about the dimer and CI-NEB method

[hlzya]

Hi,

I have two questions.

1. How can I prove the found TS using the dimer and NEB methods is the one connecting with my initial state and final state (use imaginary vibration mode?).

2. If there are two TSs between the initial state and the final state, how to find them using the dimer method (from one assumption, I only can find one TS).

Thanks.

Yi-An

[graeme]

Once you have a saddle point you can displace the configuration by a small amount along the negative mode direction (both ways) and minimize to find the connecting minima. Using a conservative minimizer such as with damped dynamics will help to make sure that you don't skip over any local minima.

If you have an initial and final state, and want to find the saddles along a minimum energy path between them, the NEB is a good approach. You can always refine any saddles that you find with the dimer. It could be slow-going, however, to use the dimer method to find searches along a particular pathway that you care about. Of course, you can always try to interpolate between your initial and final states to initiate saddle point searches; this might work for some cases, but I don't think it will be better than using the NEB which is designed to give you a minimum energy path between the initial and final states.

[hlzya]

Thanks a lot.

Yi-An