On the definition of local spin in relativistic and nonrelativistic quantum chemistry

Reiher, Markus

doi:10.1039/b605229k

Cited by 71 publications

(79 citation statements)

References 98 publications

(121 reference statements)

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“…[15,[37][38][39] To make things even worse, the treatment of low-spin states usually requires the use of a broken-symmetry description, [40][41][42][43] which provides an unphysical spin density by construction (see, e.g., Refs. [24,44] for a discussion). This precludes the simple prediction of spectroscopic properties depending on the spin density (for schemes to address this difficulty, see e.g., Refs.…”

Section: Introductionmentioning

confidence: 99%

Spin in density‐functional theory

Jacob¹,

Reiher²

2012

Int J of Quantum Chemistry

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The accurate description of open-shell molecules, in particular of transition metal complexes and clusters, is still an important challenge for quantum chemistry. Although density-functional theory (DFT) is widely applied in this area, the sometimes severe limitations of its currently available approximate realizations often preclude its application as a predictive theory. Here, we review the foundations of DFT applied to open-shell systems, both within the nonrelativistic and the relativistic framework. In particular, we provide an in-depth discussion of the exact theory, with a focus on the role of the spin density and possibilities for targeting specific spin states. It turns out that different options exist for setting up Kohn-Sham DFT schemes for open-shell systems, which imply different definitions of the exchangecorrelation energy functional and lead to different exact conditions on this functional. Finally, we suggest possible directions for future developments.

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Section: Introductionmentioning

confidence: 99%

Spin in density‐functional theory

Jacob¹,

Reiher²

2012

Int J of Quantum Chemistry

Self Cite

220

224

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“…Contact densities are most sensitive to the proper set-up of transformation of operators [93,94,[98][99][100]. Picture change affected results are dramatically wrong.…”

Section: Contact Densitiesmentioning

confidence: 99%

Exact decoupling of the relativistic Fock operator

2012

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It is generally acknowledged that the inclusion of relativistic effects is crucial for the theoretical description of heavy-element-containing molecules. Four-component Dirac-operator-based methods serve as the relativistic reference for molecules and highly accurate results can be obtained-provided that a suitable approximation for the electronic wave function is employed. However, four-component methods applied in a straightforward manner suffer from high computational cost and the presence of pathologic negative-energy solutions. To remove these drawbacks, a relativistic electron-only theory is desirable for which the relativistic Fock operator needs to be exactly decoupled. Recent developments in the field of relativistic two-component methods demonstrated that exact decoupling can be achieved following different strategies. The theoretical formalism of these exact-decoupling approaches is reviewed in this paper followed by a comparison of efficiency and results.Keywords Relativistic electronic structure theory Á Fock operator Á Douglas-Kroll-Hess method Á X2C method Á Picture change error 1 Introduction

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“…26 The self-interaction error inherent in the method leads to somewhat too delocalised systems, but the use of Hartree-Fock exchange in the functional mostly overcomes the problem.…”

Section: 25mentioning

confidence: 99%