5
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My input file for the (221) $\ce{MoS2}$ monolayer was created through Cif2QE (QEtoolkit):

&CONTROL
  calculation='relax',
  restart_mode = 'from_scratch',
  prefix       = 'MoS2', 
  pseudo_dir='./',
  outdir       = './out', 
  verbosity='high',
  tprnfor=.true., 
  forc_conv_thr=1.0d-4,
  etot_conv_thr = 1d-6 
  nstep=50,
/
&SYSTEM
  ibrav= 0, 
  nat= 12, 
  ntyp= 2, 
  input_dft = 'pbe' 
  occupations = 'smearing', 
  smearing = 'gauss', 
  degauss = 1.0d-2,
  ecutwfc = 60, 
  ecutrho = 240,
/
&ELECTRONS
  conv_thr = 1.0d-6
  mixing_beta = 0.5d0
  diagonalization  ='cg'
/
&IONS
  ion_dynamics = 'bfgs',
/
ATOMIC_SPECIES
  Mo 95.94 Mo.pbe-spn-rrkjus_psl.1.0.0.UPF
  S 32.066 S.pbe-n-rrkjus_psl.1.0.0.UPF
CELL_PARAMETERS (angstrom)
    6.2800000000  0.0000000000  0.0000000000
  -3.1400000000  5.4386395358  0.0000000000
   0.0000000000  0.0000000000 27.5300010000
ATOMIC_POSITIONS (crystal)
   S  0.3333330000  0.1666670000  0.1250000000
   S  0.8333330000  0.1666670000  0.1250000000
   S  0.3333330000  0.6666670000  0.1250000000
   S  0.8333330000  0.6666670000  0.1250000000
  Mo  0.1666670000  0.3333330000  0.2500000000
  Mo  0.6666670000  0.3333330000  0.2500000000
  Mo  0.1666670000  0.8333330000  0.2500000000
  Mo  0.6666670000  0.8333330000  0.2500000000
   S  0.3333330000  0.1666670000  0.3750000000
   S  0.8333330000  0.1666670000  0.3750000000
   S  0.3333330000  0.6666670000  0.3750000000
   S  0.8333330000  0.6666670000  0.3750000000
K_POINTS {automatic}
  4 4 1 0 0 0

In the output file, I got a warning:

WARNING: bfgs curvature condition failed, but it get relaxed.

Why am I getting this warning message? Is there any other tag I have to add to my input file (supercell)?

Output file

Improve this question
$\endgroup$
13
  • 3
    $\begingroup$ +1. Welcome to our new community and thank you for contributing your question here! We are very happy to see you here and hope to see much more of you in the future!!! Please do take a look at the edit that I made and keep these points in mind when you post here in the future. About your warning message: BFGS is an iterative optimization algorithm which involves derivatives. "curvature condition failed" suggests that a bad 2nd derivative (likely energy w.r.t. a geometrical coordinate). Please show the full output file. $\endgroup$
    – Nike Dattani
    Jun 29, 2021 at 17:57
  • $\begingroup$ Also, was it just a warning? Its definitely good to investigate warnings, but the calculation may have worked once it relaxed the curvature condition. $\endgroup$
    – Tyberius ♦
    Jun 29, 2021 at 18:09
  • $\begingroup$ I dont' know how to attach my output file. How to attach? $\endgroup$
    – Nithyadevi
    Jun 29, 2021 at 18:54
  • 1
    $\begingroup$ If your output file has fewer than 30,000 characters, please insert it exactly like you inserted your input file. If it's longer than that (you can test it by trying to copy-paste it into the question first, and if it doesn't work then you know it's too long) then if you let me know your GitHub username I can help you upload the question to our Git repository: github.com/HPQC-LABS/Modeling_Matters $\endgroup$
    – Nike Dattani
    Jun 29, 2021 at 19:05
  • 2
    $\begingroup$ Just a reminder, is the negative value in the cell parameters correct? @Camps I assume you mean the -3.14? $\endgroup$
    – Nike Dattani
    Jul 12, 2021 at 7:05

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