[QE-users] [Pw_forum] input file for isolated atom

[Ajmal Ghan]

Hello all,

I have gone through all the archived discussion about cohesive energy
calculation.

I am trying to calculate the cohesive energy of Ti which is  4.85eV. But I
am getting 5.23 eV which is closer. But I have found from a previous
discussion here (
https://www.mail-archive.com/users@lists.quantum-espresso.org/msg11410.html
)
<https://www.mail-archive.com/users@lists.quantum-espresso.org/msg11410.html>
that, the final magnetization should be 2 Bohr mag/ cell at the end of
calculation for Ti and smearing contribution of energy should be 0.0Ry.
But I am getting to get 3.83 Bohr mag/cell and a significant smearing
contribution = -0.03295688 Ry.

Anyone help me to sort this. what should I change in the input?


here is my input,

&control
   calculation      = 'scf'
   restart_mode     = 'from_scratch'
   pseudo_dir       = '/work/shared/s-tih/pseudo/'
   prefix           = 'Tifree_deg1_50_8k_1'
   wf_collect       = .true.
   tstress          = .true.
   tprnfor          = .true.
   forc_conv_thr    = 1.0d-6
   verbosity        = 'high'
 /
&system
   ibrav            = 1
   celldm(1)     = 20
   nat              = 1
   ntyp            = 1
   ecutwfc       = 50      //( I have performed convergence study. But
since degauss is reduced to 0.01, i increased ecut)
   ecutrho       = 400
   nspin          = 2
   starting_magnetization(1) = 1        // I think, the final magnetisation
should be 2 bohr mag/ cell at the end of calculation.
   nosym            = .true                    /// I hope this is enough to
break the symmetry
   nbnd             = 100
   occupations      = 'smearing',  smearing='mp', degauss=0.01D0
 /
&electrons
   diagonalization  = 'cg'
   mixing_beta      = 0.7d00
   conv_thr         = 1.0d-8     // I used even higher convergence since
smearing is reduced.
/
ATOMIC_SPECIES
  Ti  47.8670  Ti.pbe-spn-rrkjus_psl.1.0.0.UPF


ATOMIC_POSITIONS (crystal)
   Ti     0.5 0.5 0.5

K_POINTS {automatic}
  8  8  5  0  0  0


I don't really know this is the correct way to post a reply. All input is
welcome.

Thanks & Regards,
*------------------------------------------------------------------------------------------------------*
Ajmalghan MUTHALI

Post doctorate researcher
Laboratoire ICB
UMR 6303 CNRS-Université de Bourgogne
9 Avenue Alain Savary, BP 47870
F-21078 DIJON Cedex, France
Tel: +33-(0)7.69.28.19.91
Email : ajmalghan.muthali at u-bourgogne.fr
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