ABINIT Discussion Forums

Dear Abinit users,

Looking through Optic tutorial, in the input file toptic_1.in I found the variable tnons = 72*0.
I was trying to figure out the physical meaning of this parameter but still I'm a bit confused. So, could anyone explain the meaning of it in a simplified manner? Should it always be 72*0 in response calculations? Why 72?
Thank you!

Dear Maksim,
tnons gives the translation vector for each operation symmetry, i.e. they are all zero for symmorphic space groups. I would say to always let Abinit define it by default unless you want to trick something (I've never defined it in my input files so far...).
Best wishes,
Eric