The PSML format and library for norm-conserving pseudopotential data curation and interoperability

TL;DR

This paper introduces the PSML format and libPSML library to standardize and facilitate interoperability of norm-conserving pseudopotential data across electronic-structure software, improving reproducibility and comparison of results.

Contribution

The paper presents a new flexible file format and software library that enable seamless data exchange and provenance tracking for norm-conserving pseudopotentials in electronic structure calculations.

Findings

Support implemented in several pseudopotential generators

Linked with Siesta and Abinit for consistent pseudopotential use

Facilitates comparison of structural and electronic properties

Abstract

Norm-conserving pseudopotentials are used by a significant number of electronic-structure packages, but the practical differences among codes in the handling of the associated data hinder their interoperability and make it difficult to compare their results. At the same time, existing formats lack provenance data, which makes it difficult to track and document computational workflows. To address these problems, we first propose a file format (PSML) that maps the basic concepts of the norm-conserving pseudopotential domain in a flexible form and supports the inclusion of provenance information and other important metadata. Second, we provide a software library (libPSML) that can be used by electronic structure codes to transparently extract the information in the file and adapt it to their own data structures, or to create converters for other formats. Support for the new file format has been already implemented in several pseudopotential generator programs (including ATOM and ONCVPSP), and the library has been linked with Siesta and Abinit, allowing them to work with the same pseudopotential operator (with the same local part and fully non-local projectors) thus easing the comparison of their results for the structural and electronic properties, as shown for several example systems. This methodology can be easily transferred to any other package that uses norm-conserving pseudopotentials, and offers a proof-of-concept for a general approach to interoperability.