[Pw_forum] pwscf question- R-halide comparison

[Tony Phuc Hoang]

I am trying to compare R-Br and R-Cl systems.

For the chlorine, I've used Cl.pbe-n-van.UPF and for the bromine 
Br.pbe-van_mit.UPF

I know that bromine reacts faster than chlorine, so it should have a 
lower barrier. But when I compared the neb using the above 
pseudopotentials, the bromine has a higher barrier. The atoms in the 
R-groups all use ultrasoft.

My question is, is it because the pseudopotentials of the bromine and 
chlorine different that is causing the mix up (sort of like comparing 
apples to oranges)? Do you have any recommendations? Thanks.