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<div class="" style="word-wrap:break-word; line-break:after-white-space">Dear QE developers and users,
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<div class="">I’m currently trying to compute the phonon dispersion of a 2d material with the vdw-df2-b86r functional. I have fully relaxed the structure and made sure that it is indeed a semiconductor (PBE gap > 3eV). However, the Electric Field Calculation
by ph.x does not reach convergence in 100 iterations.</div>
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<div class="">I’ve tried by varying alpha_mix (from 0.7 down to 0.2) and the nmix_ph (up to 20) parameters, but it didn’t solve my issue. I’m using norm conserving pseudos from pseudo-dojo. If the calculations are carried out without the vdW functional (i.e.
plain PBE) the same calculation converges very quickly without any problem.</div>
<div class="">Am I possibly missing something? Any help would be appreciated!</div>
<div class="">Best,</div>
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<div class="">Michele</div>
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<div>--<br class="">
Michele Re Fiorentin, PhD<br class="">
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Department of Applied Science and Technology (DISAT) <br class="">
Politecnico di Torino <br class="">
corso Duca degli Abruzzi 24, 10129 Torino (Italy)</div>
<div>tel: +39 0110904333</div>
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