QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: shyoun on December 30, 2022, 06:21

Title: van-der-Waals correction in LDA
Post by: shyoun on December 30, 2022, 06:21

Dear all,

There is no vdW correction in LDA in LCAOCalculator.
Unlike GGA, LDA sufficiently reflects vdW, so there is no correction? or is there correction for LDA?

Best regards.

Title: Re: van-der-Waals correction in LDA
Post by: Anders Blom on January 18, 2023, 00:31

There is no principal reason one cannot add vdW corrections to LDA, but the ones included in QuantumATK are based on PBE, mainly because they are the most successful and widely used (Grimme D2 and D3).

Your second statement is probably related to accidental cancellation of errors in LDA that give good results for interlayer distances with LDA, but for the wrong reasons (and probably just for some specific cases).

There is some background here: https://www.cp2k.org/_media/events:2015_cecam_tutorial:ling_vdw.pdf

Title: Re: van-der-Waals correction in LDA
Post by: shyoun on January 19, 2023, 06:48

Thank you for your answer!