I am using current release of LAMMPS for NEB calculations.
I am interested in calculation of the energy barrier associated with hopping of a rigid CO2 molecule through a small pore window in a rigid porous structure.
Although, I have used proper “fix rigid” command for my NEB molecule, I have noticed that atomic structure of CO2 is changing during the minimization process!
I wonder if anybody has a clue on the cause of this problem. Input script is attached for your consideration.
I am using current release of LAMMPS for NEB calculations.
what does "current" mean? it can change every day. please specify the
exact version as printed.
I am interested in calculation of the energy barrier associated with hopping
of a rigid CO2 molecule through a small pore window in a rigid porous
structure.
hmm... do you think NEB is a good method for that? you only get the
potential energy barrier, but for a process like you describe, this
may not show the whole picture. what would be much more descriptive is
the *free* energy barrier, as that would also include the (likely to
be significant) entropy contributions.
Although, I have used proper “fix rigid” command for my NEB molecule, I have
noticed that atomic structure of CO2 is changing during the minimization
process!
I wonder if anybody has a clue on the cause of this problem. Input script
is attached for your consideration.
the clue is in the documentation:
These fixes are not invoked during energy minimization.
NEB is a minimization technique. Many fixes are not
supported during minimization unless they are documented
to do so. Fix rigid is not. I.e. you also can’t perform
a minimize command on a rigid body.