The ABINIT Users Mailing List ( CLOSED )

[Yusuke Iguchi <iguchi@coral.t.u-tokyo.ac.jp>]

Dear, Prasenjit Sen

I met a similar difficulty in convergece at the calculation of Si 
surface before.
At that time, it was converged by using a simple mixing.

Generally, the accelleration method such as Broyden mixing is fast but 
unstable since it supposes a smooth behavior of the energy in a given 
space.
Therefore, I always switch to a more stable simple mixing method when 
the convergence cannot be  reached by another smart method.
Although it costs several times of time as you may guessed, it is 
faster than unconverged calculations.

I show my input file for Si(100) P(2x1) .

iscf=2 represents the simple mixing method and diemix controls the 
degree of mixing.

I hope you find it informative.

Best regards,
Yusuke IGUCHI.

---------------beginning of input file--------------
occopt 4
tsmear 0.01

ecut    6
ecutsm  0.1

kptopt  1
ngkpt   3 6 1

ionmov 5
iprcfc 1
ntime 40
tolmxf 5.0d-4
prtgeo 1

iscf   2
diemix 0.5
nstep  60
toldfe 1.0d-6

ntypeat 1
znucl   14

natom 24
typat 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
acell 14.514225 7.257112 41.052427
rprim     1.000000000000    0.000000000000    0.000000000000
          0.000000000000    1.000000000000    0.000000000000
          0.000000000000    0.000000000000    1.000000000000
      xred    1.5535586130E-01  0.0000000000E+00  3.1181419291E-01
              4.3938108714E-01  0.0000000000E+00  2.7982668639E-01
              1.1993405498E-02  5.0000000000E-01  3.4460880224E-01
              4.8389604800E-01  5.0000000000E-01  3.4319546729E-01
              2.5533986209E-01  5.0000000000E-01  4.1503262880E-01
              7.4715548326E-01  5.0000000000E-01  4.0090292677E-01
              2.4554742920E-01  0.0000000000E+00  4.7581021353E-01
              7.5197587707E-01  0.0000000000E+00  4.6465791321E-01
              9.9047399686E-01  0.0000000000E+00  5.3382398078E-01
              5.0687513737E-01  0.0000000000E+00  5.3031443544E-01
             -5.8234745565E-03  5.0000000000E-01  5.9621456457E-01
              5.0583752379E-01  5.0000000000E-01  5.9186372714E-01
              2.5582347455E-01  5.0000000000E-01  6.5378543543E-01
              7.4416247620E-01  5.0000000000E-01  6.5813627286E-01
              2.5952600314E-01  0.0000000000E+00  7.1617601922E-01
              7.4312486263E-01  0.0000000000E+00  7.1968556456E-01
              4.4525707976E-03  0.0000000000E+00  7.7418978647E-01
              4.9802412293E-01  0.0000000000E+00  7.8534208679E-01
              9.9466013791E-01  5.0000000000E-01  8.3496737120E-01
              5.0284451673E-01  5.0000000000E-01  8.4909707323E-01
              2.3800659450E-01  5.0000000000E-01  9.0539119776E-01
              7.6610395199E-01  5.0000000000E-01  9.0680453271E-01
              9.4644138695E-02  0.0000000000E+00  9.3818580709E-01
              8.1061891285E-01  0.0000000000E+00  9.7017331361E-01

-----------------end of input file --------------