simulating vibrational spectra in the solid state, help me!

[Glaucio]

I am using cp2k for simulating vibrational spectra in the solid state, but 
I'm optimizing the crystal structures. My question is about the convergence 
criteria RMS gradient. Default is 3x10-4, but I'm used 1x10-6. The problem is 
the delay in the calculation, I want to avoid the presence of imaginary 
frequencies.
Someone could indicate their experiences?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20130511/5961cbc4/attachment.htm>