[Wien] Fwd: not getting convergence with MBJ potential

[shamik chakrabarti]

Dear wien2k users,

                       Any response of my previous mail will be very
helpful for us. Eagerly waiting for your comments.

with regards,

---------- Forwarded message ----------
From: shamik chakrabarti <shamikphy at gmail.com>
Date: Sun, Dec 11, 2011 at 5:42 PM
Subject: not getting convergence with MBJ potential
To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>


Dear wien2k users,

                       I am trying to simulate electronic structure of a
charge transfer insulator. Our system consists of a unit cell having 56
atoms and we are using 14 k-points. As GGA+U method was failed to reproduce
the proper band gap (in fact much less than the experimentally obtained
one) we have opted for MBJ potential. *Initially the mixing parameter was
set to 0.2 and we got Ghost band error after few iterations. Hence we
reduce the mixing parameter to 0.15.* Until now still it has shown no error
except some extra message in case.dayfile. I am giving those messages
below. So far e.c. & c.c were achieved up to 2.239... & 5.4599 respectively
and already 36 iterations are over. My questions are:

(1) Is it ok to set up a mixing parameter of 0.15 that is with it, is it
possible to reach convergence?

(2) As plain GGA takes around 80 iterations to converge, is it that MBJ
potential will take much higher than that as we know it is always hard to
get convergence with this method?

(3) what are the meanings of the given messages below:

  lapw2 -c -up   -vresp (17:12:13) >   lapw1  -c -dn     (16:19:33)
10848.369u 98.026s 52:39.78 346.4% 0+0k 0+1099920io 0pf+0w
>   lapw1  -c -up     (15:26:49) 10864.462u 99.082s 52:44.39 346.4% 0+0k
0+1100232io 0pf+0w
460.324u 151.313s 6:52.62 148.2% 0+0k 0+732368io 0pf+0w
 -5.956509016536202E-002
  3.325214690385789E-002 -9.166205529297161E-002 tauwrong=
 int:rho,tauw,grho,g2rho  2.146196813781874E-002  1.287982148952303E-002
 -4.564940741427861E-002
  3.061850458947012E-002 -5.357427363703868E-002 tauwrong=
 int:rho,tauw,grho,g2rho  1.778719641126464E-002  1.317651193616000E-002
     *what is tauwrong?*
 -4.561631481999567E-002
  3.051935798833875E-002 -5.372842413400847E-002 tauwrong=
 int:rho,tauw,grho,g2rho  1.783702549056333E-002  1.305474408433668E-002
 -2.872847342414767E-002
  2.625149916992486E-002 -2.271097056901070E-002 tauwrong=
 int:rho,tauw,grho,g2rho  1.456340274765583E-002  1.183001700580401E-002
 -2.843529510619935E-002
  2.607602777746414E-002 -2.279192386903682E-002 tauwrong=
 int:rho,tauw,grho,g2rho  1.462794826548238E-002  1.162089194449066E-002
 -1.211083415464120E-002
..........................................
..........................................
>   lapw0 (15:19:56)  sphere:rho,tauw,grho,g2rho   7.46875999972237
 180.956718336004
>   lapw0 -grr (15:15:10) 315.375u 93.253s 4:45.73 143.0% 0+0k
0+................


Any response in this regard will be very helpful for us. Thanks in advance.

with regards,
-- 
Shamik Chakrabarti
Senior Research Fellow
Dept. of Physics & Meteorology
Material Processing & Solid State Ionics Lab
IIT Kharagpur
Kharagpur 721302
INDIA



-- 
Shamik Chakrabarti
Senior Research Fellow
Dept. of Physics & Meteorology
Material Processing & Solid State Ionics Lab
IIT Kharagpur
Kharagpur 721302
INDIA
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