[Pw_forum] Reply (was Frequency and zero point energy calculations)

[Gabriele Sclauzero]

Dear Lihui,

    I have an update to this answer: for phonon calculations based on data produced by 
pw.x using gamma point tricks (i.e. K_POINTS GAMMA), you should use the code phcg.x in the 
Gamma/ directory, not ph.x.

regards,

GS

Gabriele Sclauzero wrote:
> Dear Lihui,
> 
> oulihui666 wrote:
>> Dear Gabriele Sclauzero,
>>   I am intend to calculate the frequency of CO2 molecule, so I should 
>> perform scf calculation at first, when setting k points as gamma, it 
>> will appear a error in the process of calculating frequency, as follows:
>> ***********************************************************************
>> from phq_readin. error #1
>> cannot start from pw.x data file using Gamma-point tricks
>> ***********************************************************************
> 
>  From what I can understand, this does not mean that you cannot do the calculation for the 
> Gamma point only, but rather that the calculation cannot be done using Gamma 
> point-specific algorithms (which are much faster than the general ones).
> You should anyway be allowed to do the calculation using
> K_POINTS AUTOMATIC
> 1 1 1  0 0 0
> which builds a k-point grid containing the Gamma point only, but does not use Gamma-point 
> tricks.
> 
> You can do the relaxations (and all other expensive pw calculations) using
> K_POINTS GAMMA
> and then, starting from the optimized atomic positions, do a nscf run using
> K_POINTS AUTOMATIC
> 1 1 1  0 0 0
> before the phonon run.
> 
> Cheers
> 
> GS
> 
> P.S: please avoid private mails and stick to the thread you started in the forum, so that 
> anyone can help and know when your problem has been solved. Thanks!
> 
> 
> 
>> So I do not set k point as gamma in scf calculation.
>>  
>>  Best regards
>>  Lihui 
>>
>> --
>> ======================================
>> Lihui Ou
>> PH.D Candidate in Electrochemistry                     
>> College of Chemistry and Molecular Science           
>> Wuhan University,/430072/,Hubei Province,China 
>> /E-mail:oulihui666 at 126.com <mailto:oulihui666 at 126.com>/
>> ======================================
>>
>>
>> ------------------------------------------------------------------------
>> 没有广告的终身免费邮箱,www.yeah.net <http://www.yeah.net/?from=footer>
> 

-- 


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