[Pw_forum] problem in nmr calculation

Jones Tsz-Kai Wan jwan at phy.cuhk.edu.hk
Tue Nov 24 04:02:44 CET 2009


Typo -- I was using q_gipaw = 0.005 instead. -- Jones

On Tue, Nov 24, 2009 at 11:01 AM, Jones Tsz-Kai  Wan
<jwan at phy.cuhk.edu.hk> wrote:
> Dear Davide and Emine,
>
> The problem was fixed after I set q_gipaw to 0.05, but I have another
> error now, nmr calculation stopped and said:
>
>    from  grid_gather  : error #     46592
>     f_out too small
>
> I guess it's because I'm using to less k-points, I'm increasing the
> k-points to see if that happen again.
>
> Regards,
>
> Jones
>
> On Tue, Nov 24, 2009 at 10:26 AM, Jones Tsz-Kai  Wan
> <jwan at phy.cuhk.edu.hk> wrote:
>> Dear Davide and Emine,
>>
>> The problem was fixed after I set q_gipaw to 0.05, but I have another
>> error now, nmr calculation stopped and said:
>>
>>     from  grid_gather  : error #     46592
>>      f_out too small
>>
>> I guess it's because I'm using to less k-points, I'm increasing the
>> k-points to see if that happen again.
>>
>> Regards,
>>
>> Jones
>>
>> On Tue, Nov 24, 2009 at 1:42 AM, Emine Kucukbenli <kucukben at sissa.it> wrote:
>>> Dear John,
>>>>
>>>>     ATTENTION: ik=  10  ibnd= 20  eigenvalues differ too much!
>>>>        19.9838     19.4785
>>>> What is the reason of this and how can I avoid this?
>>>
>>> Not an expert on the issue yet, but cheking the code what I see is that:
>>> eigenvalues at k and k+q differ more than 0.2eV (from compute_u_kq
>>> subroutine) This violates the small q approximations I suppose. Have you
>>> tried with a smaller q?
>>> emine kucukbenli, phd student, sissa, italy
>>>
>>>
>>>
>>>
>>>
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