[QE-users] BEEF-vdW, RISM and nspin = 2: large energy fluctuations

[Tom Demeyere]

Dear users,

I am trying to calculate binding energies using the BEEF-vdW and the RISM formalism (QE-6.7), for this aim I need to compute different molecules (H2O, O2, …) in H2O with HCl 1M.

O2 shows large energy fluctuations when I ask for:

- input_dft: “BEEF-vdW”
- nspin = 2

(The calculation converges when asking for nspin = 0, or changing the functional to PBE.)

Typical output:

…

iteration #  8 
...
     total energy              =    -180.99829260 Ry
     estimated scf accuracy    <       0.00029814 Ry
…
iteration #  9 
...
     total energy              =    -151.60027495 Ry
     estimated scf accuracy    <       0.00021978 Ry
…
iteration # 10
     total energy              =    -139.03397732 Ry
     estimated scf accuracy    <       0.00010331 Ry
…

The calculation ends at some point with: “history already reset at previous step: stopping”, the final energy given is wrong.

Full input:

&CONTROL
  calculation = 'relax'
  etot_conv_thr = 1.0000000000d-05
  forc_conv_thr = 5.0000000000d-04
  pseudo_dir = '/work/e89/e89/td5g20/PseudoPotentials/'
  tprnfor = .true.
  verbosity = 'high'
  trism = .true.
/
&SYSTEM
  ecutwfc = 60, ecutrho = 480
  occupations = ‘smearing’, smearing = ‘fd’, degauss = 0.01
  ibrav = 1, A = 20
  ntyp = 1, nat = 2
  nosym = .true.
  input_dft = "BEEF-vdW"
/
&ELECTRONS
  conv_thr = 1.00D-12
  mixing_mode = ‘local-TF’,  mixing_beta = 0.2
/
&IONS
  ion_dynamics = "bfgs"
/
&RISM
  nsolv = 3  
  closure = 'kh'  
  tempv = 298.15
  ecutsolv = 160.0
  starting1d = 'zero'  
  rism1d_conv_thr = 1.0e-8  
  rism1d_maxstep = 100000  
  mdiis1d_size = 20  
  mdiis1d_step = 0.1
  starting3d = 'zero'
  rism3d_maxstep = 10000  
  rism3d_conv_thr = 1.0e-6  
  rism3d_conv_level = 0.5  
  mdiis3d_size = 20  
  mdiis3d_step = 0.8
  solute_lj(1) = 'none'
  solute_epsilon(1) = 0.1554
  solute_sigma(1) = 3.1660
/
ATOMIC_SPECIES
O   15.999 O.pbe-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS angstrom
O             1.6891044673        1.7570200245        0.6442147904
O             2.3377455327        0.7138399755        0.6439152096
K_POINTS gamma
SOLVENTS mol/L
H2O  -1.0  H2O.spc.MOL
H3O+  1.0  H3O+.aq.MOL
Cl-   1.0  Cl-.aq.MOL

Best regards,
Tom Demeyere