Dear Denis,<br>Firstly you have to check your Phonon dos norm is coming correct or not???<br>I think there is a problem calculating with phonon frequency(Omega).<br>Here i am giving you a reference from where you can get the important clue.<br>
<br>""""First-principles calculations of phonon and thermodynamic properties<br>of AlRE (RE= Y, Gd, Pr, Yb) intermetallic compounds ∗<br>Rui Wang† Shaofeng Wang, and Xiaozhi Wu""""""<br>
,<br><br><br><br>Department of Physics and Institute for Structure and Function, Chongqing University,<br>Chongqing 400044, P. R. China.<br><br><br><div class="gmail_quote">On Mon, Jul 30, 2012 at 2:57 PM, DENIS MAGERO <span dir="ltr"><<a href="mailto:magerode@gmail.com" target="_blank">magerode@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear all,<br>I,m calculating thermodynamic properties using QHA for magnesium hydride. There is however a value of NaN for values of entropy and F_vibration. Could someone please help. <br>
<br>Attached is the file.<br>  <br>
# Zero vibration energy:      0.0053709107  (Ry/cell)<br># Phonon DOS norm      :      1.998766      ! 3N for check purpose, N number of atoms in the unit cell<br># T in K, F_vib in Ry/cell, C_v in R (the universal gas constant by 3N modes), S in k_B <br>

#<br>#   T         E_internal        F_vibration          Specific heat (C_v)       Entropy<br>############################################################################################################<br>    5.00      0.0053761511               NaN           0.0024038079                   NaN<br>

   10.00      0.0053762656               NaN           0.0048307667                   NaN<br>   15.00      0.0053764576               NaN           0.0073049072                   NaN<br>   20.00      0.0053767292               NaN           0.0098829693                   NaN<br>

   25.00      0.0053770872               NaN           0.0128304742                   NaN<br>   30.00      0.0053775527               NaN           0.0168191020                   NaN<br>   35.00      0.0053781734               NaN           0.0227957550                   NaN<br>

   40.00      0.0053790267               NaN           0.0316241179                   NaN<br>   45.00      0.0053802120               NaN           0.0438189128                   NaN<br>   50.00      0.0053818386               NaN           0.0594854231                   NaN<br>

   55.00      0.0053840137               NaN           0.0783989719                   NaN<br>   60.00      0.0053868337               NaN           0.1001298120                   NaN<br>   65.00      0.0053903795               NaN           0.1241557017                   NaN<br>

   70.00      0.0053947154               NaN           0.1499421117                   NaN<br>   75.00      0.0053998891               NaN           0.1769907068                   NaN<br>   80.00      0.0054059335               NaN           0.2048639362                   NaN<br>

   85.00      0.0054128686               NaN           0.2331939897                   NaN<br>   90.00      0.0054207041               NaN           0.2616824973                   NaN<br>   95.00      0.0054294410               NaN           0.2900952630                   NaN<br>

  100.00      0.0054390741               NaN           0.3182546901                   NaN<span class="HOEnZb"><font color="#888888"><br><br clear="all"><br>-- <br><div style="font-family:lucida console,sans-serif"><font size="3"><span><span><span>Dennis Magero,</span></span></span></font></div>

<div style="font-size:13px;background-color:transparent;font-family:lucida console,sans-serif"><font size="3"><span><span><span>M.Sc Student,<br>Computational group,<br></span></span></span></font></div><div style="font-size:13px;background-color:transparent;font-family:lucida console,sans-serif">

<font size="3"><span>Chepkoilel University College, ELDORET</span></font></div><div style="font-size:13px;background-color:transparent;font-family:lucida console,sans-serif"><font size="3"><span>KENYA.</span></font></div>

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<br></blockquote></div><br><br clear="all"><br>-- <br>Thanks and Regards<br>Bramha Prasad Pandey<br>Ph.D Student Indian School of Mines(ISM)<br>Dhanbad, INDIA.<br><br>