[Pw_forum] Bulk modulus calculation

[vicky singh]

Thanks Dr. Sanjeev for the useful link


On Thu, Mar 6, 2014 at 10:28 AM, Sanjeev Gupta <physics.skgupta at gmail.com>wrote:

> Hi
>
> For bulk modulus, energy Vs lattice const., is always welcome.
> Otherway, there are lot of discussions on PWSCF forum, as one of by Prof.
> Eduardo Menendez.
>
>
>
> http://exciting.wdfiles.com/local--files/lithium-energy-vs-strain-calculations/elastic-paper.pdf
> and http://exciting-code.org/elastic
>
> download it take espresso i/o files.
>
> enjoy the day!
>
> bests
> sanjeev
>
>
> On Thu, Mar 6, 2014 at 9:32 AM, vicky singh <kirtinandan07 at gmail.com>wrote:
>
>> Dear QE users
>>    I am calculating the bulk modulus using the ev.x executable. The bulk
>> modulus obtained is extremely sensitive to the number of data i use in the
>> lattice parameter vs energy table. if i use three values a-x, a, a+x, where
>> a is the equilibrium lattice parameter and x is 0.01 or 0.02 bohr the value
>> of bulk modulus is very high as compared to i use 5 or 10 data. Bulk
>> modulus is the double derivative if energy w.r.t. equilibrium lattice
>> parameter.
>>    What should be the best method to obtain the bulk modulus of the
>> system. Also if you can provide any tutorial or help to calculate other
>> elastic constant it will be extremely helpful.
>>
>> Vicky Singh
>> RA, Bangalore
>>
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>>
>
>
>
> --
> With Best Regards,
>
> ------------------------------------
> Dr. Sanjeev Kumar Gupta
> Fulbright Post-Doctoral Scholar
> Dept. of Physics
> Michigan Technological University
> 1400 Townsend Drive, Houghton
> MI 49931, USA
> ------------------------------------
>
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