[QE-users] S matrix not positive - MgH2 system

[Paolo Giannozzi]

There is a small utility "bin/dist.x" that reads the input of a pw.x 
calculation, makes a few initial tests, then computes the interatomic 
distances. This is what such utility reports:

Fatal error:  30 overlapping atoms (see file dist.out)

File dist.out:
  Atom   1 and   2 overlap (with lattice translation)
  Atom   1 and   3 overlap (with lattice translation)
  Atom   1 and   4 overlap (with lattice translation)
  Atom   1 and   5 overlap (with lattice translation)
  Atom   1 and   6 overlap (with lattice translation)
  Atom   1 and   7 overlap (with lattice translation)
  Atom   1 and   8 overlap (with lattice translation)
  Atom   2 and   3 overlap (with lattice translation)
  Atom   2 and   4 overlap (with lattice translation)
  Atom   2 and   5 overlap (with lattice translation)
  Atom   2 and   6 overlap (with lattice translation)
  Atom   2 and   7 overlap (with lattice translation)
  Atom   2 and   8 overlap (with lattice translation)
  Atom   3 and   4 overlap (with lattice translation)
  Atom   3 and   5 overlap (with lattice translation)
  Atom   3 and   6 overlap (with lattice translation)
  Atom   3 and   7 overlap (with lattice translation)
  Atom   3 and   8 overlap (with lattice translation)
  Atom   4 and   5 overlap (with lattice translation)
  Atom   4 and   6 overlap (with lattice translation)
  Atom   4 and   7 overlap (with lattice translation)
  Atom   4 and   8 overlap (with lattice translation)
  Atom   5 and   6 overlap (with lattice translation)
  Atom   5 and   7 overlap (with lattice translation)
  Atom   5 and   8 overlap (with lattice translation)
  Atom   6 and   7 overlap (with lattice translation)
  Atom   6 and   8 overlap (with lattice translation)
  Atom   7 and   8 overlap (with lattice translation)
  Atom  12 and  13 overlap (with lattice translation)
  Atom  14 and  15 overlap (with lattice translation)

Paolo

On 8/26/24 14:38, RAQUEL YANES RODRIGUEZ wrote:
> [Non ricevi spesso messaggi di posta elettronica da 
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> 
> Dear Quantum Espresso users,
> 
> I’m trying to run a simple SCF calculation for a MgH₂ structure using
> Quantum ESPRESSO, but I keep encountering an "S matrix not positive
> definite" error. I’ve attempted several modifications to the input,
> but none have resolved the issue:
> 
> - Increase Ecutwfc and Ecutrho values
> - Increase number of k-points
> - Change the pseudopotential
> - Change from ibrav=6 to ibrav=0
> 
> I suspect that the problem might be related to the geometry of the
> structure, though it should be correct since it’s a well-known system.
> 
> The input i'm using is the following one:
> 
> ---------------------------------------------------------------------------------------------
> &CONTROL
> title = 'MgH2' ,
> calculation = 'scf' ,
> outdir = './' ,
> pseudo_dir = './' ,
> /
> &SYSTEM
> ibrav = 6,
> A = 4.48 ,
> C = 2.99 ,
> nat = 15,
> ntyp = 2,
> ecutwfc = 90 ,
> ecutrho = 400 ,
> input_dft = 'PBE'
> occupations = 'smearing'
> smearing = 'gaussian'
> degauss = 0.02
> /
> &ELECTRONS
> conv_thr = 1.0d-8
> /
> &IONS
> /
> ATOMIC_SPECIES
> Mg 24.3050 Mg.pbe-spnl-kjpaw_psl.1.0.0.UPF
> H 1.00000 H.pbe-kjpaw_psl.1.0.0.UPF
> ATOMIC_POSITIONS angstrom
> Mg 0.000000 0.000000 0.000000
> Mg 0.000000 0.000000 2.992537
> Mg 0.000000 4.476694 0.000000
> Mg 0.000000 4.476694 2.992537
> Mg 4.476694 0.000000 0.000000
> Mg 4.476694 0.000000 2.992537
> Mg 4.476694 4.476694 0.000000
> Mg 4.476694 4.476694 2.992537
> Mg 2.238347 2.238347 1.496269
> H 0.875516 3.601178 1.496269
> H 3.601178 0.875516 1.496269
> H 3.113863 3.113863 0.000000
> H 3.113863 3.113863 2.992537
> H 1.362831 1.362831 0.000000
> H 1.362831 1.362831 2.992537
> K_POINTS automatic
> 4 4 4 1 1 1
> ---------------------------------------------------------------------------------------------
> 
> Does anyone know how to solve this problem?
> 
> Thank you in advance! :)
> 
> 
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine Italy, +39-0432-558216