[Pw_forum] calculating equilibrium lattice constant

[Nicola Marzari]

mohnish pandey wrote:
> I am beginner of quantum espresso. I am trying to calculate the 
> lattice constant for zinc oxide graphitic and wurtzitic structure . I 
> am using a script for that. But I have to see each and every file to 
> check the energy and to decide which one is minimum. Can you guys 
> please help me to get a shortcut for this I mean after running a loop 
> I get a minimum energy file instead of doing it manually and then 
> deciding which lattice parammeters fits to minimum energy..
>
> Thanks in advance.
> Mohnish Pandey

Dear Mohnish,

Use the linux command 'grep' to extract from a file keywords like 'total 
energy';
in particular the converged one has an exclamation mark '!'. so,

grep '!' ZnO_out*

would work, where ZnO_out* includes all the files whose name starts with 
ZnO_out.

Familiarize yourself with the 'awk' command, with the program 'xmgrace',
and have a close look at all examples in media.quantum-espresso.org and
ocw.mit.edu/OcwWeb/Materials-Science-and-Engineering/3-320Spring-2005/CourseHome/
(before posting again).

Best luck !

          nicola


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Prof Nicola Marzari   Department of Materials Science and Engineering
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