arm chair CNT cannot converge


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Hello!

Needless to say I am relatively new to NWChem software and also studying CNT.
I have a 10 Angs arm chair CNT. I am sure the structure is good. However , it does not convergence with the given criteria.
Any suggestions?


start CNT_AC_20
title "CNT arm chair 10 Angs with DFT B3LYP basis set"

scratch_dir /mnt/data2/gdey/nwchem/scratch
memory total 2400 mb

charge 0

geometry units angstroms print xyz
C        4.56836        3.21105        1.62497
C 5.02837 3.26593 0.17132
C 3.75007 4.56066 3.64292
C 3.82639 4.49503 2.08755
C 2.50508 4.71155 1.28039
C 2.74453 5.84166 0.27896
C 1.34063 4.53282 3.54992
C 1.21391 4.97420 2.09734
C -0.13406 4.47306 1.49982
C -0.38391 4.69224 0.01417
C -0.72078 3.17882 3.69079
C -0.72087 3.16771 2.10985
C -0.18994 1.83028 1.53147
C -0.42782 1.61609 0.04144
C 1.32212 1.78761 3.54178
C 1.18983 1.38443 2.08068
C 2.41082 1.85596 1.26622
C 2.54767 0.96832 0.02968
C 3.71946 1.84274 3.57892
C 3.77768 1.93209 2.02298
C 4.01913 3.16811 5.84402
C 4.00343 3.18411 4.31302
C 3.32580 4.32434 7.90157
C 2.98323 4.07393 6.44047
C 2.46887 5.32347 5.72168
C 2.48853 5.26531 4.18097
C 1.03936 5.59047 7.87240
C 1.02883 5.58695 6.29146
C 0.01336 4.52207 5.75442
C -0.02182 4.47365 4.22783
C -0.08083 3.19214 7.88490
C 0.37810 3.20802 6.43233
C 0.03619 1.88995 5.80128
C -0.02521 1.89067 4.26057
C 1.18218 0.85560 7.89470
C 1.09619 0.90790 6.33933
C 2.48365 1.09231 5.66923
C 2.50373 1.08233 4.13823
C 3.60464 1.69391 7.95927
C 3.67162 1.77689 6.40332
C 4.14114 3.16154 9.95256
C 3.25465 3.01740 8.71603
C 2.60560 5.79124 9.94081
C 2.47540 5.49881 8.45078
C -0.30643 4.79889 9.96808
C -0.02076 4.62899 8.48243
C -0.43285 1.46838 9.70329
C 0.56795 2.04533 8.70186
C 2.72256 0.09226 9.81093
C 2.63261 0.54671 8.35728
H 5.62563 2.36411 -0.07729
H 4.18125 3.37176 -0.53480
H 3.66742 5.67336 -0.31222
H 1.91227 5.95447 -0.43588
H -1.42648 4.40527 -0.23632
H -0.28524 5.77111 -0.21976
H -1.49125 1.81953 -0.20285
H -0.20728 0.56228 -0.22778
H 3.32762 1.31527 -0.67165
H 2.76358 -0.08081 0.32498
H 4.05219 2.31255 10.65390
H 5.20564 3.28040 9.65727
H 2.08349 6.73975 10.18510
H 3.67599 5.90713 10.21003
H -0.35567 5.87912 10.21857
H -1.30200 4.37166 10.20201
H 0.01240 0.64266 10.29447
H -0.79732 2.22504 10.41813
H 3.76481 -0.19709 10.05954
H 2.36014 0.86521 10.51705
end

basis
   C library cc-pvdz
H library cc-pvdz
end

scf
maxiter 100
direct
end

dft
   iterations 2000
xc b3lyp
direct
end


task dft optimize

task scf freq numerical