I am interested in outputting phonon frequencies. I have outputted them with no problem before by using
“output freq text frequencies.txt” on some systems before. However, it’s now giving me lots of *******, possibly due to large frequency values. Is there a way to output very large frequency values?
In addition, is there a way to output dynamical matrix only (similar to outputting frequencies)?
The frequency output for GULP is designed to handle the range of physical vibrational frequencies that materials can have. So the first thing to point out is that if you have **** etc then it means something has gone wrong in your calculation such that you are getting unphysical vibrations (e.g. the structure has collapsed). If you really want to know what these ugly unphysical modes are then you’ll probably need to edit the format statements in the code to allow for larger numbers and then recompile. If you want the dynamical matrix then you can use the keyword (see dynamical_matrix in the help text) to output this. If you add “verbose” and “debug” you’ll get more of the working along the way.