Questions tagged [dispersion-correction]

Questions related to corrections due to dispersion effects in matter modeling.

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Set coordination number cutoff in CP2K's D3 dispersion

The D3 dispersion correction has 2 distance cutoff values. One for the calculation of coordination numbers, one for the energy contribution. In other implementations, such as vasp and DFTB+ (tblite), ...
Fuzzy's user avatar
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How to obtain imaginary frequency polarizability?

I am trying to find a way to calculate $C_6$ dispersion coefficients for some atoms and molecules. In papers and textbooks, this quantity is introduced using the Casimir-Polder integral from the ...
Szgoger's user avatar
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Does the relaxed density (and therefore the relaxed orbitals) depend on the final energy in OO-DHDF+D calculations?

During an OO-RI-ωB97X-2-D2 calculation on ORCA, the non-dispersion-corrected OO-DHDF part of the calculation is performed, the D2 dispersion correction energy added to the resulting OO-DHDF energy, ...
Kanghun Kim's user avatar
1 vote
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How I can consider Van der Waals interactions between two materials in Quantum ESPRESSO? [closed]

I'm working on a hybrid system (with two different materials). Could you tell me how I can take into consideration the Van der Waals interaction between them?
SOELHADFI's user avatar
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Choosing the right basis set for describing vdW-interactions with DFT-D3

I want to do some DFT calculations for structures of protonated alkaloid dimers. I know that a method of choice when vdW interactions are involved is the use of dispersion corrections. But now I am ...
C_Swann22's user avatar
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Electronic Convergence Issues with Nonlocal vdW-DF Functionals (in VASP)

Compared to say the DFT-D3 type of dispersion corrections (set with IVDW in VASP), I've found the nonlocal vdW-DF functionals (described here in the VASP Wiki) to be much more difficult to converge ...
CW Tan's user avatar
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DFT-D2 calculations in VASP and Gaussian

We are planning on comparing the results of Quantum dots and Bulk materials for our systems so we are planning to use Gaussian for QD and VASP for Bulk. Considering that we will be comparing their ...
Parmeet Singh EP 066's user avatar
7 votes
2 answers
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Are dispersion constant calculated differently for elements that are heavier than Xe?

How does one obtain the value of dispersion coefficient $C_6$ for elements that come after Xe. I am going through the original paper [1]. I can see that: $$\tag{1}C^a_6 = 0.05N(I^a \alpha^a),$$ where $...
Parmeet Singh EP 066's user avatar
6 votes
1 answer
246 views

For what DFT functional is useless to add D3 or similar corrections?

I would like to know for which DF is useless to add dispersion corrections. For example, I suppose that for the nonlocal density-based functionals such as wB97M-V it is unnecessary because the ...
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Cutoff length for vdW correction in DFT calculation [closed]

In classical MD simulations of lattice structures, whenever we are trying to incorporate vdW corrections to the atomic force calculation, we need to set up cutoff length beyond which the vdW ...
Lonitch's user avatar
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How might inclusion of a Grimme dispersion correction influence a simulation of a dense liquid that is not water?

I adapted an example first-principles water simulation to do simulations of liquid SiO2, but did not know what I was doing and did not remove a Grimme dispersion correction term. It would be great to ...
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Keesom and Debye forces in DFT

Do van der Waals corrected DFT functionals include Keesom and Deby corrections too or just London dispersion? Because when I look at these methods in detail, I see that there is just an attempt to ...
Chris's user avatar
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Should I add vdW interaction to estimate chemical potential of metallic elements?

I am considering layered oxides $\ce{LiCoO2}$. Previous papers suggested that vdW interaction should be added to get lattice parameters closer to experimental data. I would like to dope other elements ...
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Are dispersion correction methods for DFT (such as D3) useful for geometry optimization?

For what I know the DFT-D3 method or similar corrections that take into account dispersion effect, add this type of contribution through calculation of atom pairwise interactions at the end of an ...
NickZ's user avatar
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Calculation of dispersion energies for organometallic complexes with Gaussian

I've tried to calculate dispersion energies of some organometallic complexes with the Gaussian software using WB97XD/Gen (...
Yassamine's user avatar
4 votes
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179 views

What are the TS, MBD keywords for new (5.4.+) VASP versions? [closed]

I tried IVDW = 2202 for MBD as mentioned on the website but I got the following error: ...
Savir's user avatar
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SCAN-RVV10 geometry optimization

I'm using SCAN-RVV10 to optimize the hexagonal-BN but the optimized geometry doesn't look true as the calculated interlayer distance is far smaller than the experimental value(exp=3.35 Aangstrom, calc=...
Savir's user avatar
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5 votes
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Dispersion correction and band structure

Let's say I optimized geometry with PBE+D3. I want to carry out band structure calculation with HSE06, should I add the dispersion correction to the band structure calculation or not? I tried both and ...
Savir's user avatar
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10 votes
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How does MBD (MBD-NL) differ from DFT-TS?

Is anyone familiar with Tkatchenko's new MBD-NL method? How does it differ from DFT-TS? I couldn't understand everything from the paper.
Alfred's user avatar
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11 votes
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Band structure with additive dispersion methods

Let's say I optimized geometry with PBE+D3, does it matter if I make single point bandstructure calculation with just PBE or PBE+D3 since D3 is a additive method.
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Best vdW correction functional for transition metal dichalcogenides

For relaxation of transition metal dichalcogenides (e.g.: WS2) using the VASP code, what is the best choice for vdW correction method (e.g.: DFT-D2, DFT-D3 or optB88-vdW) that can give you good ...
Chi Kou's user avatar
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18 votes
1 answer
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Difference between Van der Waals (DFT-D and DFT-D3) corrections in ab-initio calculations

In Kohn-Sham DFT calculations, Van der Waals corrections are often implemented in the structure optimization calculations because the typical functionals such as LDA and GGA are found to not treat ...
livars98's user avatar
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24 votes
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What are the different ways of calculating dispersion constants?

There are many different dispersion corrections out there. The most famous is D3 [1] (and the new D4 [2]), but there's probably other approaches too. The dispersion energy can be written as: $$ E_{\...
schneiderfelipe's user avatar