QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: AsifShah on April 10, 2023, 14:07

Title: DFT calcualtions using LCAO
Post by: AsifShah on April 10, 2023, 14:07

Dear admin,

Are DFT calculations using ATK LCAO calculator reliable for interfaces between 2D materials such as WS2 and Gold?
I have seen some discrepancies between interfacial distances calculated from VASP using plane-wave and ATK using LCAO.

Title: Re: DFT calcualtions using LCAO
Post by: dprai on April 11, 2023, 08:42

Did you take BSSE incorporating dispersion correction into consideration during the optimisation process?

Title: Re: DFT calcualtions using LCAO
Post by: AsifShah on April 11, 2023, 17:40

That is not possible as it gets very expensive computationally to optimize with BSSE. That is suitable for molecules on surface not interfaces with large number of atoms, I guess.

Title: Re: DFT calcualtions using LCAO
Post by: Anders Blom on April 25, 2023, 22:32

Which dispersion correction are you using? This is probably more relevant than BSSE in this case, which is more applicable when computing the formation energy.

Title: Re: DFT calcualtions using LCAO
Post by: AsifShah on May 1, 2023, 20:04

DFTD3

Title: Re: DFT calcualtions using LCAO
Post by: Anders Blom on May 2, 2023, 07:17

Ok. Some small difference in results can always occur between different basis sets and pseudopotentials. It should make the final conclusions of the calculations wrong or invalid, as long they are internally consistent. You could test by running with the QuantumATK planewave basis set, to at least have the same pseudopotential for LCAO and PW.