<div>Dear Pw_forum,</div>
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<div>I am confusing when using mass of the atomic species&nbsp;for relaxation. In the Doc/INPUT_PW, it was said that:</div>
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<div>Mass_X&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; REAL&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; : mass of the atomic species [amu: mass of C = 12]<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<strong><em>not used if calculation=&#39;scf&#39;,&#39;nscf&#39;, &#39;bands&#39;, &#39;phonon&#39;</em></strong></div>

<div><strong><em></em></strong>&nbsp;</div>
<div>So for &nbsp;VCS&nbsp;calculation, which is better when using&nbsp;this parameter?</div>
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<div>---------------------------------------------------------------------------------<br>Phung Viet Bac<br>Division of Mathematical and Physical Science,<br>Graduate School of Natural Science and Technology,<br>Kanazawa University,<br>
Kakuma, Kanazawa 920-1192, JAPAN<br>TEL: +81-76-264-5492<br>FAX: +81-76-264-6065<br>E-mail: <a href="mailto:vietbac@wriron1.s.kanazawa-u.ac.jp">vietbac@wriron1.s.kanazawa-u.ac.jp</a><br>-------------------------------------------------------------------------------- </div>