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how to get mechanical constant
Posted: Fri Oct 15, 2010 4:59 am
by dyc_2008
dear all：
after relaxation。I get the optimistic supercell。so how to get any mechanical constant at a given direction。such as strain tensor。
<span class='smallblacktext'>[ Edited ]</span>
how to get mechanical constant
Posted: Tue Oct 19, 2010 9:43 am
by riche
Dear dyc_2008,
Could you please make your question specific?
What do you mean by mechanical constants? What do you need strain tensor for?
how to get mechanical constant
Posted: Tue Oct 19, 2010 2:12 pm
by dyc_2008
may be i have used wrong words ‘strain tensor ’。
i just want to compare the elastic behavior of two materials。
how to get mechanical constant
Posted: Tue Oct 19, 2010 4:15 pm
by riche
Then just calculate the elastic constants.
how to get mechanical constant
Posted: Tue Oct 19, 2010 5:43 pm
by forsdan
@dyc_2008: If you have access to vasp 5.2, then you can use IBRION=6 and ISIF>= 3 to calculate elastic constants. Please see the manual
http://cms.mpi.univie.ac.at/vasp/vasp/I ... ION_6.html
Otherwise you will have to resort to the standard strain-stress or energy-strain relationships for your structure, and evaluate them by yourself by using several supercell calculations.
Cheers,
/Dan