On 02/09/2024 17:32, RAQUEL YANES RODRIGUEZ wrote:
it appears that B0 should be around 40-50 GPa. However, I am obtaining a
value of 5 GPa
The obtained values of volume (where V=a^2*c) and total energy are:
Vol (ang^3) Total energy (eV)
28.640500 -89.84334
33.836204 -89.93096
36.654496 -89.95390
39.625092 -89.96478
42.752000 -89.96531
46.039228 -89.95738
49.490784 -89.94272
56.902912 -89.89999
65.020448 -89.84715
So, I put those numbers into a file mgh2.dat and run ~/q-e/bin/ev.x:
Lattice parameter or Volume are in (au, Ang) > Ang
Assuming Angstrom
Enter type of bravais lattice (fcc, bcc, sc, noncubic) > noncubic
Enter type of equation of state :
1=birch1, 2=birch2, 3=keane, 4=murnaghan > 4
Input file > mgh2.dat
Minimization succeeded
Output file > mgh2.dat
Beware: file mgh2.dat will be overwritten
The contents of file 'mgh2.dat':
# equation of state: murnaghan. chisq = 0.1905D-05
# V0 = 278.49 a.u.^3, k0 = 745 kbar, dk0 = 3.76 d2k0 = 0.000
emin = -89.96467
# V0 = 41.27 Ang^3, k0 = 74.6 GPa
##########################################################################
# Vol. E_calc E_fit E_diff Pressure Enthalpy
# Ang^3 Ry Ry Ry GPa Ry
##########################################################################
28.64 -89.84334 -89.84281 -0.00053 58.46 -89.07520
33.84 -89.93096 -89.93301 0.00205 22.01 -89.58937
36.65 -89.95390 -89.95399 0.00009 11.14 -89.76660
39.63 -89.96478 -89.96348 -0.00130 3.27 -89.90528
42.75 -89.96531 -89.96381 -0.00150 -2.47 -90.01369
46.04 -89.95738 -89.95672 -0.00066 -6.69 -90.09865
49.49 -89.94272 -89.94351 0.00079 -9.82 -90.16562
56.90 -89.89999 -89.90241 0.00242 -13.91 -90.26305
65.02 -89.84715 -89.84580 -0.00135 -16.25 -90.33175
The bulk modulus (k0) seems to be around 75 GPa
According to literature, the total energy should be around -17.822 eV
The total energy in a pseudopotential calculation depends upon the
pseudopotential
Paolo
after optimization. However, my values are around -89 eV (-6.61 Ry). I
cannot find where the problem lies. I have verified that ecutwfc,
ecutrho, and the k-points are converged. I can’t think of what else to
do. Could someone please verify the total energy of this structure or
guide me on where the issue might be?
Thank you in advance!
--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216
X SCUOLA ENERGIE RINNOVABILI 16-21/9/2024 - PRE-ISCRIZIONE
https://agenda.infn.it/event/39573/
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