arm chair CNT cannot converge

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Posts 13
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

Forum Vet
Threads 10
Posts 1618
smearing
The only way to converge nanotubes is by using smearing

http://www.nwchem-sw.org/index.php/Release65:Density_Functional_Theory_for_Molecules#SMEAR...

dft
   iterations 2000
   xc b3lyp
   direct
   smear
end
Edited On 10:54:04 AM PDT - Tue, Sep 22nd 2015 by Edoapra

Clicked A Few Times
Threads 8
Posts 13
this does not work
Hello!

The problem I am facing is that the CNT collapses and the C and the H comes as separate atoms even after using the smearing. Is there any other way to get it done.

Regards
G


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