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Relativistic exact two-component theory in the generalized pseudospectral representation

Xubo Wang1, Phay J. Ho2,*, Chaoqun Zhang3, and Lan Cheng1,†

  • *Contact author: pho@anl.gov
  • †Contact author: lcheng24@jhu.edu
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Phys. Rev. A 113, 042802 – Published 2 April, 2026

DOI: https://doi.org/10.1103/mpyz-tvqs

Abstract

We present a formulation and implementation of exact two-component (X2C) relativistic theory in the generalized pseudospectral representation. When combined with the Hartree-Fock-Slater framework, this approach enables efficient and accurate treatments of scalar-relativistic and spin-orbit effects in atomic electronic structures without the computational overhead of four-component methods. Benchmark calculations across light and heavy elements demonstrate that the our X2C scheme yields substantially more accurate relativistic corrections to core-electron binding energies than perturbational Breit-Pauli treatments while converging more rapidly with respect to basis size. The method provides an improved computational framework for modeling ultrafast x-ray-induced processes in heavy-element systems.

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Phys. Rev. A 113, 042802– Published 2 April, 2026
  • Received 31 October 2025
  • Accepted 11 March 2026
Article part of CHORUS
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