[Pw_forum] negatives frequencies phonon calculation

[Halima Zaari]

Dear Espresso users
I have performed a phonon calculation of an oxides on 2x2x2 q grid.
 I am using pw.x , ph.x; q2r.x, matdyn.x and lambda.x  to calculate the
 phonon-electron coupling
. However I am getting" NAN" in the file lambda.dat and negative
frequencies in the electron-phonon.out
i can't explain why i get negatives frequencies
Kindly suggest me the possible ways where I can solve this.
cordially

-- 
H.ZAARI
PhD Student in laboratory of magnetism and physics of high energy
Faculty of Sciences in Rabat - Morocco
Email:
* halimazaari at gmail.com <boujnah.mourad at gmail.com>*
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