# Saddle point search with Gaussian

*From*: Krzysztof Radacki <krys.radacki -
at - ac.rwth-aachen.de>
*Organization*: Inst.Inorg.Chem., RWTH Aachen, Germany
*Subject*: Saddle point search with Gaussian
*Date*: Mon, 22 Jun 1998 14:44:07 +0000

`Dear CCL'ers,`

`I tried to find TS between two minima with Gaussian 94. All
standard ways like`

`OPT=TS or QST2 or QST3 failed. When I did 'manual'
search for changing one`

`angle which realy differs both structure - opening of 3-membered
ring (it means`

`OPT=Z-MATRIX and then in variables deklaration: a1=90.0 S 10 0.01)
I found value`

`for witch energii was the highest. FREQ calculations shows for
this structure`

`two negative frequencies. When I started for the same input
OPT=(saddle=2)`

`I became in log-file:`

`"Optimization stopped.`

` -- Wrong number of Negative eigenvalues: Desiered=
2 Actual= 0`

` -- Flag reset to prevent archiving."`
`So my question: `**What are this eigenvalues?** I've expected
after IR-calculation,

`that I should be near saddle point or minima. And second: `**Is
there any other**

`way to find TS or saddle point?`

`thanks in advance`

`
Krzys Radacki
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e-mail: Krys.Radacki - at -
ac.RWTH-Aachen.DE ---
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