[Pw_forum] S matrix not positive definite

[farouk boutaiba]

Dear all;

I am trying to calculate band gap of ZnSe in hexagonal phases including spin orbite interaction, using the approximation LDA-1/2.

I started with a pseudo-relativistic: Zn.rel-pz-dn-rrkjus_psl.0.2.2.UPF and Se.rel-pz-n-rrkjus_psl.0.2.UPF.
the scf calculation stop with following error: 

iteration #  1     ecut=    80.00 Ry     beta=0.70
Davidson diagonalization with overlap

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Error in routine cdiaghg (263):
S matrix not positive definite
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

stopping ...

the input file is:

&control
calculation='scf'
restart_mode='from_scratch',
tstress = .true.
tprnfor = .true.
prefix='znse-2h',
pseudo_dir = '/home/espresso-5.0.1/pseudo/',
outdir='/home/tmp/'
nstep= 3
/
&system
ibrav=  4, celldm(1) =7.437,celldm(3) =1.642, nat=  4, ntyp= 2,
ecutwfc =80.0,
lspinorb=.true.,
noncolin=.true.,
starting_magnetization=0.0,
occupations='smearing',
degauss=0.02,
smearing='mp',
ecutrho =600.0,
/
&electrons
diagonalization='david'
conv_thr =1.0e-7
mixing_beta = 0.7
/
ATOMIC_SPECIES
Zn  65.38  Zn.LDA.1.665.UPF
Se  78.96  Se.LDA.3.42.UPF
ATOMIC_POSITIONS crystal
Zn  0.00000000 0.00000000 0.00000000 
Zn  0.33333333 0.66666667 0.50000000 
Se  0.00000000 0.00000000 0.37500000 
Se  0.33333333 0.66666667 0.87500000 
K_POINTS (automatic)
8 8 6 1 1 1


Thanks in advance.



BOUTAIBA Farouk
Department of Physics

Faculty of Science

University of Science and Technology of Oran
Oran Algeria
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