[gpaw-users] Generating a core-hole setup with generator2

[Eric Hermes]

Marcin,

On 3/20/2015 6:56 AM, Marcin Dulak wrote:
> Hi,
>
> On 03/19/2015 07:16 PM, Eric Hermes wrote:
>> Hello,
>>
>> I am attempting to generate a setup for Pd with a core hole in the 3d 
>> state using generator2. If I generate the setup with '-f PBE -w -s Pd 
>> --core-hole 3d,1.0', several new additional bound states appear that 
>> did not exist in the ground-state calculation (2 s-states, 2 
>> p-states, and 3 d-states). Here is an example output from this 
>> calculation:
>> https://gist.github.com/ehermes/6c85184e16d43acb6992
>>
>> If I instead generate the setup by specifying the electron 
>> configuration with '-C' (as [Ar] 3s2 3p6 3d9 4s2 4p6 4d10 5s1), I 
>> receive no error and get what appears to be a working core-hole setup 
>> for Pd. In addition, the total all-electron scalar-relativistic 
>> energy difference between the ground state and core-hole Pd atom is 
>> quite close to the experimental metallic Pd 3d binding energy (334.2 
>> eV vs ~335.2 eV). This indicates to me that this procedure works. 
>> However, I am not using the "--core-hole" argument to do this. Is 
>> what I am doing valid? Here's the output file from the calculation I 
>> have described:
>> https://gist.github.com/ehermes/3aec73bb427bbc6efe7c
>>
>> Also, I understand that the setups used for the ground state Pd and 
>> core-excited Pd should be of comparable quality, and that the best 
>> way to ensure this is to generate both setups as similarly as 
>> possible. However, the default setup parameters for Pd in generator2 
>> do not seem to produce a good quality setup. While the official 
>> setups produce lattice constants (3.946 for 10-electron and 3.937 for 
>> 18-electron) that are in fairly good agreement with an all-electron 
>> FP-LAPW calculation (3.948 angstrom), the default Pd setup generated 
>> by generator2 predicts a lattice constant that is more than 0.02 
>> angstrom too large (3.972). If I use the cutoffs from the official 
>> 10-electron setup ([2.3, 2.5, 2.2]) instead of generator2's default 
>> cutoff (2.4), the lattice constant is in much better agreement 
>> (3.958). As I am not an expert in generating pseudopotentials, I 
>> wonder what the best procedure here is, and how to best measure the 
>> quality of a setup. Any advice would be appreciated.
> i would not use the non-semicore datasets (that's how we call setups 
> now) like Pd 10-electron anymore.
> Most modern pseudopotentials (http://www.physics.rutgers.edu/gbrv/ 
> http://fpmd.ucdavis.edu/qso/potentials/index.htm 
> http://www.abinit.org/downloads/PAW2/OLD-VERSIONS/JTH-TABLE-0.1/index.html)
> dropped the idea of non-semicore ones because they are more difficult 
> to create.
> We don't have a working 10-electron Pd in generator2 (yet?). The 
> parameters for non-semicore datasets in generator2.py are just so 
> there is something there - they are not meant to be used.
> On the other hand we have an "optimized" version of 18-electron Pd:
> python -c "from gpaw.atom.generator2 import main as g; g(['Pd', '-f', 
> 'PBE', '-sw', '-P', '4s,5s,4p,5p,4d,0.5d,F', '-r', '1.98,2.5,2.05', 
> '-0', '5,1.69', '-pl', 'spdfg,-1.5:1.5:0.01'])"
> Try starting from the above.

Where do those parameters come from? I do not see them in generator2.py. 
How trustworthy are the default parameters in generator2.py? Where can I 
find the dataset parameters for the elements that have been "optimized"?

> Best regards,
>
> Marcin
>>
>> Thank you,
>> Eric Hermes
>>
>
>

-- 
Eric Hermes
J.R. Schmidt Group
Chemistry Department
University of Wisconsin - Madison