All third order anharmonic terms

Phonons, DFPT, electron-phonon, electric-field response, mechanical response…

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shri
Posts: 1
Joined: Thu Sep 19, 2013 8:23 pm

All third order anharmonic terms

Post by shri » Thu Sep 19, 2013 8:43 pm

Hello,

The introduction to the response function tutorial on the ABINIT website says that "...some third derivatives of the total energy are also implemented". From the other tutorials and help files, I gathered that these derivatives refer to derivatives with respect to electric fields (I'm not sure if derivatives with respect to atomic displacements can be calculated in ABINIT, is that true?). I wanted to know whether it would be possible to compute all the third derivatives of total energy with respect to all ionic displacements for, say, a semiconductor. If so, can someone please point out a tutorial/resource where this is illustrated?

Thank you very much.

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