I am trying to run a DFT calculation for the adsorption of a potassium ion (K+) on a surface using Quantum Espresso . I am not sure how I can alter the electronic configuration of the the K-atom so that it becomes a K+ ion.
Kareem Mahmoud Gameel You should be able to set the tot_charge=1 for your case. But keep in mind that you would need to make adjustments to ensure that the calculation converges.
Hemanth Haridas Thank you. If I set the tot_charge = 1 , that would mean that that the whole system is positively charged and not necessarily that the potassium atom specifically is acting as a cation.
Kareem Mahmoud Gameel The general understanding from chemical intuition is that there would be some charge transfer going on, which would mean that the positive charge gets shared onto the entire system. So yes, it means that the unit cell is positively charged.
Kareem Mahmoud Gameel When you do a DFT calculation, the ground state electronic structure of the entire system is found (unless something goes wrong in the calculation), so if K wants to be K+ then it will give an electron to the surface. There's nothing you need to do or should do to tell QE about this (unless you want to charge the whole system, as mentioned above). You can check the charge state of each atom at the end to see if K is charged.
Matthew M. Montemore Thank you! I will try adding a total_charge=+1 to the whole system and see where this charge will go to.
To make myself more clear; I am trying to simulate the interactions between K+ ions and an electrode surface for electrochemical purposes. This shall mimic the anodic interactions of a K2SO4 electrolyte (K cations and SO4 anions) in a super capacitor. That's why I need to start with K+ ion as an input of electronic structure computations.
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nanostructures
- Thin Films