[CP2K:9450] Re: Hybrid functional calculation results show large difference with VASP

[Matt W]

Hi,

I only see the check for InCl3, not the main system?

Matt

On Thursday, September 21, 2017 at 10:36:15 AM UTC+8, Xiaoming Wang wrote:
>
> Hi Matt,
>
> Actually I also did the calculation for a supercell of 21*21*21 with 320 
> atoms. PBE0 without TC are also tested, please see my benchmark tests in 
> previous post (attachment in reply to Ling).
>
> Best,
> Xiaoming
>
>
> On Wednesday, September 20, 2017 at 10:27:48 PM UTC-4, Matt W wrote:
>>
>> That ADMM basis is already pretty large, so whilst it might be the 
>> problem, first I'd check the cell size.
>>
>> Can you build a cell about 15 x 15 x 15 A or larger to allow you to 
>> extend the range of the hybrid out to 6 or 7 A?
>>
>> You are truncating at about 5.25 A, which might not be enough to be fully 
>> converged (note VASP won't be doing this as it works in K space). 
>>
>> Matt 
>>
>> On Thursday, September 21, 2017 at 8:36:29 AM UTC+8, Xiaoming Wang wrote:
>>>
>>> Hi Ling,
>>>
>>> Thanks for your comments. I have attached my benchmark results here. 
>>>  Based on my tests, it seems that the ADMM basis set size is not so 
>>> important for ionic crystals. One can get reasonable results even with 
>>> smallest basis sets. Btw, the cutoff and rel_cutoff used are well converged 
>>> values for my target property. So I think there is still room to improve 
>>> the ADMM basis for Ag and In (with semicore d states in the valence). To 
>>> check whether it is the problem of Ag and In ADMM basis, the simplest way 
>>> is to do the PBE0 calculations without ADMM. But the calculation takes me 
>>> too long time, as also pointed out by Juerg. I suspect if it is possible to 
>>> do HFX without ADMM using MOLOPT basis sets.
>>>
>>>
>>>
>>>
>>>
>>> Best,
>>> Xiaoming
>>>
>>> On Wednesday, September 20, 2017 at 6:20:09 AM UTC-4, S Ling wrote:
>>>>
>>>> Hi
>>>>
>>>> I am not sure whether you are using the same ADMM basis sets (see your 
>>>> initial input) for these new test calculations. One thing which I can see 
>>>> is that you are not using the largest available ADMM basis sets for some of 
>>>> the elements, e.g. the largest available ADMM basis sets for Cl, Ag and In 
>>>> are pFIT3, FIT12 and FIT13, respectively. Taking In as an example, the 
>>>> FIT13 ADMM basis set of In contains more p and d functions than FIT11, 
>>>> which may be important for your system. 
>>>>
>>>> You mentioned a few different functionals, including PBE, PBE0 and 
>>>> HSE06, and you have run quite a lot of benchmark tests. It would help if 
>>>> you can tabulate all the numbers you have got (including the reference), so 
>>>> we can understand your problem better.
>>>>
>>>> In addition, I can see you're using a CUTOFF of 250 Ry. Please also 
>>>> check whether your calculation is converged with respect to this parameter.
>>>>
>>>> Please also keep in mind that CP2K and VASP use different 
>>>> pseudopotentials and basis sets. I wouldn't expect the two codes to give 
>>>> the same numbers for your target properties. If you look into literatures, 
>>>> you will also find people reporting different numbers for the same property 
>>>> using the same method and code.
>>>>
>>>> SL
>>>>  
>>>>
>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20170920/6c40c1e3/attachment.htm>