[Pw_forum] error in vc-md at 700K, 72GPa calculations

[WANG Wei]

Dear QE users,

I am new QE user. As a benchmark test, I want to simulate the hcp-to-bcc
pressure-induced transition in Mg at 700K, 72GPa using VC-MD method. But I
found the error occurs when I applied high pressure (72GP).

error info is:
##########################################################

  new lattice vectors (alat unit) :
           NaN           NaN           NaN
           NaN           NaN           NaN
           NaN           NaN           NaN
  new unit-cell volume =         NaN (a.u.)^3
  new positions in cryst coord
Mg               NaN           NaN           NaN
Mg               NaN           NaN           NaN
  new positions in cart coord (alat unit)
Mg               NaN           NaN           NaN
Mg               NaN           NaN           NaN

     Ekin =            NaN Ry    T =    NaN K  Etot =            NaN
     new unit-cell volume =          NaN a.u.^3 (         NaN Ang^3 )

CELL_PARAMETERS (alat=  6.07000000)
           NaN           NaN           NaN
           NaN           NaN           NaN
           NaN           NaN           NaN

ATOMIC_POSITIONS (crystal)
Mg               NaN           NaN           NaN
Mg               NaN           NaN           NaN



     Writing output data file pwscf.save

     first order wave-functions extrapolation
     Message from extrapolate_wfcs:
     the matrix <psi(t-dt)|psi(t)> has  6 small (< 0.1) eigenvalues
     Check: negative starting charge=         NaN
     first order charge density extrapolation
     NEW k-points:
        k(    1) = (         NaN         NaN         NaN), wk =   2.0000000
     Check: negative starting charge=         NaN

     total cpu time spent up to now is      2.30 secs

     per-process dynamical memory:     3.5 Mb

     Self-consistent Calculation

     iteration #  1     ecut=    25.00 Ry     beta=0.70
     Davidson diagonalization with overlap

##########################################################

This is my parameters for the calculations:


 &CONTROL
   calculation =   "vc-md"   ,
   restart_mode = 'from_scratch' ,
   outdir='/home/wangvei/tmp/' ,
   pseudo_dir   = "/home/wangvei/works/quantum-espresso/pseudo",
   disk_io = 'default' ,
   verbosity = 'default' ,
   tstress = .true. ,
   tprnfor = .true. ,
   nstep =  300  ,
   etot_conv_thr = 1.0E-5  ,
   forc_conv_thr = 1.0D-4 ,
   iprint = 1 ,
   max_seconds = 6000 ,
   dt = 20 ,
 /
 &SYSTEM
   ibrav = 4 ,
   celldm(1)=6.07
   celldm(3)=1.6235
   nat  =  2 ,
   ntyp  =  1 ,
   ecutwfc  =  25.0 ,
   ecutrho  =  100.0 ,
!  nbnd  =  9 ,
   occupations  =  'smearing' ,
   smearing    = "gaussian",
   degauss     = 0.02D0,
   nosym=.true.
 /
 &ELECTRONS
   electron_maxstep  =  70  ,
   conv_thr  =  1.0d-7  ,
   diagonalization   =   'david'   ,
 /
 &IONS
    tempw=700.0D0,
    ion_temperature='rescale-T'
    delta_t=1.0
    pot_extrapolation='second-order'
    wfc_extrapolation='second-order'
 /
 &CELL
   cell_dynamics = 'pr' ,
   press = 72000000.0D0,    ! 72GPa
!   wmass =  0.02
   cell_factor=10,
 /
ATOMIC_SPECIES
Mg    24.0  Mg.pz-n-vbc.UPF
ATOMIC_POSITIONS crystal
Mg    0.33333   0.66667   0.25000
Mg    0.66667   0.33333   0.75000
K_POINTS automatic
  1 1 1   1 1 1

Sincerely yours
WANG
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20110630/c2eeee69/attachment.html>