Trying to understand details of pseudopotential input files for atoms

[kira_selby]

Hello,

I am a more computer science-oriented person (with some cursory knowledge of chemistry/quantum physics from a physics undergrad, but only cursory) who is working with some stuff related to Vasp for a project related to machine learning. Right now I am trying to understand the pseudopotential files that are used to make the POTCAR files. My understanding is that these files are used to represent the states of individual atoms in vasp, and it would be helpful to understand a little more about how this representation works for a project I am working on. I have found various documentation on the pseudopotential method and projector augmented wave method (such as papers like this or this ), but I am having trouble finding documentation on how that is implemented in VASP and what the data in the pseudopotential files themselves correspond to. When I open them up I see a lot of blocks of the form
[title]
# # # # #
# # # # #
....

But I am having trouble parsing these. Are these matrix operators of some form? Or just scalar valued quantities evaluated on some sort of radial grid? If so, is the grid specified anywhere? Some of these blocks also seem to have different numbers of entries from each other, and there are some titles that seem to be repeated.

Is there any comprehensive documentation on how to parse what this means or how VASP uses it anywhere?

[support_vasp]

Hi,

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VASP