[lammps-users] ABOUT THE EAM POTENTIAL FOR IRON

Dear lammps users,

I am working in carbon nanotube formation from a cluster of carbon atoms and iron atoms.For iron atom interaction i used the EAM potential as given below,

pair_style eam
pair_coeff * * /home/labuser/lammps/potentials/Fe_mm.eam.fs

But it is showing some error as “INVALID MASS VALUE”.I had given the mass for iron is 55.58.Is there any wrong with this or is there any wrong with the potential data file for iron? Now i am struggling with this. Please reply me

regards,
safron

Dear lammps users,

I am working in carbon nanotube formation from a cluster of carbon atoms and
iron atoms.For iron atom interaction i used the EAM potential as given
below,

pair_style eam
pair_coeff * * /home/labuser/lammps/potentials/Fe_mm.eam.fs

But it is showing some error as "INVALID MASS VALUE".I had given the mass
for iron is 55.58.Is there any wrong with this or is there any wrong with
the potential data file for iron? Now i am struggling with this. Please

no, the problem exists between your chair and your computer!
the readme in the potential directory says:

eam embedded atom method (EAM) single element, DYNAMO funcfl format
eam.alloy EAM multi-element alloy, DYNAMO setfl format
eam.fs Finnis-Sinclair EAM format (single element or alloy)

and the documentation to the EAM pair styles says:

IMPORTANT NOTE: The eam style reads single-element EAM potentials in
the DYNAMO funcfl format. Either single element or alloy systems can
be modeled using multiple funcfl files and style eam. For the alloy
case LAMMPS mixes the single-element potentials to produce alloy
potentials, the same way that DYNAMO does. Alternatively, a single
DYNAMO setfl file or Finnis/Sinclair EAM file can be used by LAMMPS to
model alloy systems by invoking the eam/alloy or eam/cd or eam/fs
styles as described below. These files require no mixing since they
specify alloy interactions explicitly.

read this again and carefully and enlightenment will come to you.

cheers,
    axel.

In other words you can only use *.fs files with pair_style eam/fs.

Steve