Dear Siesta users,
> I have performed calculations for a silicon carbide (SiC) material.
> Analysis of Mulliken population revealed a charge transfer from C to
> Si of about 0.45|e| (well, I believe so). For instance:
> But, of course, I was expecting a charge transfer from Si to C. What
> may be wrong?
I have the same experience. I assume you used DZP basis. The
Mulliken-charge is very dependent on the applied basis set. I think that
the simple Mulliken-population analysis should not be used for basis sets
which involve diffuse orbitals. The reason could be in the definition of
the Mulliken charge which divides the overlap part equally between the
atoms in the bond. I think if it is possible to plot the charge density
around the atoms then you should see higher density around C-atoms and
lower density around Si-atoms as you expected.
Try to use smaller basis set and look at the trend.
Yours,
Adam Gali
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Dr. Gali Ádám Adam Gali, PhD
Budapesti Mûszaki és Department of Atomic Physics,
Gazdaságtudományi Egyetem, Budapest University of Technology and
Atomfizika Tanszék Economics
Budapest, Budafoki út 8., 1111 Budafoki út 8., H-1111, Budapest,
Hungary
telefon: 463-1580 telephone: [36]-(1)-463-1580
fax: 463-4357 fax: [36]-(1)-463-4357
e-mail: [EMAIL PROTECTED]
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