[Wien] hybrids + vdW

[tran at theochem.tuwien.ac.at]

Hi,

In WIEN2k the forces are implemented for LDA/GGA and LDA/GGA+D3, but not
for MGGA and hybrid. So, no relaxation of atomic positions
with MGGA and hybrid.

mBJ is not a functional derivative such that it is theoretically
impossible to define forces which have a physical meaning.

If the only way to relax atomic positions is with forces
(too complicated to do it "manually"), then you need to use
GGA or GGA+D3. Then, use hybrid or mBJ at the optimized
geometry for the electronic structure.

The stress tensor is not implemented in WIEN2k.

FT

On Tuesday 2017-05-16 16:28, Fabiana Da Pieve wrote:

>Date: Tue, 16 May 2017 16:28:35
>From: Fabiana Da Pieve <fabiana.dapieve at gmail.com>
>Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>Subject: [Wien] hybrids + vdW
>
>Dear Wien2k developers
>
>I have some simple questions before I start some new calculations:
>
>- is it possible to relax a structure with YS-PBE0 or HSE06, adding also simultaneously van der Waals corrections via the Grimme D3 method ?
>
>- if I understand well, one CANNOT relax a structure when considering mBJ.
>This sounds reasonable as I expect that forces and stresses are not calculated when considering the potential mBJ. Please correct me if I am wrong. I got a bit confused by a post this morning.
>
>- I guess it is anyway possible to run an SCF mBJ calculation (adding simultaneously the vdW via the D3 method) to further extract the band structure , on a structure that has been indeed PREVIOUSLY relaxed via combining YS-PBE0 (or HSE06) +D3. I guess
>the answer is yes, **please correct me in case I am wrong**.
>I have anyway some doubt about the adding of the D3 corrections. I am not really sure all this would make a sense, from the point of view of correctly considering vdW corrections in a consistent way.
>Is there a comment you might want to add ?
>
>Thank you very much in advance for your attention
>F.
>
>
>
>