Subject: TS imaginary freq. value

From: val <[email-masked]>
Date: Mon, 22 Feb 1999 20:01:07 +0300

Dear CCL'ers,

I have got a Transition State (TS) structure with unusually low 
imaginary frequency value, about 17 CM**-1.
However, the gradient convergence criterion is satisfied, Hessian
is correct (only one imaginary freq.), visualization of the normal
mode gives right picture and Intrinsic Reaction Coordinate 
optimization connects the TS to reactants and products.

Is this enough to proof that the saddle point is true TS of the 
reaction of interest?

Does it make any sense to take into account the value of the 
imaginary frequency? In what range should it be for the most
common cases?

Any references on TS imaginary frequency value interpretation
are really welcome.

Thanks in advance, I will summarize as usual.

sincerely yours,
Valentin.

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