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<div>Dear all users,
<BR>
<BR>
Now I've a question on the polar materials. In order to get LO-TO splitting, you know, we need to use dynmat.x. In the input file for dynmat.x, we need input q(1), q(2), and q(3), that is, the propagation direction. I don't know how to choose this direction. My system has hexagonal symmetry and its primitive cell is rhombohedral.
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Any suggestions are welcome. Thanks in advance.
<BR>
<BR>
Bests,
<BR>
<BR>
Yanling Li,
<BR>
<BR>
Institute of Solid states physics, CAS, P. R. China. </div>
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