Dear Yurko Natanzon,
take care! Mulliken-charges could be meaningless by using diffusing
orbitals. Draw the net charge density around the atoms (you can do it by
SIESTA and utility programs provided with) and you can see that O is
negatively polarized while Si is positively polarized opposite what
Mulliken-charges would indicate. I suggest to implement and use
Bader-charges for analyses which DOES NOT depend on the basis set.
Yours,
Adam Gali
> Species: Si
> Atom Qatom Qorb
> 3s 3s 3py 3pz 3px 3py 3pz 3px
> 3Pdxy 3Pdyz 3Pdz2 3Pdxz 3Pdx2-y2
> 1 4.026 0.404 0.474 0.308 0.152 0.308 0.254 0.394 0.254
> 0.338 0.330 0.259 0.330 0.219
> 4 4.026 0.404 0.474 0.308 0.152 0.308 0.254 0.394 0.254
> 0.338 0.330 0.259 0.330 0.219
>
> Species: O
> Atom Qatom Qorb
> 2s 2s 2py 2pz 2px 2py 2pz 2px
> 2Pdxy 2Pdyz 2Pdz2 2Pdxz 2Pdx2-y2
> 2 5.987 1.136 0.383 1.391 1.164 1.391 0.139 0.226 0.139
> 0.003 0.005 0.003 0.005 0.003
> 3 5.987 1.136 0.383 1.391 1.164 1.391 0.139 0.226 0.139
> 0.003 0.005 0.003 0.005 0.003
> 5 5.987 1.136 0.383 1.391 1.164 1.391 0.139 0.226 0.139
> 0.003 0.005 0.003 0.005 0.003
> 6 5.987 1.136 0.383 1.391 1.164 1.391 0.139 0.226 0.139
> 0.003 0.005 0.003 0.005 0.003
>
> mulliken: Qtot = 32.000
>
> then oxygen has positive ionic charge (6-5.987), and silicon has
> negative (4-4.026). Does it make any sense??
>
> On 19/04/07, Vasilii Artyukhov <[EMAIL PROTECTED]> wrote:
> > Just subtract the ionic charge from the Mulliken population, you will get
> > -.514 for O and +1.028 for Ti.
> >
> > 2007/4/19, Yurko Natanzon <[EMAIL PROTECTED] >:
> > > Dear SIESTers,
> > > I wonder how to calculate net ionic charge with SIESTA. For example, I
> > > have TiO2 anatase supercell with 12 atoms. Pseudopotential for Ti has
> > > valence electrons in 3s2 3p6 3d2 4s2 (12 electrons), O has 2s2 2p4 (6
> > > electrons). Then i set WriteMullikenPop 2 and obtain
> > > 10.972 for each Ti
> > > 6.514 fo O
> > > Total charge is 10.972*4+6.514*8 = 96 which equals the total number of
> > > valence electrons. Then how to obtain net electric charges of Ti and O
> > > atoms? If it is the difference between number of valence electrons and
> > > a charge obtained by SIESTA, than it is much lower, than is reported
> > > in other calculations. Net charge should be around +2 for Ti and -1
> > > for O.
> > >
> > > --
> > > Yurko Natanzon
> > > PhD Student
> > > Henryk Niewodniczański Institute of Nuclear Physics
> > > Polish Academy of Sciences
> > > ul. Radzikowskiego 152,
> > > 31-342 Kraków, Poland
> > > Email: [EMAIL PROTECTED], [EMAIL PROTECTED]
> > >
> >
> >
>
>
> --
> Yurko Natanzon
> PhD Student
> Henryk Niewodniczański Institute of Nuclear Physics
> Polish Academy of Sciences
> ul. Radzikowskiego 152,
> 31-342 Kraków, Poland
> Email: [EMAIL PROTECTED], [EMAIL PROTECTED]
>
>
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Dr. Gali Ádám Adam Gali, PhD
Budapesti Műszaki 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]
http://www.fat.bme.hu/homepages/galia/index.en.html
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