salah boulf... at googlemail.com
Wed Oct 8 10:36:04 UTC 2008

first, thank you for the two answers.

>why should we consider MEAM and what are the differences
>in the energy expression to EAM
Well, If you allow me a bit of verbosity,
MEAM is an extension of the EAM to include angular dependencies in the
electron densities to give angular forces which are very necessary to
reproduce the behavior of non-fcc materials. The general formulation
of MEAM maintains the computational simplicity of the EAM and can be
applied to wide range of elements as well as to a large number of
multi-components systems and even the melt (Baskes et al PRB 65 /
024209 / 2001). The MEAM accounts for directional bonding and bond-
bending because the first nearest neighbor 1NN and the second 2NN are
considered. So the behavior along transformation paths involving a
change in the local coordination is well captured. This is just to
mention a few aspects of the MEAM.

> do you have a special need for MEAM in cp2k?
> there is a MEAM implementation in the LAMMPS MD
> code for example, which seems to me in general
> better suited for this kind of simulation setups
> as cp2k. unless one needs specific features that
> are only available in cp2k, that is...
In LAMMPS, the NPT integrator has not been yet enhanced to allow for
shape changes due to off-diagonal pressure tensor components (no NsT
or Parinello-Rahman ensemble like in cp2k, no NPT_F).
I need MEAM potential with flexible NPT to not impose any bias to my
simulations and more important to be able to reverse MD simulations.

Hope I've convinced somebody to have a look at the MEAM question.



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