[CPMD-list] equilibrated system?

[Nico Zobel]

Dear Axel,

thank you for taking the time to look at my problem.

> furthermore, i have serious doubts, that you will get a good
> representation of the chemistry of your system with the  
> pseudopotentials
> for magnesium and lithium that you use (where did you get them, btw?
> were there any recommendations on where to apply them?).
> both potentials look as if they were designed for the metals,
> but not for oxides. if you look at the electron density of your
> MgO slab, you'll see that almost all electron density of the Mg
> atoms has been 'stripped off'. the same goes for the Li potential.
> i would expect, that you need semi-core potentials in both cases.
>

Since I could not find PBE-USPPs for neither Mg nor Li in any of the  
common
pseudopotential libraries I generated them myself with Vanderbilt's  
code.

Does "semi-core potentials" mean that the number of electrons that  
are to
be treated as valence electrons should be larger?


> one more stupid question: is it intentional, that your methane
> is closer to the bottom of your slab than your top?
>

I'm interested in the hydrogen abstraction from methane. The  
configuration
you have seen is the educt configuration. The product configuration
will be a methyl radical and a hydrogen atom adsorbed at the surface.  
In this
configuration the methyl radical is situated approximately halfway  
between the
adsorbed hydrogen atom and the bottom of the MgO-slab.


Best regards,

Nico.