiration.
Axel.

So would it be a better idea to look for a software that is more suitable to modeling high energy photons if that’s what I need?

Since LAMMPS does classical MD, there is no direct modeling of the photon-atom interaction. However, you can couple a classic system to a continuum model of an electron gas with fix ttm and fix ttm/mod.

It really all depends on the physics you want to model and the length and time scales. Not every combination is feasible and not everything an be done with the same software.

A good starting point is usually a thorough survey of the published literature on similar studies. That should give you a sense of what can be done and what methods, models and tools people are using.

Axel.

LAMMPS can model the collision cascades due to energetic primary knock-on atoms (PKA). PFA a script doing this for W PKA at 5 keV. You might want to change the PKA i.d. in this file since that depends on the number of processors you are using.

If you just want to model the effect of an energy being dumped in the free electrons of a metal, using the two-temperature model is advisable (https://lammps.sandia.gov/doc/fix_ttm.html).

Hope this helps.
Manoj

in.pka_5keV_W (1.66 KB)