[Pw_forum] comparing gaussian03 with pwscf

[Eduardo Ariel Menendez Proupin]

If there is doubt on the approximations for lantanides, I suggest to make
some tests with something more "classic", such as NaCl or MgO and then
compare PWSCF vs GAUSSIAN with complete basis sets.

One question? What is the useful information provided by the knowledge of
the charge transfer? Can it be correlated to any measurable property
(reactivity, entropy, adsorcion enrgy, ....) or with any measurable and
difficult to calculate property?

Some years ago I calculated and reported some charge transfer and said
something about the ionicity. To know better, I calculated the charge
transfer in NaCl. For this, I integrated the charge density in the Voronoi
cells of Na and Cl, using the self consisten charge density and the
superposition of atomic densities. The difference is the charge transfer or,
more precisely, the charge that crosses the boundary of the Voronoi cells.
To my surprise, the charge transfer in NaCl is 0.1 electron, and not 1
electron as the textbooks suggest. I also tested it with MgO (0.2 instead of
2). So, where is hidden  the truth of the ionic bond?



-- 
Eduardo Menendez
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