Author Topic: keeptmode  (Read 5460 times)

chburger

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keeptmode
« on: July 07, 2007, 06:10:26 pm »
I would like to learn about the exact meaning of  "keeptmode"
of statpt.

- I know that it will freeze the transition vector index - this means
exactly what? Let' assume that I want to use the 2nd mode as the
transition vector in a TS optimization.
Will the second mode will be kept as the transition vector
when the first imaginary mode is becoming a real mode
during the statpt optimization when using keetmode 1?
 

turbomaster

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Re: keeptmode
« Reply #1 on: July 09, 2007, 10:15:01 am »
The keyword "keeptmode" means that the index of transition vector will not change. This means that if you specify 2nd mode and "keeptmode" you will in fact not locate the transition structure because you will always maximize along the second vector. The Hessian eigenvectors are always sorted from the lowest to the highest, so at the true transition state the second mode must be positive. This keyword should be used only if you specify the 1st mode and you encounter mode flipping, i.e. the mode oscillates during the optimization.