[Pw_forum] Calculation of vibrational free energy through Quantum Espresso

[Lorenzo Paulatto]

> When I give the command ./fqha.x it asks file containing the dos. If you 
> can guide me in making the dos file too , I can try to calculate the 
> vibrational free energy with the dos file. Is the dos file being asked 
> by the fqha.x command is density of state of phonons in specific q's?
Dear Krishnendu,
you can produce a file with the phonon density of states (ph dos, or 
just dos) using the matdyn code. Check the example in 
PHonon/examples/example02 for an example matdyn input file (phdos.in).

One you have the ph dos file, that's fqha needs, just run it and follow 
the instructions, enter as many temperatures as you want and press 
CTRL-D when you are done. Or you can create an input file like this:
infile.phdos
outfile.free_h
  T_1
  T_2
  T_3
  ...
  T_n

Where T_i are the temperature you want in K, and feed it to fqha.x as
   fqha.x < input_file



hth


-- 
Lorenzo Paulatto - Paris