Hello
How to determine the total charge of a molecular system which contains transition metals in DFT calculations? for example, what would be the total charge of a pt-doped graphene system? should the system be considered neutral during the calculations or doping the Pt adds some charge to the system?
Thank you in advance
It can be neutral, cationic, anionic, be in different spin states. All depends on the situation. And this is not even about transition metals, its about any system.
Symplest examples:
[Fe(C5H5)2] can be neutral ferrocene, or [Fe(C5H5)2]+ cation, that together with counterion gives https://en.wikipedia.org/wiki/Ferrocenium_tetrafluoroborate
OH can be neutral radical, singlet anion or even cation.
Thanks for your answer Mr. Sharapa
Suppose we want to optimize the geometry of a divacancy Pt-Doped graphene sheet or any adatom-doped grapehene. Should we consider these system neutral or charged? what would be the total charge of these systems?
It can be neutral, cationic, anionic, be in different spin states. All depends on the situation. And this is not even about transition metals, its about any system.
Symplest examples:
[Fe(C5H5)2] can be neutral ferrocene, or [Fe(C5H5)2]+ cation, that together with counterion gives https://en.wikipedia.org/wiki/Ferrocenium_tetrafluoroborate
I would first consider system as neutral, but then look on the energies of homo and lumo - may be something else in the system works as counterion.
Thanks for your answer
would you please explain that how the total charge can be found through homo and lumo?
Thanks
if your HOMO-energy is positive or 0 - your system will lovely loose electrons to anything else in the near.
if your LUMO is minus few electronvolts - your system has so huge electronaffinity, that will steal electrons from nearby molecules, to become anion.
Example: What charge do BF4 have? You can assign it to be neutral radical, but then you can find significant electron affinity, that would turn this specy to closed-shell anion and nearby organic molecule - to cationradical.
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