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<p>Dear Stefano, thank you for your answer. <br>
</p>
<p><br>
</p>
<p>Converting the values I get:</p>
<p>2.93 GPa = 29.3 kbar (Ry/Bohr^3)</p>
<p>120.51 A^3 = 813.24 Bohr^3 <br>
</p>
<p>P*V = 23827.932 Ry</p>
<p><span>E(fit) = -181.23269 Ry</span></p>
<p><span>enthalpy = -181.23269+23827.932 =<span>23646,70536041</span> Ry</span><br>
</p>
<p><br>
</p>
<p>It is something very stupid that I can't see where am I doing wrong.</p>
<p><br>
</p>
<p>Another question is regarding the chisq , what should be a reasonable value? <br>
</p>
<p><br>
</p>
<p>Best</p>
<p>Inna<br>
</p>
<p><br>
</p>
</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Stefano de Gironcoli <degironc@sissa.it><br>
<b>Sent:</b> 08 May 2020 09:29:58<br>
<b>To:</b> users@lists.quantum-espresso.org<br>
<b>Subject:</b> Re: [QE-users] How ev.x calculate enthalpy?</font>
<div> </div>
</div>
<div>
<p><tt>dear Inna,</tt></p>
<p><tt><br>
</tt></p>
<p><tt> in the output file energies and enthalpies are written in Ry, volumes in A^3 and pressures in GPa</tt></p>
<p><tt> in order to apply directly the enthalpy formula everything should be given with consistent units.</tt></p>
<p><tt> if you check the ev.f90 code (in PW/tools) there are unit conversion factors when using the pressure</tt></p>
<p><tt><br>
</tt></p>
<p>line 304: epv(i) = etot(i) + p(i)*v0(i) / ry_kbar<br>
</p>
<p><br>
</p>
<p> and when printing the volume</p>
<p><br>
</p>
<p>lines 350-352:</p>
<p> WRITE(iun,'(f8.2,2x,f12.5, 2x,f12.5, f12.5, 3x, f8.2, 3x,f12.5)') &<br>
( v0(i)*bohr_radius_angs**3, etot(i), efit(i), &<br>
etot(i)-efit(i), p(i)/gpa_kbar, epv(i), i=1,npt )</p>
<p><br>
</p>
<p> best</p>
<p><br>
</p>
<p>stefano<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 08/05/20 09:01, Inna Nangoi wrote:<br>
</div>
<blockquote type="cite" cite="mid:03251a7a2bb346d8b64c90e7d8d4ebc0@mmk.su.se"><style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
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<div>Hi, <br>
</div>
<div>I can't figure out how ev.x calculate enthalpy. I checked the ev.f90 and found out that
<br>
</div>
<div><span>Enth(i)=Efit(i)+Pfit(i)*V0(i) is the enthalpy (Ry)</span></div>
<div>But when I try to calculate by hand I don't reach the same value as reported in ev.x
<br>
</div>
<div>output file (see below) . For example, for V = <span>120.51</span> <br>
</div>
<div><span>Enth(i)=Efit(i)+Pfit(i)*V0(i)</span></div>
<div><span>Enth(i)= <span>-181.23265 </span>+ 2.93*120.51 = 171.86161</span><span>
<div><br>
</div>
</span><span></span><span></span><span></span>What am I doing wrong?</div>
<div><br>
</div>
<div># equation of state: murnaghan. chisq = 0.4329D-07<br>
# V0 = 996.51 a.u.^3, k0 = 92 kbar, dk0 = 4.10 d2k0 = 0.000 emin = -181.24780<br>
# V0 = 147.67 Ang^3, k0 = 9.2 GPa<br>
<br>
##########################################################################<br>
# Vol. E_calc E_fit E_diff Pressure Enthalpy<br>
# Ang^3 Ry Ry Ry GPa Ry<br>
##########################################################################<br>
<div> 124.13 -181.23698 -181.23704 0.00005 2.34 -181.10397<br>
120.51 -181.23265 -181.23269 0.00003 2.93 -181.07085</div>
<br>
Best</div>
<div>Inna Nangoi</div>
<div>Stockholm University /Universidade Federal de Juiz de Fora<br>
</div>
<br>
</div>
<br>
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