Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly

Re^2: optimization process and transition state

B. Koa

Dear Alex Granovsky

Many Thanks for your kind attentions and helpful comments.

Truly Yours
B. Koa

On Sun Sep 26 '10 10:26am, Alex Granovsky wrote
>Dear B. Koa,

>this can be the indication that there is no transition state.
>However, please take in mind that the default geometry optimization
>code in Firefly try to avoid saddle points and their vicinities
>by its design; and in most cases it is quite successful in doing this.

>Thus, the saddle point can be still there but just was walked
>around during geometry optimization. In most cases it is very
>helpful to look at the graph of energy vs. optimization step;
>e.g., using ChemCraft. Look at the flat regions somewhere at the
>middle of the optimization process (if any), they can be close to
>TS structures.
>Finally, my guess is that for the process you are modeling,
>the existence or absence of TS should depend on the level of
>theory used in computations.

>Alex Granovsky
>On Mon Sep 20 '10 2:42pm, B. Koa wrote
>>Dear Firefly Users

>>When I optimized a "H2O2" molecule on a cluster surface, it dissociated to 2 "OH"s which adsorbed on the cluster through the optimization process. Through this optimization process by Firefly the scf energies decrease and finally the job completes. Now, Can I be sure that there is not any transition state for H2O2 dissociation here ? I appreciate your help in advance.

>>Best Wishes
>>B. Koa  

[ Previous ] [ Next ] [ Index ]           Tue Sep 28 '10 9:39pm
[ Reply ] [ Edit ] [ Delete ]           This message read 745 times