Numerical and Analytical Hessian routines give vastly different answers about nwchem HOT 3 CLOSED

@jbecca You need xfine grid in the hessian input section and you need to be very strict in the geometry optimization. Have a look at the attached input and output files
fufu.nw.txt
fufu.output.txt

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@edoapra Is the xfine grid something that should always be set for calculating the analytical frequencies? I would have normally assumed that any grid or numerical instability would have shown up first in the finite difference hessian method.

Thanks for the help on this.

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@jbecca No, the analytical frequencies are more likely to be affected by numerical issue, both in first determining the minimum and then in evaluating the hessian

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