[QE-users] problem with QE NEB calculations

[Giuseppe Mattioli]

Dear User (please sign always all your posts to this forum with name  
and scientific affiliation)

The detection of a potential energy barrier along a given reaction  
coordinate may depend on how you assign the initial and final state,  
on your tight or loose convergence criterion on forces, on the number  
of images you use to map the reaction coordinate. For example, if your  
initial state is a very shallow local energy minimum (or a saddle  
point), you might observe no barrier at all between initial and final  
state. It is impossible to say more than this without carefully  
looking at the system you are simulating.
HTH
Giuseppe

Quoting sahar mohammadi <saharmohammadi683 at gmail.com>:

> Dear QE users and developers
>
> I have simulated a reaction of carbon monoxide oxidation on a metal oxide
> cluster. Based on relax calculations the total energy value decreases after
> each iteration until reaches the final value at the last iteration.
> However, most of oxidation reactions have energy barrier (activation
> energy) in reaction energy path. So, NEB calculations also give a just
> decreasing energy path for reaction path. I would be thankful if anyone
> could help or have the same experience with QE to simulate energy barrier
> in the reaction path.



GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <giuseppe.mattioli at ism.cnr.it>