<div>hello all, recently I calculated the phonon of bcc sodium using pw4.1.2, when I plot the phonon dispersion along high symmtry ,I meet a problem;</div>
<div>for bcc structure ,there are four high symmetry points in crystall coordinations : </div>
<div><strong>G:(0,0,0) <span lang="EN-US" style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: ËÎÌå; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">H</span></strong><span lang="EN-US" style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: ËÎÌå; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><strong>(1/2,-1/2,1/2 ) P:(1/4,1/4,1/4) N: (0,0,1/2 )</strong></span></div>
<div><span lang="EN-US" style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: ËÎÌå; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><strong></strong></span>and the pwscf give the following bcc basis</div>
<div> crystal axes: (cart. coord. in units of a_0)<br> a(1) = ( 0.500000 0.500000 0.500000 )<br> a(2) = ( -0.500000 0.500000 0.500000 )<br> a(3) = ( -0.500000 -0.500000 0.500000 )</div>
<div>reciprocal axes: (cart. coord. in units 2 pi/a_0)<br> b(1) = ( 1.000000 0.000000 1.000000 )<br> b(2) = ( -1.000000 1.000000 0.000000 )<br> b(3) = ( 0.000000 -1.000000 1.000000 )</div>
<div>and I turn the high symmetry points into 2 pi/a units using pwscf ,then the four high symmetry points became :</div>
<div><strong> G :(0,0,0) ,H</strong> <strong>( 1.00 -1.00,1.00), P(0.00,0.00, 0.50),N(0.00, -0.50, 0.50)</strong><br> I plot the phonon dispersion along the high symmetry <strong>H-P-G-H-N-P-N-G, </strong>the results is obivously wrong, which differ the results from others ,I am sure the phonon calculations does not have problem , the problem is to how to get the correct the symmetry lines.</div>
<div> and I also found if I use the following high symmetry points directly ,then the results is OK</div>
<div><strong> G :(0,0,0) ,H</strong> <strong>( 0.00 1.00,0.00), P(0.5,0.5, 0.50),N(0.5, 0.5, 0.00)</strong></div>
<div>then I feel puzzled, would some one give some idea about this?</div>
<div>any help will be appreciated<br clear="all"><br>-- <br>ZhouDawei<br>JiLin Universiyt ,ChangChun ,China<br><a href="mailto:zdw2000@gmail.com">zdw2000@gmail.com</a><br></div>