Take a look at the following paper. They discus the effect of various methods in the determinations of water atomic charges:
http://onlinelibrary.wiley.com/doi/10.1002/jcc.20157/full F. Martin, H. Zipse, Charge distribution in the water molecule. A comparison of methods, J. Comput. Chem. 26 (2005) 97-105. DOI: 10.1002/jcc.20157 []'s, Camps On Mon, Oct 9, 2017 at 4:44 AM, Ulrich Biedermann <[email protected]> wrote: > Dear Dan, > I have noticed similar problems. Mulliken charges depend on the atomic > basis set used. In Siesta the cutoff radius (of H) seems to be the > critical parameter. I suggest that you check the dipol moment of an > isolated water molecule (10 Angstrom box). It should have the correct > magnitude and sign for the basis set settings you use. > > Regards, Ulrich. > > * From: * Dan Gil <[email protected]> > * To: * <[email protected]> > * Sent: * 06.10.2017 16:13 > * Subject: * [SIESTA-L] Mulliken Charges on Water > > Hi, > > I am using Siesta 3.2 and ran into a strange problem. > > I simulate a water molecule and the Mulliken charges are wrong. It shows > that the oxygen atom is positively charged and the two hydrogens are > negatively charged. The Hirshfeld and Voronoi populations are fine. Did I > run into a bug? > > *input.fdf* > NumberOfAtoms 3 > NumberOfSpecies 4 > > %block ChemicalSpeciesLabel > 1 13 Al > 2 14 Si > 3 8 O > 4 1 H > %endblock ChemicalSpeciesLabel > > PAO.BasisType nodes > > %block PAO.BasisSizes > Al DZP > Si DZP > O DZP > H DZP > %endblock PAO.BasisSizes > > XC.functional GGA > XC.authors PBE > > # SCF options > MaxSCFIterations 200 > DM.MixingWeight 0.25 # New DM amount for next SCF cycle > DM.Tolerance 1.d-6 # Tolerance in maximum difference > SolutionMethod diagon # OrderN or Diagon > MeshCutoff 400 Ry > DM.Require.Energy.Convergence .true. > DM.Energy.Tolerance 1.d-6 eV > > MD.TypeOfRun CG > MD.NumCGsteps 100 > MD.InitialTemperature 300.0 K > MD.TargetTemperature 300.0 K > > WriteHirshfeldPop .true. > WriteVoronoiPop .true. > WriteMullikenPop 1 > > LatticeConstant 1 Ang > > %block LatticeVectors > 9.5160000000 0.0000000000 0.0000000000 > -4.7580000000 8.2411000000 0.0000000000 > 0.0000000000 0.0000000000 48.2792733630 > %endblock LatticeVectors > > WarningMinimumAtiomicDistance 1.0 Ang > AtomicCoordinatesFormat NotScaledCartesianAng > %block AtomicCoordinatesAndAtomicSpecies < Coord.fdf > > *Coord.fdf* > 5.265981 -1.943725 -6.378528 3 > 4.222545 -1.943725 -6.378528 4 > 5.612381 -0.997652 -6.378528 4 > > *Output (excerpts)* > mulliken: Mulliken Atomic and Orbital Populations: > Species: O > Atom Qatom Qorb > 2s 2s 2py 2pz 2px 2py 2pz > 2px > 2Pdxy 2Pdyz 2Pdz2 2Pdxz 2Pdx2-y2 > 1 5.764 1.436 -0.027 1.363 1.793 1.235 -0.023 -0.003 -0.034 > 0.003 0.002 0.005 0.001 0.014 > > Species: H > Atom Qatom Qorb > 1s 1s 1Ppy 1Ppz 1Ppx > 2 1.118 0.845 0.036 0.063 0.104 0.070 > 3 1.118 0.845 0.036 0.091 0.104 0.042 > > Hirshfeld Net Atomic Populations: > Atom # Qatom Species > 1 -0.234 O > 2 0.117 H > 3 0.117 H > > Voronoi Net Atomic Populations: > Atom # Qatom Species > 1 -0.171 O > 2 0.086 H > 3 0.085 H > > Best Regards, > > Dan > > > > > ------------------------------ > ------------------------------------------------- > Max-Planck-Institut für Eisenforschung GmbH > Max-Planck-Straße > <https://maps.google.com/?q=Max-Planck-Stra%C3%9Fe%C2%A01&entry=gmail&source=g> > 1 > <https://maps.google.com/?q=Max-Planck-Stra%C3%9Fe%C2%A01&entry=gmail&source=g> > D-40237 Düsseldorf > > Handelsregister B 2533 > Amtsgericht Düsseldorf > > Geschäftsführung > Prof. Dr. Gerhard Dehm > Prof. Dr. Jörg Neugebauer > Prof. Dr. Dierk Raabe > Dr. Kai de Weldige > > Ust.-Id.-Nr.: DE 11 93 58 514 > Steuernummer: 105 5891 1000 > > > Please consider that invitations and e-mails of our institute are > only valid if they end with …@mpie.de. > If you are not sure of the validity please contact [email protected] > > Bitte beachten Sie, dass Einladungen zu Veranstaltungen und E-Mails > aus unserem Haus nur mit der Endung …@mpie.de gültig sind. > In Zweifelsfällen wenden Sie sich bitte an [email protected] > ------------------------------------------------- >
