<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">Also said “small group” of the q vector. Please take the time to spend a couple of hours in the nearest library and look for some texts in group theory or “traditional” electronic-structure theory (Bassani and Pastori Parravicini would do). Make sure you understand what you read. If you don’t, try harder. Then revert to us, if need be. SB<br><br><div id="AppleMailSignature">--<div>Stefano Baroni, Trieste -- swift message written and sent on the go</div></div><div><br>On 11 Sep 2018, at 12:26, Anindya Bose <<a href="mailto:anindya@iiita.ac.in">anindya@iiita.ac.in</a>> wrote:<br><br></div><blockquote type="cite"><div>Dear Sir,<br>You are absolutely correct,I am getting exactly these symmetries.But transformation into D2h symmetries making the result incorrect and unphysical.Please tell me how to resolve this.<br>Thanks and regards,<br>Anindya Bose<br><br>On Tuesday, September 11, 2018, Paolo Giannozzi <<a href="mailto:p.giannozzi@gmail.com">p.giannozzi@gmail.com</a>> wrote:<br>> These symmetries?<br>> Calculation of q = 0.0000000 0.0000000 0.0000000<br>> Mode symmetry, D_6h(6/mmm) point group<br>> Calculation of q = 0.0000000 0.1443376 0.0000000<br>> Mode symmetry, C_2v (mm2) point group<br>> Calculation of q = 0.0000000 0.2886751 0.0000000<br>> Mode symmetry, C_2v (mm2) point group<br>> Calculation of q = 0.0000000 0.4330127 0.0000000<br>> Mode symmetry, C_2v (mm2) point group<br>> Calculation of q = 0.0000000 -0.5773503 0.0000000<br>> Mode symmetry, D_2h (mmm) point group<br>> Calculation of q = 0.1250000 0.2165064 0.0000000<br>> Mode symmetry, C_2v (mm2) point group<br>> "Mode symmetry" means symmetry subgroup that leaves that wave-vector q unchanged.<br>><br>><br>> On Tue, Sep 11, 2018 at 9:02 AM, Anindya Bose <<a href="mailto:anindya@iiita.ac.in">anindya@iiita.ac.in</a>> wrote:<br>>><br>>> Dear Experts,<br>>> While doing the phonon calculation of Graphene,I am getting a symmetry error in my ph.out files.Initially the file ph.out showing the correct symmetry of the material(e.g. Graphene D_6h point group symmetry) but after some interval it is showing some erroneous point group symmetry D_2h.I am very much confused with this absurd result.What should I do here?I have played with conv_threshold (tried to reduce)but I was unsuccessful.How can I resolve this problem? A copy of ph.out file is enclosed with this mail. I will be waiting for a positive suggestion.<br>>> Thanks and regards,<br>>> Anindya Bose<br>>> Research Fellow,<br>>> Indian Institute of Information Technology,Allahabad<br>>><br>>> _______________________________________________<br>>> users mailing list<br>>> <a href="mailto:users@lists.quantum-espresso.org">users@lists.quantum-espresso.org</a><br>>> <a href="https://lists.quantum-espresso.org/mailman/listinfo/users">https://lists.quantum-espresso.org/mailman/listinfo/users</a><br>><br>><br>><br>> --<br>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>> Phone +39-0432-558216, fax +39-0432-558222<br>><br>>
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