# CCL: Freq and Stability

*From*: "Anthony F" <kwyjib09~!~gmail.com>
*Subject*: CCL: Freq and Stability
*Date*: Fri, 14 May 2010 13:34:01 -0400

Sent to CCL by: "Anthony F" [kwyjib09*_*gmail.com]
Dear CCL,
I've been running geometry optimizations and found stationary points. I have
also been using SCF = QC (also UB3LYP/6-311+G(d,p) NOSYMM).
How can I be sure that my final answer is a local minimum? When I perform a
frequency job after the optimization, I sometimes obtain imaginary frequencies,
suggesting an nth-order saddle point (n is the number of imaginary frequencies).
Does this also have to do with the stability of my wavefunction? I have used the
keyword Stable=Opt for verification. But I find that I can have both a stable
wavefunction and imaginary frequencies. How do I then find true local minima?
Also, is it possible to run both a STABLE and geometry OPT job with the same
route? Or do I have to use the Link1 keyword? If so, is it possible to copy my
checkpoint file through the route section?
Thanks
Anthony