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.
All third order anharmonic terms
Moderators: mverstra, joaocarloscabreu