Dear All, I am working on the anharmonic force constant calculation following example 14. Since there is not much description of the output format (let me know if I am wrong), I have to guess what the parameters are.
Based on Debernardi's thesis and the discussions, I guess the code calculates C(0,q,-q), but this quantity is also a function of p, p', p'', which are the components of atomic displacements. I have read the code a little bit. The d3 matrix is stored in the quantity phi, which is a function of atom index and direction index( i guess?). However, I could not understand the output format as follows modo: 1 1 1 -0.138777878078E-15 0.000000000000E+00 -0.832667268469E-16 0.000000000000E+00 -0.277555756156E-16 0.000000000000E+00 -0.416333634234E-16 0.000000000000E+00 0.832667268469E-16 0.000000000000E+00 0.383064069101E+00 0.000000000000E+00 -0.111022302463E-15 0.000000000000E+00 0.383064069101E+00 0.000000000000E+00 -0.277555756156E-16 0.000000000000E+0 I cannot understand "modo" and (1,1). I suspect (1 1) means atom index, but there are p, p', p''. Which two (1,1) stands for? Also, in the README file. It shows something like C_{x,y,z} (0,0,0|1,1,1). I can understand (0,0,0) are the three q-points, but what does this 1,1,1 stands for? It does not look like phonon branch index or atom index. I have been struggling on this for quite some time. I really appreciate if anyone can help me to clarify this issue. Thanks, Hua -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120208/8af9892f/attachment.htm