Oleksander,
I know. As I said, I am just trying to find out, maybe in a desperate way, how
to correctly calculate the solvation enthalpy of carbon in alpha-iron with
Siesta in order to be able to reproduce results in the literature, which have
been obtained with plane-waves. What I sent you was just one of those
different attempts, far the worst one, indeed (-8.04 eV). The best I obtained
up to now was not considering any BSSE correction (PW: 0.58 eV; me, with
Siesta: 0.30 eV). The geometries, on the other hand, are in nice agreement
between PW and LCAO. So I guess the remaining discrepancy in the energy
differences is due to BSSE. What I do not know is where to put the ghost atoms
and if I have to add other terms in the equation (and, if so, which ones).
Roberto
________________________________
From: Oleksandr Voznyy <o.voz...@usherbrooke.ca>
To: SIESTA-L@listserv.uam.es
Sent: Thursday, January 8, 2009 4:37:30 PM
Subject: Re: [SIESTA-L] Still energy differences and BSSE corrections
> Well, I am just trying to figure out what to do, maybe in wrong ways most of
> time. Up to now, the best result I obtained for C interstitial in iron was
> without any BSSE correction.
Roberto, please, read my previous email again. It looks like the problem in
your case is not in BSSE - you are just calculating a different property but
comparing it to enthalpy (which has a different definition):
enthalpy
H = E(Fe_n+C_1) - n*E(Fe_in_iron) - E(C_in_graphite)
E_cohesive = E(Fe_n+C_1) - n*E(Fe_lone_atom) - E(C_lone_atom)
You are calculating even something else different.
Just make sure you are using the same formula to which you compare.
