PSML is a file format for norm-conserving pseudopotential data which is designed to encapsulate as much as possible the concepts in the domain’s ontology. For example, the format, together with its supporting processing library, offers a very good approximation to an abstract mathematical function (an object which produces a value from its input). PSML also provides a rich set of metadata to document the provenance (i.e., the generation history) and the generation conditions and flavor of the pseudopotential. The format is based on XML, and it is by nature extensible, offering a basic set of elements and a number of extra features that can be exploited for sophisticated uses or future improvements.
As first steps in the implementation of the PSML vision, we have modified two different atomic pseudopotential generation codes to generate PSML files, and interfaced libPSML to two electronic-structure programs.
Example PSML files can be found in the examples directory of the
libPSML distribution, and also in the databases of
pseudopotentials that support the format.