<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div>
<div style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman,new york,times,serif"> Atomic displacements:<br> There are 16 irreducible representations <br> <br> Representation 1 2 modes - To be done <br>
Phonon polarizations are as follows: </div></div></blockquote>
<div> mode # 1 mode # 2<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( -0.70711 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( -0.70711 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.70711 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.70711 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br> ( 0.00000 0.00000 ) ( 0.00000 0.00000 )<br>
( 0.00000 0.00000 ) ( 0.00000 0.00000 </div>
<div> </div>
<div> </div>
<div> I wander how the atoms ,in the unit cell are displaced, for a real calculation </div>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div>
<div style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman,new york,times,serif"><span id=""></span> what's the relation between polariztion vector and atoms displacements </div></div></blockquote>
<div> and the relation between phonon mode , how to use the symmetry group to </div>
<div> get the atoms displacements pattern , if the crystal have inversion symmetry ,</div>
<div> so is it correct to say a particular phonon mode have or not have inversion symmetry. </div>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div>
<div style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman,new york,times,serif"><span id=""></span><br>-- <br>Sincerely Y. M. Qian <br>Lab.of Condensed Matter Theory and Materials Computation <br>Institute of Physics <br>
Chinese Academy of Sciences<br>Tel: + 8610 8264 9147<br><a href="mailto:E-Mail%3Ayuminqian@gmail.com">E-Mail:yuminqian@gmail.com</a> <br>P.O.Box 603 Beijing 100190<br>China <br><br></div></div></blockquote></div>