Hi,
I see few papers which use D2 correction with LDA and HSE06 that use VASP.
I was wondering if D2 correction can be used with above two functional.
Please comment on the above statement.
Thanks
D2 Correction
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kelum
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Re: D2 Correction
There should be no issue with using the D2 (or any other dispersion correction) with the HSE functional in VASP.
Compared to a PBE-D2 calculation, you only need to add the D2 parameters into INCAR (called, I believe, VDW_S6 and VDW_SR),
as by default, the parameters for the PBE functional would be used and this is not the best option.
(For weakly bonded molecular dimers in the gas phase, HSE gives quite a stronger binding than PBE so that the
results would not be optimal.) Unfortunately, I think there are no official HSE parameters for D2 or D3. But as HSE and PBE0
give almost identical results for the gas phase dimers (<1meV differences in binding energies in S22 test set), you can use the PBE0 parameters
for HSE as well, which can be taken here for the -D3 scheme:
http://www.thch.uni-bonn.de/tc/index.ph ... ng=english
For -D2 and PBE0, a quick search doesn't show any reasonable parameters, but maybe someone somewhere has them.
In any case you might consider using -D3 instead.
For LDA dispersion corrections make little sense as it ovebinds hydrogen bonded dimers and reasonably binds dispersion bonded dimers in the gas phase.
Similarly, you get too much binding for solids. Adding additional binding from dispersion would only make things worse (in most of the situations).
Compared to a PBE-D2 calculation, you only need to add the D2 parameters into INCAR (called, I believe, VDW_S6 and VDW_SR),
as by default, the parameters for the PBE functional would be used and this is not the best option.
(For weakly bonded molecular dimers in the gas phase, HSE gives quite a stronger binding than PBE so that the
results would not be optimal.) Unfortunately, I think there are no official HSE parameters for D2 or D3. But as HSE and PBE0
give almost identical results for the gas phase dimers (<1meV differences in binding energies in S22 test set), you can use the PBE0 parameters
for HSE as well, which can be taken here for the -D3 scheme:
http://www.thch.uni-bonn.de/tc/index.ph ... ng=english
For -D2 and PBE0, a quick search doesn't show any reasonable parameters, but maybe someone somewhere has them.
In any case you might consider using -D3 instead.
For LDA dispersion corrections make little sense as it ovebinds hydrogen bonded dimers and reasonably binds dispersion bonded dimers in the gas phase.
Similarly, you get too much binding for solids. Adding additional binding from dispersion would only make things worse (in most of the situations).