Dear Martina
1) How is the energy for the Initial and final structure estimated
when I keep the two configurations frozen?
By performing a single-point scf calculation. This is done in the
first neb.x step
2)Should it be exactly the same as the final relaxed energies that I
would get from completely separate calculations with the same
simulation conditions and same geometries?
3) If they are not expected to be exactly the same which factors
does the difference I may see depend on?
The energy should be the same, but keep also in mind that 1) neb.x
energies are printed in eV, pw.x energies in Ry; 2) conv_thr may be
different in the two calculations. It can be lowered down to two order
of magnitude below the input value near convergence of bfgs in "relax"
calculations, and it is strictly corresponding to the input value in
the first neb.x iteration; 3) You may be trapped in a different spin
state, you should check the PW.out file of the corresponding image to
be sure.
HTH
Giuseppe
"Stella, Martina" <[email protected]> ha scritto:
Hi,
I am new to NEBs calculations and I am getting familiar with the
method. I have a couple of questions, maybe trivial, but for which I
don't have an answer yet. Hopefully someone can help.
1) How is the energy for the Initial and final structure estimated
when I keep the two configurations frozen?
2)Should it be exactly the same as the final relaxed energies that I
would get from completely separate calculations with the same
simulation conditions and same geometries?
3) If they are not expected to be exactly the same which factors
does the difference I may see depend on?
Thanks.
M. Stella
Post-Doctoral researcher
Physics Department, King's College London
Strand,London WC2R 2LS UK
GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <[email protected]>
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