[Pw_forum] VC_relax

[Vishal Gupta]

Dear Ari Paavo,
Thank you for your informative reply. Can you please tell me how to broaden
the occupation numbers ?
Sorry,  I am a little new at this.
Thank you.
Best Regards,
Vishal

On Thu, Mar 31, 2016 at 9:17 PM, Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>
wrote:

>
> Dear Vishal Gupta,
>
>   Your cut-off energy looks _very_ low, no matter which elements/pseudo
> potentials you do employ. Probably your system becomes metallic upon the
> relaxation, so I would include some kind of broadening of the occupation
> numbers, in addition possibly using the mixing mode 'local-TF', if you have
> vacuum in your system.
>
>     Greetings,
>
>        apsi
>
>
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
>   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
>     Ecole Normale Supérieure (ENS), Département de Chimie, Paris
>     Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935
>
>
> On Thu, 31 Mar 2016, Vishal Gupta wrote:
>
> Hi all,I've been running a vc_relax calculation on a 40 atom system. The
>> calculation works fine for some
>>
>> cycles. The total force had come down to 0.108. After some time. the
>> force started increasing and now the
>> iterations don't converge even in 400 steps. The input file is
>>  /
>>  &SYSTEM
>>                        ibrav = 0,
>>                          nat = 40,
>>                         ntyp = 1,
>>                      ecutwfc = 12 ,
>>  /
>>  &ELECTRONS
>>                  mixing_beta = 0.3 ,
>>              diagonalization = 'david' ,
>>              electron_maxstep = 200 ,
>>  /
>>
>> [&Ions/]
>> /
>> &CELL
>> cell_dynamics= 'sd' ,
>> cell_dofree='xy' ,
>> /
>>
>> CELL_PARAMETERS angstrom
>>     22.265358047804796    0.000000000000000    0.000000000000000
>>      0.000000000000000   11.131216979724510    0.000000000000000
>>      0.000000000000000    0.000000000000000   10.000000000000000
>>
>> P.S. Ive tried changing cell dynamics to 'damp-pr' , 'sd' and 'damp-w',
>> but the same problem persists.
>> Can anybody Please help me identifying the mistake ?
>> Thank You.
>> Best Regards,
>> Vishal Gupta
>>
>> B.Tech. 3rd year Mechanical
>>
>> Indian Institute of Technology Ropar
>> Rupnagar (140001), Punjab, India.
>> Email :- vishal.gupta at iitrpr.ac.in
>> RMML, IIT Ropar
>>
>>
>>
>> [487a748cedfb942f92401d52262f336d11784524388949.png]
>>
>>
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