I’m using hybrid style Morse and EAM potential for my simulation which has copper and carbon.
Atom type 1 = Carbon (tool)
Atom type 2 = Copper (workpiece)
Initially I used potential as follows-:
Morse and EAM potentials
pair_style hybrid morse 6.9095 eam
pair_coeff 2 2 eam Cu_u3.eam (and Cu_u6.eam)
pair_coeff 1 1 morse 0.00000001 2.555 2.522
pair_coeff 1 2 morse 0.1063 1.8071 2.3386
After few timesteps I got an error ‘Invoked pair single on pair style none’… then I read the mannual and it seems that there was some undefined pair style, which I don’t think as I have defined all the potetails as shown above… I don’t know the reason??
Also, there’s only difference of parameters populated after row three, between Cu_u3.eam and Cu_u6.eam, which one should be used in my case and does it effects on how LAMMPS calculates the properties?
None of them worked, so I used following option of using eam/alloy. As Cu_mishin1.eam.alloy only has 1 tyype of atom that is Copper. Can I use this file for my case? Also, what the difference between Cu_mishin1.eam.alloy and Cu_zhou.eam.alloy?
Morse and EAM potentials
pair_style hybrid morse 6.9095 eam/alloy
pair_coeff * * eam/alloy Cu_mishin1.eam.alloy NULL Cu
pair_coeff 1 1 morse 0.00000001 2.555 2.522
pair_coeff 1 2 morse 0.1063 1.8071 2.3386
Thanks
Mayank
Re: pair single error - you need to figure out what command
in your script is invoking pair single - I don't think it is
the pairwise computations themselves, unless you are using
a really old version of LAMMPS.
Re: different EAM files - look at the header line of the files -
they give a citation - read the paper to find out who developed
that potential and what it's good for.
Steve
I have figured out few things such as “dump 10 custom 4000 dump.st tag type c_str[1] c_str[2] c_str[3] c_str[4] c_str[5] c_str[6]” command is invoking pair single, when I’m using Cu_u3.eam file. But this is not the case when I use Cu_mishin1.eam.alloy. Also, i’m using Oct 2007 Lammps, is this could be the reason for this? Should i use the latest LAMMPS?
Also I read the papers by Zhou and Mishin for EAM potential, the eam.alloy files are normalized potentials and can be used for any combination of 16 metals. The potential are generic two body potentials developed by fitting of cut off as an intrincis part of potential for different elements. Can I use this for only Copper atoms, as these files are genralized? Also, Cu_u3.eam and Cu_u6.eam files does not have citation.
Thanks
Mayank
Yes, use the latest version of LAMMPS. If any of your
problems remain, then ask a question. You can use an
alloy EAM file for just a single element. Whether that
is a good thing to do, depends on the potential. The paper
or the authors are your best bet for that.
Steve