I have an Iron complex in which Fe has oxidation state 3. I want to mention the oxidation state explicitly. Is there any way in vasp to mention the oxidation state of constituent atoms.
No, you cannot initialize atomic charges in VASP or other plane-wave DFT codes. But you can initialize the magnetic moments using the MAGMOM tag (see http://cms.mpi.univie.ac.at/vasp/vasp/MAGMOM_tag.html). For high-spin Fe3+, for example, MAGMOM=5.
Thanks Ricardo for your valuable answer. I have one more query about mention magnetic moment using MAGMOM tag. Well, I am doing geometry optimization of Fe2OCl6. In this molecule the two Fe ions have different magnetic moment, one is having 3 and other 2. So my question is how I will set the magmom in this case.
Thanks in anticipation
Dear Showkat,
the MAGMOM tag requires a number for each atom in POSCAR. For example, if your POSCAR has 2 Fe3+ (in high-spin state), 1 O2- and 6 Cl-,, your line would be:
MAGMOM = 5 5 0 0 0 0 0 0 0
or in a shorter format:
MAGMOM = 2*5 1*0 6*0
Now if one of the two Fe (say the first one) is Fe2+ high-spin, then
MAGMOM = 4 5 1*0 6*0
I am assuming here that what you said about one having 3 and the other 2, you were talking about the oxidation states, not about the magnetic moments. Btw I am also assuming that you know what you are doing with that molecule, because typically Fe2OCl6 is a molecular anion with overall charge -2, where both Fe in 3+ oxidation state...
Good luck!
Ricardo.
Thank you very much. Your answer has helped me a lot. Also you are right that Fe2OCl6 is a charged molecule with charge -2. This I have taken care using NELECT tag in VASP. The only problem was how to set the magmom tag.
Once again Thanks for for kind support.
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