Zero-Field Splitting Parameters from Four-Component Relativistic Methods

Ryan D. Reynolds*, Toru Shiozaki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We report an approach for determination of zero-field splitting parameters from four-component relativistic calculations. Our approach involves neither perturbative treatment of spin-orbit interaction nor truncation of the spin-orbit coupled states. We make use of a multi-state implementation of relativistic complete active space perturbation theory (CASPT2), partially contracted N-electron valence perturbation theory (NEVPT2), and multi-reference configuration interaction theory (MRCI), all with the fully internally contracted ansatz. A mapping is performed from the Dirac Hamiltonian to the pseudospin Hamiltonian, using correlated energies and the magnetic moment matrix elements of the reference wave functions. Direct spin-spin coupling is naturally included through the full 2-electron Breit interaction. Benchmark calculations on chalcogen diatomics and pseudotetrahedral cobalt(II) complexes show accuracy comparable to the commonly used state-interaction with spin-orbit (SI-SO) approach, while tests on a uranium(III) single-ion magnet suggest that for actinide complexes the strengths of our approach through the more robust treatment of spin-orbit effects and the avoidance of state truncation are of greater importance.

Original languageEnglish (US)
Pages (from-to)1560-1571
Number of pages12
JournalJournal of Chemical Theory and Computation
Issue number3
StatePublished - Mar 12 2019

ASJC Scopus subject areas

  • Computer Science Applications
  • Physical and Theoretical Chemistry


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