[CP2K:9441] Re: Hybrid functional calculation results show large difference with VASP

[Xiaoming Wang]

Hi,

Thanks for pointing out the time estimate for me. The largest ADMM basis I 
can afford is FIT11 for Cs, Ag, In and pFIT3 for Cl. Also with these larger 
basis, the band gap change is quite small, say 0.015 eV. With larger ADMM 
basis, the band gap tends to be slightly smaller, contrary to the case of 
Si. Is the behavior of nonsensitive dependence on the ADMM basis related to 
the high ionicity of the present structure?

Best,

Xiaoming

On Tuesday, September 19, 2017 at 11:05:39 AM UTC-4, jgh wrote:
>
> Hi 
>
> I would first try a larger ADMM basis, e.g. pFIT3. 
>
> The increase in CPU time for a full exchange calculation with 
> MOLOPT basis sets can be 100x - 1000x. 
>
> regards 
>
> Juerg 
> -------------------------------------------------------------- 
> Juerg Hutter                         Phone : ++41 44 635 4491 
> Institut für Chemie C                FAX   : ++41 44 635 6838 
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> -----cp... at googlegroups.com <javascript:> wrote: -----To: cp2k <
> cp... at googlegroups.com <javascript:>> 
> From: Xiaoming Wang 
> Sent by: cp... at googlegroups.com <javascript:> 
> Date: 09/19/2017 04:46PM 
> Subject: [CP2K:9441] Re: Hybrid functional calculation results show large 
> difference with VASP 
>
> Hi Marcella, 
> What do you mean by the 'smaller version'? If you are meaning a smaller 
> basis set for ABS, I did the test. To my surprise, the results don't change 
> much when I go to the smallest ABS, say cFIT3 for Cl, cFIT9 for Ag and In, 
> cFIT7 for Cs. Is this behavior reasonable? 
> Without ADMM, it seems that the computation would take extremely long time 
> with the same cpu cores. With ADMM, I can finish the calculation within 
> couple of minutes. However, without ADMM, it has taken me almost one hour 
> and the first OT step hasn't even appear in the output. Does this sounds 
> reasonable as well? 
> Best,Xiaoming 
>
> On Tuesday, September 19, 2017 at 4:58:43 AM UTC-4, Marcella Iannuzzi 
> wrote:Hi, 
> Can you test your system without ADMM? (maybe a smaller version of it)You 
> should compare the electronic properties obtained with and without ADMM to 
> verify whether the problems is there or somewhere else.RegardsMarcella 
>
> On Tuesday, September 19, 2017 at 8:23:59 AM UTC+2, Xiaoming Wang 
> wrote:Hi, 
> I checked the convergence of the primary basis size. To be specific, I 
> compared the DZVP and TZVP basis sets. The difference of the PBE band gap 
> is within 0.01 eV.  The PBE0 band gap without coulomb trunction also shows 
> small difference, say ~0.01 eV. The band gap variation by coulomb 
> truncation as in PBE0-TC-LRC scheme is larger, say 0.05 eV, but still not 
> too much.   
> Any other advice? 
> Best,Xiaoming 
>
>
>
>
>
>
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