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[yukihiro_okuno@fujifilm.co.jp]

Dear Abinit Users.

I'm now testing the calculation of fcc-lattice 
of the Pb for lattice optimization.

I use Teter's extended norm-conserving pseudo 
potential which I downloaded from the ABINIT site.

The results and calculation depends on the initial 
guess of acell or scaling of relation of the acell 
and rprim.

On the initial acell, 

 I had first sets acell = 9.3548995339E+00 ( corresponds 
 latticd constant of the fcc cube), the calculation of 
 the results failed with the massage 
 BROYDEN STEP NUMBER   3  
------------------------------------------------------

 metric : ERROR -
  Current rprimd gives negative (R1xR2).R3 .
  Rprimd =    0.000000E+00   -1.073389E-01   -1.073389E-01
             -1.073389E-01    0.000000E+00   -1.073389E-01
             -1.073389E-01   -1.073389E-01    0.000000E+00

 and, if  I set acell = 10.00 I can get the conversed 
 results. 

  But the conversed results is that acell = 1.0345762121E+01 
  which is rather larger than the experimental vales, 
  a = 9.353198.  Basically is the origin of the discrepancy 
  due to the pseudo-potential of lead ? 

  And On the scaling relation of acell and rprim, I set 
  acell = a/sqrt(2), and rprim = 0, 1/sqrt(2), 1/sqrt(2) 
  ( for example),  the calculation is also failed with the 
   message, ( in this case I set rather small value of dilatmx)

The new primitive vectors rprimd (an evolving quantity)
  are too large with respect to the old rprimd and the accompanying dilatmx :
  this large change of unit cell parameters is not allowed by the present 
value of dilatmx.
  You need at least dilatmx=    1.657208E+00) 

  I use ABINIT-4.2.3 on the DOS/WIn-Intel-PGI version. 

  Sincerely, 

   Yukihir Okuno.


The results of the lattice optimization of fcc-Pb crystal 
with Teter's pseudo potential.  the experimental 
value of the lattice constant of fcc cube is 9.353198.    

-outvars: echo values of variables after computation  --------
     acell    1.0345762121E+01  1.0345762121E+01  1.0345762121E+01 Bohr
       amu    2.07200000E+02
    diemac    1.20000000E+01
   dilatmx    2.00000000E+00
      ecut    4.00000000E+01 Hartree
    ecutsm    5.00000000E+00 Hartree
    etotal   -5.9806901453E+01
     fcart    0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
    ionmov         2
       ixc         3



Here is my input file.

#Definition of the unit cell
optcell 1
ionmov 2
ntime 20
dilatmx 2.0 
ptrwf 0

acell 10.0 10.0 10.0 

rprim     0.000000000000     0.5     0.5
          0.5     0.000000000000     0.5
          0.5     0.5     0.000000000000

ntypat    1 
znucl 82 
natom    1 
typat 1 
xcart 
    0.000000000000     0.000000000000     0.000000000000 

tsmear 0.04 
kptopt 1
ngkpt 8 8 8
ecut 40 
ecutsm 5.0
ixc 3 
nstep 10 
toldff 1.0d-7
diemac 12.0