Re: [SIESTA-L] Fwd: [SIESTA-L] net charge calculation
I cannot agree that observing the relative change in Mulliken charges instead of absolute values would be correct. I had experience that DZP showed transfer of charge from surface to molecule, while TZP showed the opposite (though the charge transfer itself was very smal - about 0.1e) Was this an effect only in the Mulliken populations, or was it something from the calculation? Did you checked was was really happening with the charge transfer? I believe, yes. The binding energies (if BSSE corrections are taken) and the geometry were the same. I haven't checked too much, but I believe that if I were to draw DRHO it would be pretty the same (at least difference would not be noticeable by a naked eye). While the Mulliken charges themselves were very different. And their difference (i.e. charge transfer) was a little bit different.
Re: [SIESTA-L] Fwd: [SIESTA-L] net charge calculation
Oleksandr Voznyy wrote: There is an implementation for Bader analysis which can be used with SIESTA: http://theory.cm.utexas.edu/bader/ Some minor additional coding is needed for SIESTA, I did it and can share. Though, it's very rough, since I discontinued to work with it since Bader analysis gave me very similar results to Mulliken and Andrei's tool. I cannot agree that observing the relative change in Mulliken charges instead of absolute values would be correct. I had experience that DZP showed transfer of charge from surface to molecule, while TZP showed the opposite (though the charge transfer itself was very smal - about 0.1e) Was this an effect only in the Mulliken populations, or was it something from the calculation? Did you checked was was really happening with the charge transfer? M. -- Miguel Alonso Pruneda, Marie Curie Fellow 521 Birge Hall Department of Physics, UC-Berkeley, CA 94720 email: [EMAIL PROTECTED]
Re: [SIESTA-L] Fwd: [SIESTA-L] net charge calculation
There is an implementation for Bader analysis which can be used with SIESTA: http://theory.cm.utexas.edu/bader/ Some minor additional coding is needed for SIESTA, I did it and can share. Though, it's very rough, since I discontinued to work with it since Bader analysis gave me very similar results to Mulliken and Andrei's tool. I cannot agree that observing the relative change in Mulliken charges instead of absolute values would be correct. I had experience that DZP showed transfer of charge from surface to molecule, while TZP showed the opposite (though the charge transfer itself was very smal - about 0.1e)
Re: [SIESTA-L] Fwd: [SIESTA-L] net charge calculation
On Thu, 19 Apr 2007, Yurko Natanzon wrote: | Dear Adam Gali, Andrei Postnikov, | thank you for explanation. Actually, I'm not interested in particular | numbers, but want to observe changes in ionic charges of atoms, | neighboring to dopant and the dependence of such changes on a dopant | concentration (comparabale to undoped system). Dear Yurko: yes, this is (the only) reasonable approach - to look at trends throughout a row of otherwise similar systems. | Is it possible to do it with Mulliken analysis? Yes (as with any other method to evaluate these charges) | And how does the charge depend on the basis? If you ask about systematic observations - I don't know. My general impression is - the more complex the basis, the more weird the numbers. I can only add that, should you be interested in getting charges integrated over atomic spheres, I've written a simple tool for this, which you can download from http://www.home.uni-osnabrueck.de/apostnik/Software/grdint.f You run it as a standalone code, using the RHO calculated by Siesta. The basis shape then plays no role, and you can compare the numbers with results from other codes, which use integration over spheres. (Of course the numbers do depend on the sphere radii). Best regards, Andrei +-- Dr. Andrei Postnikov Tel. +33-387315873 - mobile +33-666784053 ---+ | Paul Verlaine University - Institute de Physique Electronique et Chimie, | | Laboratoire de Physique des Milieux Denses, 1 Bd Arago, F-57078 Metz, France | +-- [EMAIL PROTECTED] -- http://www.home.uni-osnabrueck.de/apostnik/ --+
