[Pw_forum] phonon calculation problem

[Fen Hong]

Dear PWscf users and developers,
The frequency calculation is very time-consuming.
I read one paper, for example, isocynide molecule, they
only calculated partial vibrational spectra instead of full one.
Because the difference between  frequencies  from this two ways is marginal.
When isocynide adsorbed on Au(111) surface, the vibration of surface is not
considered because gold has quite large atomic mass compared with that of
first row atoms.

What I want to know is how to calculated particle frequency by fix the
position of the surface atoms.
I tried “nat_todo” in *.ph.in, but frequency  doesnot show is the out file.

Is there someone know how to do particle frequency
Thank you

Best Regards,
Takai
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20120223/d371afba/attachment.html>