van-der-Waals correction in LDA

[shyoun]

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.

[Anders Blom]

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

[shyoun]

Thank you for your answer!