[CPMD-list] Re: Fermi Energy of Bulk Gold

[Zhenyu LI]

Dear Ari, Eyvaz, and Abraham

Thanks for your suggestions.
 
>    I guess that you took the value for chemical potential directly from the
> output from the bulk calculation for gold, right? That value is arbitrary,
> since it hasn't been adjusted with respect to the vacuum level, what is
> probably the case with the value of 5.3 eV.

How to get the vacuum level then?  For surface system, it seems that I can 
use ELECTROSTATIC POTENTIAL keyword, and find the electrostatic potential
value at vacuum position. right? But I don't know how to do it for bulk system.
 
>    Another point: I strongly suggest you to use Fermi broadening (keyword
> 'FREE ENERGY FUNCTIONAL') for this calculation! It might be that the
> calculation converges, however the probability that you're trapped in a
> local minimum is high. 

The default electron temperature for FREE ENERGY FUNCTIONAL is high.
If I want to calculate the electronic structure for zero temperature,  how about
to directly set TEMPERATURE ELECTRON to zero with FREE ENERGY FUNCTIONAL? 

>And should you experience problems with convergence,
> you should employ some mixing of the electron density.

I have expected that if I don't specify any mixing keywords in my
input file, a default
mixing scheme ( Anderson ? )  will be used, right? 

And if anybody can share some experience on choosing mixing method, it
will be  greatly
appreciated. There are a few mixing methods in CPMD, but I don't know
which one should
be chosen for a specific problem. 

Best wishes,
Zhenyu