Pair_style hybrid

Dear lammps users,
I am modeling a quaternary system. I am using two different pair styles, Morse and coul/wolf for the interactions. What is the difference if I am giving the interactions separately like in (1) or giving using hybrid command as in (2)

pair_style morse 6.0

In the first one each pair_style command overwrites earlier ones. The second one allows for using different pair_styles alongside.


Thank you Michal. But I am using single pairstyle for each pair. For some pairs only Morse and for others, only coul like that. So how come overwritten will happen?

This is the way LAMMPS is designed – pair_style is defined for an entire system and if you want to utilize different potentials at once you have to use pair_style hybrid.


Thank you Michal. I have few more doubts. If I am using a hybrid potential, how to check the reliability of the potential for that system? Other than it’s lattice parameter and bulk modulus, do we need to check any other things?
I have got results for lattice parameter and bulk modulus comparable with the reported values (@0K) But when I am bringing the system to 300K, the potential fails. How to fix this?

Thanking you,

You should search literature for similar systems and check what potentials were used. For questions about potential validation you should contact a local advisor, since this mailing list is for providing support with LAMMPS issues.

What do you mean by “potential fails”? If your system behaves abnormally, it may be caused by wrong potentials, but also by too high timestep or bad initial geometry.