All third order anharmonic terms
Posted: 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.
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.