[Pw_forum] Convergence problem for relax calculation

[Mitul Mundra]

I changed the value of ecutwfc = 80 and ecutrho = 880 but the calculation
is still not converging. In my calculations, I didn't add degauss in my
input file, so it was using the default value of 0. Can you please suggest
how much should I keep my degauss value at? Also, should I change smearing?

Thanks
Mitul Mundra
Final year Dual Degree Student
Department of Chemical Engineering
IIT Kanpur


On Tue, Mar 4, 2014 at 11:54 PM, Bramha Pandey <pandey.bramha at gmail.com>wrote:

> Dear Mitul and Chugh,
> (1) points will not affect any more and ignored by code itself.
>
> (2) points is a valid point because you are using
> ecutwfc = 40,
>  ecutrho = 320,
> But by seeing the Si and Li USPP pseudo, it is suggested that
> ecutwfc is 38 and 78 for Si and Li respectively so used max one about 80
> and check convergence at that value.
> ecutrho=11 to 12 times of ecutwfc for ultrasoft pseudo.
> so it may be set 80*11=880
>
> By setting these parameters see the calculation if it is converged, if not
> try from degauss as suggested earlier.
>
>
>
> On Wed, Mar 5, 2014 at 1:10 PM, <manchugh at iitk.ac.in> wrote:
>
>> Mitul
>>
>> 1. &CELL namelist is used only if Calculation is 'VC-RELAX' or 'VC-MD'.
>> 2. Are you taking converged values of ecutwfc and ecutrho (if not, first
>> optimize these two)?
>>
>> Hope this helps!
>>
>> Manjusha
>> Department of Chemistry
>> IIT Kanpur
>>
>>
>> > Dear QE users,
>> >
>> > I am a beginner in electronic structure calculations and I have been
>> > trying
>> > to do relax calculations for my system. The input and output files are
>> > attached along with this mail. My calculations are not converging and I
>> > have tried a number of changes discussed on our forum earlier. I have
>> > changed the value of mixing_beta from 0.7 to 0.3, I have also increased
>> > ecutrho from 160 to 240 to 320 as I am using ultrasoft pseudopotentials.
>> > But all my efforts have been futile till now. I would be extremely
>> > thankful
>> > if anyone could suggest me something which can help my calculations
>> > converge.
>> >
>> > Thanks
>> > Mitul Mundra
>> > Final year Dual Degree Student
>> > Department of Chemical Engineering
>> > IIT Kanpur
>> > _______________________________________________
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>>
>>
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>
>
>
> --
> Thanks and Regards
> Bramha Prasad Pandey
> GLA University
> Mathura (U.P)
> INDIA.
>
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