Dirac-Fock-Breit self-consistent-field method: Gaussian basis-set calculations on many-electron atoms

Matrix Dirac–Fock–Coulomb and Dirac–Fock–Breit self-consistent field calculations are performed for a number of neutral atoms. He (Z = 2) through Xe (Z = 54), using the universal Gaussian basis set (18s, 12p, 11d) reported recently by Da Silva etal. The total Dirac–Fock–Coulomb, the Dirac–Fock–Breit, and the Breit interaction energies calculated with this universal Gaussian basis set are in good agreement with the corresponding values obtained by using an extensive well-tempered Gaussian basis set for the He through Ca (Z = 20) atoms. Although this universal Gaussian basis set is inadequate for the calculation of total Dirac–Fock–Coulomb and Dirac–Fock–Breit energies for the Kr, Sr, and Xe atoms, the Breit interaction energies calculated with this basis for these three atoms are in very good agreement with the corresponding Breit interaction energies obtained by using the extensive well-tempered Gaussian basis sets. Work is in progress to generate a more extensive and energetically better universal Gaussian basis set for He through Xe for its use in non-relativistic Hartree–Fock as well as Dirac–Fock self-consistent field calculations on polyatomics involving heavy atoms.

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Spin State Ordering in Metal-Based Compounds Using the Localized Active Space Self-Consistent Field Method

10.26434/chemrxiv.8965973 ◽

2019 ◽

Author(s):

Riddhish Pandharkar ◽

Matthew R. Hermes ◽

Christopher J. Cramer ◽

Laura Gagliardi

Keyword(s):

Spin State ◽

Computational Cost ◽

Field Method ◽

Basis Set ◽

Strongly Correlated ◽

Active Space ◽

Embedding Theory ◽

Consistent Field ◽

Self Consistent ◽

Self Consistent Field

Quantitatively accurate calculations for spin state ordering in transition-metal complexes typically demand a robust multiconfigurational treatment. The poor scaling of such methods with increasing size makes them impractical for large, strongly correlated systems. Density matrix embedding theory (DMET) is a fragmentation approach that can be used to specifically address this challenge. The single-determinantal bath framework of DMET is applicable in many situations, but it has been shown to perform poorly for molecules characterized by strong correlation when a multiconfigurational self-consistent field solver is used. To ameliorate this problem, the localized active space self-consistent field (LASSCF) method was recently described. In this work, LASSCF is applied to predict spin state energetics in mono- and di-iron systems and we show that the model offers an accuracy equivalent to CASSCF but at a substantially lower computational cost. Performance as a function of basis set and active space is also examined.

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Spin State Ordering in Metal-Based Compounds Using the Localized Active Space Self-Consistent Field Method

10.26434/chemrxiv.8965973.v1 ◽

2019 ◽

Author(s):

Riddhish Pandharkar ◽

Matthew R. Hermes ◽

Christopher J. Cramer ◽

Laura Gagliardi

Keyword(s):

Spin State ◽

Computational Cost ◽

Field Method ◽

Basis Set ◽

Strongly Correlated ◽

Active Space ◽

Embedding Theory ◽

Consistent Field ◽

Self Consistent ◽

Self Consistent Field

Quantitatively accurate calculations for spin state ordering in transition-metal complexes typically demand a robust multiconfigurational treatment. The poor scaling of such methods with increasing size makes them impractical for large, strongly correlated systems. Density matrix embedding theory (DMET) is a fragmentation approach that can be used to specifically address this challenge. The single-determinantal bath framework of DMET is applicable in many situations, but it has been shown to perform poorly for molecules characterized by strong correlation when a multiconfigurational self-consistent field solver is used. To ameliorate this problem, the localized active space self-consistent field (LASSCF) method was recently described. In this work, LASSCF is applied to predict spin state energetics in mono- and di-iron systems and we show that the model offers an accuracy equivalent to CASSCF but at a substantially lower computational cost. Performance as a function of basis set and active space is also examined.

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Basis set superposition error free self-consistent field method for molecular interaction in multi-component systems: Projection operator formalism

The Journal of Chemical Physics ◽

10.1063/1.1388039 ◽

2001 ◽

Vol 115 (8) ◽

pp. 3553-3560 ◽

Cited By ~ 58

Author(s):

Takeshi Nagata ◽

Osamu Takahashi ◽

Ko Saito ◽

Suehiro Iwata

Keyword(s):

Projection Operator ◽

Molecular Interaction ◽

Field Method ◽

Basis Set ◽

Operator Formalism ◽

Basis Set Superposition Error ◽

Consistent Field ◽

Component Systems ◽

Self Consistent ◽

Self Consistent Field

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A First Principles Approach for Partitioning Linear Response Properties into Additive and Cooperative Contributions

10.26434/chemrxiv.5773968.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Daniel Lambrecht ◽

Eric Berquist

Keyword(s):

First Principles ◽

Linear Response ◽

Building Blocks ◽

Field Method ◽

Response Property ◽

Response Properties ◽

Consistent Field ◽

Molecular Building Blocks ◽

Self Consistent ◽

Self Consistent Field

We present a first principles approach for decomposing molecular linear response properties into orthogonal (additive) plus non-orthogonal/cooperative contributions. This approach enables one to 1) identify the contributions of molecular building blocks like functional groups or monomer units to a given response property and 2) quantify cooperativity between these contributions. In analogy to the self consistent field method for molecular interactions, SCF(MI), we term our approach LR(MI). The theory, implementation and pilot data are described in detail in the manuscript and supporting information.

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