The ABINIT Users Mailing List ( CLOSED )

[m-takahashi@hq.jp.nec.com]

Dear Yukihiro Okuno and ABINIT users

I think "occopt" option is needed for smearing of occupation numbers.

I modified your input file as follows;

---------------------------------------------------------
#Definition of the unit cell
optcell 1
ionmov 2
ntime 20
dilatmx 1.05 #changed
prtwf 0 
prtden 1
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 
nband 12 #changed
occopt 7 #changed
tsmear 0.04 
kptopt 1
ngkpt 8 8 8
ecut 40 # 1088 eV
ecutsm 0.5 #changed
ixc 3 
nstep 20
toldfe 1.0d-5 eV #changed
tolmxf 0.001 #changed
#toldff 1.0d-7
diemac 12.0
------------------------------------------------------

I obtained converged acell value of 9.3142013293E+00 bohr
 using Teter extended norm-conserving PP (available on ABINIT web site)
  with ABINIT v.4.2.3 for Windows. 

sincerely.

Masatake Takahashi


>
>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

----------------------------------
NEC Corp.
Masatake Takahashi
m-takahashi@hq.jp.nec.com
----------------------------------