[CP2K:7065] Re: DFT-D3 parameters for PBEsol

[Tobias Kraemer]

Dear SL,


thanks for the clarification, this confirms what I thought. I am fairly 
familiar with the D3 method as far as more conventional quantum chemistry 
packages are concerned, so I wanted to make sure that I am also doing the 
right thing in CP2K.  
Your comment on the basis set dependence is interesting, something that I 
must admit I wasn't aware of. I will look into this. Thanks for pointing 
this out, very helpful.

Tobi

 


On Saturday, October 17, 2015 at 6:14:53 PM UTC+1, S Ling wrote:
>
> Yes, the dftd3.dat file is the same, and you can set the D3_SCALING 
> parameters manually in the input. Please use the correct scaling parameters 
> either corresponding to zero damping or to BJ-damping. Please note these 
> parameters listed on the D3 webpage are for calculations using very large 
> basis sets in which case the contribution from basis set superposition 
> errors (BSSEs) can be neglected. If you look at the Supporting Information 
> of the original paper on the D3 method, the authors have provided 
> additional scaling parameters for calculations using moderate basis sets 
> which are more likely to be affected by BSSE. You may try both set of 
> scaling parameters and see which gives better agreement in comparison with 
> experiment for your particular system.
>
> SL
>
>
> On 16 October 2015 at 12:46, Tobias Kraemer <161br... at gmail.com 
> <javascript:>> wrote:
>
>> Hello Juerg. 
>>
>>
>> as far as the dftd3.dat file is concerned, this one is left unchanged I 
>> assume? The parameters can then easily be set with the D3_SCALING keyword.
>>
>> Also thanks for the clarification with regards to the choice of 
>> basis/potential. This certainly is helpful to know.
>>
>>
>> Tobias
>>
>>
>> Tobi
>>
>>
>>
>>
>> On Friday, October 16, 2015 at 10:31:39 AM UTC+1, Tobias Kraemer wrote:
>>>
>>> Hi all,
>>>
>>>
>>>
>>> I am doing a few test calculations with the PBEsol functional, and it 
>>> appears that D3 parameters are not implemented for this functional (I am 
>>> using version 2.7).
>>> I guess it might be an option to use the parameters from PBE, but I am 
>>> not convinced this is a good idea. On a similar note, I am wondering about 
>>> the specification
>>> of the potentials in this case as well, since I don't find any for 
>>> PBEsol. I have used the specific potentials for PBE, assuming that this 
>>> might be a valid approximation.
>>> The presence of Rhodium in my system seems to limit the choice of 
>>> functional to PBE (which I am currently using), PADE and BLYP. So, more 
>>> generally I am asking 
>>> the question if there is a way to increase the selection. How dangerous 
>>> is it to mix potentials and functionals. Perhaps using PBE with PBEsol is 
>>> an option, the combination of BLYP with B3LYP has been suggested somewhere 
>>> on this forum if I am not mistaken. 
>>>
>>> This is something I have been wondering about for a while, since I would 
>>> like to explore a few more functionals, but I seem to be somewhat limited 
>>> in my choice. Closely interlinked is the question for the D3 
>>> parametrization. 
>>>
>>> You suggestions are highly welcomed. 
>>>
>>>
>>> Thanks 
>>>
>>>
>>> Tobias  
>>>
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