[Wien] how to use optB88-vdW with wien2k-18.1 (fwd)

[Dr. K. C. Bhamu]

Hii Tran,

Sorry to interrupt you again,

I see in UG that I need to modify case.in0 with EX_OPTB88 *EC_LDA *VX_OPTB88
*VC_LDA*

I am dealing all other cases with PBE so should I change LDA to PBE or
optB88_vdw is run only with LDA so that I should not change anything as in
above EX/EC/VX/VC?
Page number 116-118 of UG does not say much clear about PBE.



regards
K.C. Bhamu

On Fri, Aug 17, 2018 at 12:49 AM, <tran at theochem.tuwien.ac.at> wrote:

> Hi,
>
> The file case.r2v_nlvdw will be generated and used during the
> calculation. You don't need to care about it.
>
> The steps for DOS, band structure and optics are exactly the same
> as with usual LDA or GGA.
>
> The extra computational time due to NLVDW does not depend on
> RKMAX or k-mesh. It depends on the size of the unit cell and on
> the value of plane-wave expansion cutoff GMAX in case.innlvdw.
>
> If you don't need to optimize position of atoms in the
> unit cell (i.e., no "-min"), then replace "T" by "F" in the
> last line of case.innlvdw. This will reduce significantly
> the NLVDW computational time.
>
> F. Tran
>
> Dear Wien2k users
>>
>> I have a few questions for optB88-vdW with Wien2k_18.1.
>>
>>
>> I need to use optB88-vdW for a perovskite structure.
>>
>> What I found from the mailing list and UG;
>>
>> 1. Need two files case.in0 and case.innlvdw to use this function and can
>> optimize the structure with this NL functional.
>> 2. One should add "–nlvdw" run(sp)_lapw script.
>>
>>
>> Now I have below queries:
>>
>> 1. It is mentioned to use "case.r2v_nlvdw" file [1], but in UG nothing is
>> said about this file. If we need to use
>> case.r2v_nlvdw then how to recall it?
>>
>> 2. Do we need to treat the step in the same way as we do for doss,
>> optical and band structure or we need to modify them? If
>> we need to modify these steps then what are the necessary changes (x -h
>> xxxx show nothing about -nlvdw for calculating these
>> properties)?
>>
>> 3. How expensive is in comparison to PBE? If I use 12x12x12 mesh for PBE
>> then how much I can reduce the mesh size (running on
>> 16 processor CPU)?
>>
>>
>> [1] https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at
>> /msg16549.html
>>
>>
>>
>> Thanks and regards
>>
>> K.C. Bhamu
>
>
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