Hi, I am using Gaussian 09w for my DFT studies. Currently, i am doing DFT calculation using LANL2DZ basis set for my copper(II) and zinc(II) complexes while, 6-31G+dp basis set for my ligand. The complexes turned out to have doublet spin while ligand is having singlet spin. May i know how does this spin affects our calculation? is it valid? how do i calculate the reactivity descriptors using this alpha and beta spin?
As soon as the ground state gets degenerate, DFT may run into problems since the fundamental Hohenberg-Kohn theorems are only proven for a non-degenerate ground state to my extent of knowledge.. You can be lucky and get a result close to reality, but I am not aware of systematic statements like expansion or compression of the geometry.
Edit: there are of course dependencies whether you imposed full or partial restrictions on your calculation, i.e. whether your spin orbitals are completely independent or whether you force them to be the the same to some extent or completely. Unrestricted calculations give the correct dissociation behaviour, but restricted caluclations may or may not be closer for the equilibrium state:
https://chemistry.stackexchange.com/questions/9743/is-there-an-energy-cost-associated-with-flipping-the-spin-of-an-electron
I would suggest one influences direct exchange correlation and the other does not. Can't beat Kxc.
- Badges
- Science topic
- Similar topics
- Biological Science
- Biochemistry
- Enzymology
- Enzymes