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<div><div>Dear All,</div><div><br></div><div>When doing a test of graphene by the tetrahedra_opt method, I fount it prints the complete negative frequencies if using the nq (6x6x1), while right for nq (6x6x2) but cost more times. </div><div><br></div><div>So, what's wrong? How to calculate the phonon of 2D materials by tetrahedra_opt method. Should the number of nq3 be larger than 1 for the tetrahedra_opt method? </div><div><br></div><div>Thanks.</div><div><br></div><div>Best regards,</div><div><br></div><div>Yipeng</div><div><br></div><div>Henan Normal University, Xinxiang China</div></div><div><br></div><div><br></div><div><br></div><!--😀-->
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