By using the examples provided with lammps:
examples/meam/in.meamc
examples/meam/in.meam
=> Direct run of the example gives TotEng = -636.53122
=> When changing
pair_coeff * * library.meam Si C SiC.meam Si C
to
pair_coeff * * library.meam C Si SiC.meam Si C
the run gives TotEng = -451.10229
==> The order after library.meam seems to matter.
Version of lammps used: “22 Feb 2018”
Compiled package: MEAMC or MEAM only
Julien
By using the examples provided with lammps:
examples/meam/in.meamc
examples/meam/in.meam=> Direct run of the example gives TotEng = -636.53122
=> When changing
pair_coeff * * library.meam Si C SiC.meam Si C
to
pair_coeff * * library.meam C Si SiC.meam Si C
the run gives TotEng = -451.10229
==> The order after library.meam seems to matter.
Version of lammps used: "22 Feb 2018"
Compiled package: MEAMC or MEAM only
julien,
you must not do this unless you use NULL for the second file name or the
second file has only global settings.
SiC.meam has the following contents:
# DATE: 2007-06-11 CONTRIBUTOR: Greg Wagner, [email protected]... CITATION:
Unknown
lattce(1,2) = 'dia'
Ec(1,2) = 6.4325
alpha(1,2) = 4.37
re(1,2) = 1.8878
rho0(2) = 2.25
rc = 4.0
delr = 0.1
Cmax(1,2,1) = 4.0
Cmax(1,2,2) = 4.0
Cmax(2,2,1) = 4.0
Cmax(1,1,2) = 4.0
the "1" and "2" in lattce, Ec, alpha, re, rho0, and Cmax are references to
the extracted elements from library.meam, so if you switch "Si" and "C",
you also will have to switch the "2" for rho0 to "1" in SiC.meam.
thus there is no problem in LAMMPS.
axel.
Ah of course! That wasn’t too thoughtful from my side…
Maybe a small precision in the documentation?
Something like:
“The Si and C arguments (between the file names) are the two elements for which info will be extracted from the library file, and map atom type listed in the sic.meam file.”
Thanks for the time spent!
Julien
[...]
you must not do this unless you use NULL for the second file name or the
second file has only global settings.SiC.meam has the following contents:
# DATE: 2007-06-11 CONTRIBUTOR: Greg Wagner, [email protected]... CITATION:
Unknown
lattce(1,2) = 'dia'
Ec(1,2) = 6.4325
alpha(1,2) = 4.37
re(1,2) = 1.8878
rho0(2) = 2.25
rc = 4.0
delr = 0.1
Cmax(1,2,1) = 4.0
Cmax(1,2,2) = 4.0
Cmax(2,2,1) = 4.0
Cmax(1,1,2) = 4.0the "1" and "2" in lattce, Ec, alpha, re, rho0, and Cmax are references to
the extracted elements from library.meam, so if you switch "Si" and "C",
you also will have to switch the "2" for rho0 to "1" in SiC.meam.thus there is no problem in LAMMPS.
Ah of course! That wasn't too thoughtful from my side...
Maybe a small precision in the documentation?
Something like:
"The Si and C arguments (between the file names) are the two elements for
which info will be extracted from the library file, and map atom type
listed in the sic.meam file."
please see the following change to the documentation, that will explain
this (IMO) a bit more precisely.
axel.
ah yes, great idea to add the information in this section!
Julien
I’ll also add a NOTE higher up in the doc file to warn about this issue. It confused me at first!
Steve