Yambo Community Forum

Dear developers,
I have calculate the phonons under the input file od 02ph.in, but the lowest 3 branches are negative at gamma point. Does this affect the final
results? If so, how could we avoid it.
Thanks!

Hi,
the example for phonons in yambopy is a non-converged test. Therefore the user must check the convergence parameters for getting reliable results. In addition, the acoustic phonons, the 3 lowest branches at gamma can have negative values. One solution is to apply the acoustic sum rule with the functions designed for that in Quantum Espresso (dynmat.x).

Best,

Alejandro


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