My first recommendation is to run it with all the defaults:
driver
maxiter 500
end
basis spherical
P library Def2-SV(P)
C library Def2-SV(P)
H library Def2-SV(P)
end
dft
tolerances tight
iterations 100
xc becke88 1.0 lyp 1.0
direct
end
task dft optimize
After that, I'll need a full input deck to see what is going on.
Bert
Quote:Richard Apr 10th 3:21 pmI'm a beginner at nwchem and seem unable to optimize the geometry of a simple organic
molecule to 'tight' convergence criteria using blyp/dvp. With inputs like the one below it almost but never quite makes it - same story with fine and ultrafine grids. The HF version converges cleanly in ca 30 steps.
So it seems something needs to be tightened - can anyone give me a clue here?
Thanks
Richard
scf
thresh 1e-8
end
driver
eprec 1e-8
gmax 1.5e-5
maxiter 500
end
basis spherical
P library Def2-SV(P)
C library Def2-SV(P)
H library Def2-SV(P)
end
dft
grid fine
tolerances tight
convergence energy 1e-8
iterations 100
xc becke88 1.0 lyp 1.0
direct
end
task dft optimize
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