Hi,
I'm a new user of NWChem. Therefore I'm trying to run some dummy systems to get my hand into it.
I'm trying with a CH4 molecule. For example, the following inputs work fine and nwchem finish successfully.
geometry noautoz noautosym
C 7.67039 10.29926 4.07353
H 7.63303 10.29931 5.15228
H 8.00346 11.27118 3.73943
H 8.30423 9.51459 3.64992
H 6.65039 10.11495 3.79618
end
charge 0
scratch_dir /home/marc/Documents/simbeyond/votca/tuto-gromcas/tuto7/rundir028/tmp/nwchem/id_1
start
basis
* library 3-21g
end
memory 1500 mb
dft
mult 1
print "ao overlap"
xc xpbe96 cpbe96
direct
noprint "final vectors analysis"
maxiter 100
end
task dft
However, the following code, which is identical except that the molecule is translated to a new position, fails to converge
geometry noautoz noautosym
C 7.02375 12.76341 11.24170
H 7.58887 13.56485 10.79067
H 6.45492 13.16440 12.06805
H 6.36312 12.23783 10.54583
H 7.78718 12.08897 11.57874
end
charge 0
scratch_dir /home/marc/Documents/simbeyond/votca/tuto-gromcas/tuto7/rundir028/tmp/nwchem/id_4
start
basis
* library 3-21g
end
memory 1500 mb
dft
mult 1
print "ao overlap"
xc xpbe96 cpbe96
direct
noprint "final vectors analysis"
maxiter 100
end
task dft
I tried to increase the number of iterations and played a bit around with convergence parameters, but I do not manage to get the scf loop to converge. How is it possible that this system which is almost identical to the previous one do not converge? What do I'm missing?
Thanks in advance for your help,
Marc Barbry
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