Dear QE users,
I am actually working on a system with C and N atoms. Checking the
convergence of the total energy for finding the optimal values for the
cutoffs (i.e. DE ~ 1mRy), I found that, despite in the atomic case the
suggested values (for example the wfc cutoff are ~ 46 Ry for both) are
Dear Aldo,
very worthwhile work! Also very hard (pun intended) - pseudopotential
generation is not an easy task. In particular, you can make things
softer, but less accurate, and that's not one wants. Also, being at a
cutoff that converges the total energy is not superinteresting - we
typ
Dear Nicola,
thanks for your reply. I mentioned the energy criteria for convergence
as the simplest one to verify.
Regarding the pseudos you mentioned (PBE), those available at the
materialscloud portal, I have checked them either in the atomic case and
for a simple system of interest. In th
On Thu, Apr 2, 2020 at 1:15 PM Aldo Ugolotti
wrote:
> there were problems with tests with more electrons (e.g. 2s2 2p3 for C)
negative ions are unbound in "plain" DFT: it's a known problem, independent
upon pseudopotentials
Paolo
--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fi
Dear Paolo,
that settles at least part of my question; thanks for the clarification.
Bests regards,
--
Aldo Ugolotti, Ph.D.
Post-doc fellow
Materials Science Dept. U5,
Università degli Studi di Milano-Bicocca
via Cozzi 55,
20125 Milano (MI)
Italy
e-mail: a.ugolo...@campus.unimib.it
On 02/04
On 02/04/2020 18:16, Aldo Ugolotti wrote:
Dear Nicola,
thanks for your reply. I mentioned the energy criteria for convergence
as the simplest one to verify.
Dear Aldo,
indeed, it is simple, but also it is not relevant, so there aren't many
conclusions that can be drawn from it.
Regard
Dear Nicola,
I share with you the perplexity about the unusual values for the
cutoffs, that's why I wished to understand the origin of it and whether
it could be improved or fixed (other than just setting such cutoff and
keep going). About checking the pseudo versus the total energy, it might
Ciao Aldo,
a meaningful/useful test would be this - take a simple case of a CN
system - it can be as simple as an infinite 2-atom primitive cell of a
graphene-like sheet (or a 2-atom primitive FCC cell (like GaAs)).
Doesn't matter if it's not that physical. You also do not need fine
k-point