Introduction: Pseudopotential families¶
As you might have seen in the previous
PWscf tutorial, the procedure of attaching a pseudopotential file to each atomic species could be a bit tedious. In many situations, you will not produce a different pseudopotential file for every calculation you do. More likely, when you start a project you will stick to a pseudopotential file for as long as possible. Moreover, in a high-throughput calculation, you will like to do calculation over several elements keeping the same functional. That’s also part of the reason why there are several projects (like PSLibrary or GBRV to name a few), that intend to develop a set of pseudopotentials that covers most of the periodic table for different functionals.
That’s why we added the pseudopotential families. Each family is a set of pseudopotentials that are grouped together in a special type of AiiDA Group of nodes. Within each family, at most one pseudopotential can be present for a given chemical element.
Of course, a pseudopotential family does not have to completely cover the periodic table (also because such pseudopotential sets do not exist). This means that you can create a pseudopotential family containing only the pseudopotentials for a few elements that you are interested in.
In principle, you can group different kinds of pseudopotentials into the same family. It is your responsibility to group only those with the same type, or obtained using the same functionals, approximations and / or levels of theory.
Creating a pseudopotential family¶
The following commands are specific to the Quantum ESPRESSO interface. For interfaces to other codes, please refer to the respective plugin documentation.
In the following, we will go through creating a pseudopotential family. First, you need to collect the pseudopotential files which should go into the family in a single folder – we’ll call it
path/to/folder. You can then add the family to the AiiDA database with
verdi data upf uploadfamily path/to/folder name_of_the_family "some description for your convenience"
name_of_the_family should be a unique name for the family, and the final parameter is a string that is set in the
description field of the group.
If the a pseudopotential family with the same
name_of_the_family exists already, the pseudopotentials in the folder will be added to the existing group. The code will raise an error if you try to add two (different) pseudopotentials for the same element.
After the upload (which may take some seconds, so please be patient) the upffamily will be ready to use.
If you upload pseudopotentials which are already present in your database, AiiDA will use the existing
UPFData node instead of creating a duplicate one. You can use the optional flag
--stop-if-existing to instead abort (without changing anything in the database) if an existing pseudopotential is found.
Getting the list of existing families¶
To see wich pseudopotential families already exist in the database, type
verdi data upf listfamilies
--with-description) flag if you also want to read the description of each family.
You can also filter the groups to get only a list of those containing a given set of elements using the
-e option. For instance, if you want to get only the families containing the elements
verdi data upf listfamilies -e Ba Ti O
For more help on the command line options, type
verdi data upf listfamilies -h
Manually adding pseudopotentials¶
If you do not want to use pseudopotentials from a family, it is also possible to manually add them to the database (even though we discourage this in general).
A possible way of doing it is the following: we start by creating a list of pseudopotential filenames that we need to use:
raw_pseudos = [ "Ba.pbesol-spn-rrkjus_psl.0.2.3-tot-pslib030.UPF", "Ti.pbesol-spn-rrkjus_psl.0.2.3-tot-pslib030.UPF", "O.pbesol-n-rrkjus_psl.0.1-tested-pslib030.UPF"]
In this simple example, we expect the pseudopotentials to be in the same folder of the script. Then, we loop over the filenames and add them to the AiiDA database. The
get_or_create method checks if the pseudopotential is already in the database and either stores it, or just returns the node already present in the database. The second value returned is a boolean and tells us if the pseudopotential was already present or not. We also store the returned nodes in a list (
UpfData = DataFactory('upf') pseudos_to_use =  for filename in raw_pseudos: absname = os.path.abspath(filename) pseudo, created = UpfData.get_or_create(absname,use_first=True) pseudos_to_use.append(pseudo)
As the last step, we make a loop over the pseudopotentials, and attach its pseudopotential object to the calculation:
for pseudo in pseudos_to_use: calc.use_pseudo(pseudo, kind=pseudo.element)
When the pseudopotential is created, it is parsed and the elements to which it refers is stored in the database and can be accessed using the
pseudo.element property, as shown above.