Hi The problem of integration or population analysis is a common problem in PW codes and for solids in general. Since the "idea" of atomic-like orbital doesn't have sense anymore, and a band-like concepts is the important one. The integration around and mt-sphere is just for having a rough idea about local magnetic moments, and the "observable" magnitude is just the Qup-Qdn in cell. However I remember a paper from P.Novak where he studied the local magnetic moment (using Wien2k) first in the muffin-tin (MT) sphere, and then He extrapolate this value according with percentage of radial 3d-isolated-atomic-orbital. MagneticMoment=MM(muffin-tin-sphere)*area(3d-isolated-atomic-orbital between r=0 - infinity)/area(3d-isolated-atomic-orbital between r=0 - MT radius) Regards Ricardo ------------------------------------------------------------------------- ----- Ing. Quím. Ricardo Faccio Mail: Cryssmat-Lab., Cátedra de Física, DETEMA Facultad de Química, Universidad de la República Av. Gral. Flores 2124, C.C. 1157 C.P. 11800, Montevideo, Uruguay. E-mail: [EMAIL PROTECTED] Phone: 598 2 9241860 Int. 109 598 2 9290705 Fax: 598 2 9241906 Web: http://cryssmat.fq.edu.uy/ricardo/ricardo.htm ----- Original Message ----- From: Vasilii Artyukhov To: SIESTA-L@listserv.uam.es Sent: Tuesday, April 24, 2007 8:01 AM Subject: Re: [SIESTA-L] A question about local magnetic moment
Hi Marcos, Yes, the arbitrariness of radius choice is exactly what I'm talking about. There's a strict way to choose the integration region using the geometrical properties of the density. I'm not very aware about the details or what codes can do it. If someone's interested in having a postprocessing tool for such an analysis, I could look it up in more detail. 2007/4/24, Marcos Verissimo Alves <[EMAIL PROTECTED]>: Hi Vasilii, I guess so. I remember one of the e-mails of the list, in which Emilio talks about the calculation of PDOS in siesta. Since it is mulliken-like in nature, it would depend on the basis set as well. However, the integration over atomic spheres is what makes me a bit worried on practical aspects: how to choose the sphere radius? Although it would have the advantage of being effectively independent of the basis set, as you say, I don't see, in principle, a reasonable way of choosing the radii. Maybe there is, but I really can't think, at the moment, of any reasonable way. Any tips? Marcos > Dear Marcos, > > It seems like a very nice idea, but doesn't PDOS depend strongly on the > basis set, as well? I still think that the most reliable choice would be > to > work directly with the total spin density. > > 2007/4/23, Marcos Verissimo Alves <[EMAIL PROTECTED]>: >> >> This question has just come to discussion on the list in the last few >> days... Using the mulliken populations would be one way of doing it. >> Another would be to use Andrei Postnikov's tools for integration of >> charge >> density over atomic spheres. Yet another way would be to calculate the >> PDOS for each atom with a small smearing, then integrate over the >> energies >> up to the Fermi level. Seems complicated but with some shell scripting, >> sed and a small fortran/c program to integrate the PDOS it can be >> accomplished without too much difficulty. >> >> Cheers, >> >> Marcos >> >> >> > Is it right if only use the value of "SPIN-UP - SPIN-DOWN" in Mulliken >> > population analysis? >> > >> >> Dear Siesta usrers, >> >> >> >> How to get the local magnetic moment of each atom in the clusters, >> >> molecules, or solids using siesta code? >> >> >> >> Best regards, >> >> C. H. Hu >> >> >> >> >> > >> > >> >> >> -- >> Dr. Marcos Verissimo Alves >> Post-Doctoral Fellow >> Condensed Matter and Statistical Physics Sector >> International Centre for Theoretical Physics >> Trieste, Italy >> >> -------- >> >> I have become so addicted to vi that I try to exit OpenOffice by typing >> :wq! >> > -- Dr. Marcos Verissimo Alves Post-Doctoral Fellow Condensed Matter and Statistical Physics Sector International Centre for Theoretical Physics Trieste, Italy -------- I have become so addicted to vi that I try to exit OpenOffice by typing :wq!