dft geopt problem

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8:21:48 AM PDT - Tue, Apr 10th 2012

I'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