TY - JOUR
T1 - Zero-Field Splitting Parameters from Four-Component Relativistic Methods
AU - Reynolds, Ryan D.
AU - Shiozaki, Toru
N1 - Funding Information:
The authors thank Scott Coste and Danna Freedman for helpful discussions. R.D.R. has been supported by the DOD National Defense Science and Engineering Graduate (NDSEG) Fellowship, 32 CFR 168a. T.S. has been supported by the NSF CAREER Award (CHE-1351598). T.S. is an Alfred P. Sloan Research Fellow. Some of the computations were performed with the aid of the ERDC DSRC high-performance computing resources (AFOSR40403702).
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/3/12
Y1 - 2019/3/12
N2 - 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.
AB - 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.
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U2 - 10.1021/acs.jctc.8b00910
DO - 10.1021/acs.jctc.8b00910
M3 - Article
C2 - 30689942
AN - SCOPUS:85062397478
VL - 15
SP - 1560
EP - 1571
JO - Journal of Chemical Theory and Computation
JF - Journal of Chemical Theory and Computation
SN - 1549-9618
IS - 3
ER -