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.org
https://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
