Hi 
 
I would like to perform a geometry optimization of a quite large system. I'm getting this error after several hours of running: 
[[File: 
  
driver: task_gradient failed        0 
------------------------------------------------------------------------ 
------------------------------------------------------------------------ 
 current input line : 
  139:  task dft optimize 
------------------------------------------------------------------------ 
------------------------------------------------------------------------ 
 
]] 
I guess this error comes from the fact that after 400 iterations the calculation did not converged. (although the integrated energy is not too far from the threshold I think) Which possibilities are available to avoid that problem? 
(I have to say that is my first time using NWChem/6.0 )  
 
The input looks like: 
 
[[File: 
start ZnO102.nw 
 
title " SCF geometry optimization" 
set geometry:actlist 1:58 
geometry noautoz 
C                 15.61693561    7.52673614   34.99168772 
C                 16.50777789    6.56286593   35.43699734 
S                 15.95533612    9.04085619   35.79846122 
C                 14.54927585    7.34057802   34.04427977 
C                 17.42705997    7.02802126   36.39012240 
H                 16.49218006    5.54166388   35.06345007 
C                 17.27377659    8.36220055   36.70965177 
C                 13.78037816    8.24763001   33.31969494 
S                 14.09806690    5.70256408   33.66132085 
 
. 
. 
. 
O                 24.52696241   11.39622069   26.12607905 
Zn                22.90196241   12.33422069   26.93307905 
O                 22.90196241   14.21022069   26.12607905 
Zn                21.27696241   15.14822069   26.93307905 
O                 21.27796241   17.02422069   26.12607905 
Zn                27.77496241    9.52122069   26.93307905 
Zn                26.15096241   12.33422069   26.93307905 
Zn                24.52596241   15.14822069   26.93307905 
Zn                22.90196241   17.96222069   26.93307905 
 
 
end 
basis 
  Zn library LANL2DZ_ECP 
  O library Stuttgart_RLC_ECP 
  C library 3-21g 
  S library Stuttgart_RLC_ECP 
  H library 3-21g 
 
end 
ecp 
  Zn library LANL2DZ_ECP 
   O library Stuttgart_RLC_ECP 
   S library Stuttgart_RLC_ECP 
 
end 
dft 
  iterations 400 
 
end 
task dft optimize 
 
 
]] 
 
the output does the 400 iterations and the last 20 os so have the same integrated energy (Shown are the last 5): 
 
[[File:d= 0,ls=0.5,diis   396  -3380.2655940465 -3.79D-06  2.63D-06  6.49D-06  4634.1 
WARNING: error on integrated density =  0.32D-05 
greater than required accuracy of  0.10D-05 
d= 0,ls=0.5,diis   397  -3380.2655973522 -3.31D-06  2.39D-06  9.85D-06  4648.2 
WARNING: error on integrated density =  0.32D-05 
greater than required accuracy of  0.10D-05 
d= 0,ls=0.5,diis   398  -3380.2656006808 -3.33D-06  2.49D-06  1.19D-05  4658.2 
WARNING: error on integrated density =  0.32D-05 
greater than required accuracy of  0.10D-05 
d= 0,ls=0.5,diis   399  -3380.2656043009 -3.62D-06  2.44D-06  1.29D-05  4674.4 
WARNING: error on integrated density =  0.32D-05 
greater than required accuracy of  0.10D-05 
d= 0,ls=0.5,diis   400  -3380.2656078752 -3.57D-06  2.38D-06  1.38D-05  4682.0 
WARNING: error on integrated density =  0.32D-05 
greater than required accuracy of  0.10D-05 
 
 
     Calculation failed to converge 
     ------------------------------ 
        Total DFT energy =    -3380.265611647519 
           . 
           . 
           . 
                    DFT Final Molecular Orbital Analysis 
                      ------------------------------------ 
 
 
Vector   27  Occ=2.000000D+00  E=-9.733423D+00 
             MO Center= -8.1D+00, -1.3D+00,  4.8D+00, r^2= 3.1D-02 
  Bfn.  Coefficient  Atom+Function         Bfn.  Coefficient  Atom+Function 
 ----- ------------  ---------------      ----- ------------  --------------- 
  264      0.984507   42 C  s 
           . 
           . 
           .]]
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