On Fri, May 8, 2020 at 10:07 AM Inna Nangoi <inna.nan...@mmk.su.se> wrote:
2.93 GPa = 29.3 kbar (Ry/Bohr^3) > 1 kbar is not 1 Ry/Bohr^3 Paolo ------------------------------ > *From:* users <users-boun...@lists.quantum-espresso.org> on behalf of > Stefano de Gironcoli <degir...@sissa.it> > *Sent:* 08 May 2020 09:29:58 > *To:* users@lists.quantum-espresso.org > *Subject:* Re: [QE-users] How ev.x calculate enthalpy? > > > dear Inna, > > > in the output file energies and enthalpies are written in Ry, volumes in > A^3 and pressures in GPa > > in order to apply directly the enthalpy formula everything should be > given with consistent units. > > if you check the ev.f90 code (in PW/tools) there are unit conversion > factors when using the pressure > > > line 304: epv(i) = etot(i) + p(i)*v0(i) / ry_kbar > > > and when printing the volume > > > lines 350-352: > > WRITE(iun,'(f8.2,2x,f12.5, 2x,f12.5, f12.5, 3x, f8.2, > 3x,f12.5)') & > ( v0(i)*bohr_radius_angs**3, etot(i), efit(i), & > etot(i)-efit(i), p(i)/gpa_kbar, epv(i), i=1,npt ) > > > best > > > stefano > > > On 08/05/20 09:01, Inna Nangoi wrote: > > Hi, > I can't figure out how ev.x calculate enthalpy. I checked the ev.f90 and > found out that > Enth(i)=Efit(i)+Pfit(i)*V0(i) is the enthalpy (Ry) > But when I try to calculate by hand I don't reach the same value as > reported in ev.x > output file (see below) . For example, for V = 120.51 > Enth(i)=Efit(i)+Pfit(i)*V0(i) > Enth(i)= -181.23265 + 2.93*120.51 = 171.86161 > > What am I doing wrong? > > # equation of state: murnaghan. chisq = 0.4329D-07 > # V0 = 996.51 a.u.^3, k0 = 92 kbar, dk0 = 4.10 d2k0 = 0.000 emin > = -181.24780 > # V0 = 147.67 Ang^3, k0 = 9.2 GPa > > ########################################################################## > # Vol. E_calc E_fit E_diff Pressure Enthalpy > # Ang^3 Ry Ry Ry GPa Ry > ########################################################################## > 124.13 -181.23698 -181.23704 0.00005 2.34 -181.10397 > 120.51 -181.23265 -181.23269 0.00003 2.93 -181.07085 > > Best > Inna Nangoi > Stockholm University /Universidade Federal de Juiz de Fora > > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list > users@lists.quantum-espresso.orghttps://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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