Electron spin-spin coupling from multireference configuration interaction wave functions

Gilka, Natalie; Taylor, Peter R.; Marian, Christel M.

doi:10.1063/1.2948402

Cited by 31 publications

(23 citation statements)

References 50 publications

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“…For an extension of the formalism to spin-dependent Hamiltonians. 28,30 To maintain a consistent energy splitting between the CSFs, a scaling factor of (1 − p X ) was introduced in the redesigned Hamiltonians. 33 ωwjĤ…”

Section: Off-diagonal Matrix Elements Among Csfs Of the Same Configmentioning

confidence: 99%

“…8,[24][25][26] The original DFT/MRCI method 17 was devised for electronic singlet and triplet states as these are the most common spin multiplicities encountered in organic molecules. Further technical developments included the extension of the method to spindependent Hamiltonians [27][28][29][30] and the parallelization of the code, 31 thus significantly widening its application range. Benchmarks of electronic excitation energies of small-to medium-sized organic molecules against CASPT2 results 32 showed the superiority of the DFT/MRCI method compared to TDDFT in conjunction with typical density functionals.…”

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confidence: 99%

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The DFT/MRCI method

Marian

Heil

Kleinschmidt

2018

WIREs Comput Mol Sci

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147

154

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In the past two decades, the combined density functional theory and multireference configuration interaction (DFT/MRCI) method has developed from a powerful approach for computing spectral properties of singlet and triplet excited states of large molecules into a more general multireference method applicable to states of all spin multiplicities. In its original formulation, it shows great efficiency in the evaluation of singlet and triplet excited states which mainly originate from local one-electron transitions. Moreover, DFT/MRCI is one of the few methods applicable to large systems that yields the correct ordering of states in extended π-systems where double excitations play a significant role. A recently redesigned DFT/MRCI Hamiltonian extends the application range of the method to bichromophores such as hydrogen-bonded or π-stacked dimers and loosely coupled donor-acceptor systems. In conjunction with a restricted-open shell Kohn-Sham optimization of the molecular orbitals, even electronically excited doublet and quartet states can be addressed. After a short outline of the general ideas behind this semi-empirical method and a brief review of alternative approaches combining density functional and multireference wavefunction theory, formulae for the DFT/MRCI Hamiltonian matrix elements are presented and the adjustments of the two-electron contributions are discussed. The performance of the DFT/MRCI variants on excitation energies of organic molecules and transition metal compounds against experimental or ab initio reference data is analyzed and case studies are presented which show the strengths and limitations of the method. Finally, an overview over the properties available from DFT/MRCI wavefunctions and further developments is given.ABBREVIATIONS: ACRXTN, 3-(9,9-dimethylacridin-10[9H]-yl)-9H-xanthen-9-one; AO, atomic orbital; CASSCF, Complete active space self-consistent field; CASPT2, Complete active space second-order perturbation theory; CCSD(T), Coupled-cluster with singles and doubles and perturbative treatment of triples; CC2, Coupled-cluster with approximate treatment of doubles; CD, Circular dichroism; CI, Configuration interaction; CIPSI, configuration interaction by perturbation with multiconfigurational zeroth-order wave functions selected by iterative

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Section: Off-diagonal Matrix Elements Among Csfs Of the Same Configmentioning

confidence: 99%

mentioning

confidence: 99%

The DFT/MRCI method

Marian

Heil

Kleinschmidt

2018

WIREs Comput Mol Sci

Self Cite

147

154

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“…To avoid the slow evaluation of matrix elements over configuration state functions (CSFs) determinant by determinant, various procedures have been proposed. The SOC kit ( Spock ), developed in our laboratory some time ago,87,83 employs an extension of the pattern approach of Wetmore and Segal92,93 to spin‐dependent operators 94,95. The same general idea is pursued in the table configuration interaction96 and the symbolic matrix element methods97 and the corresponding generalizations to spin‐dependent operators 98, 99.…”

Section: Spin–orbit Couplingmentioning

confidence: 99%

Spin–orbit coupling and intersystem crossing in molecules

Marian

2011

WIREs Comput Mol Sci

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723

799

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Many light‐induced molecular processes involve a change in spin state and are formally forbidden in non‐relativistic quantum theory. To make them happen, spin–orbit coupling (SOC) has to be invoked. Intersystem crossing (ISC), the nonradiative transition between two electronic states of different multiplicity, plays a key role in photochemistry and photophysics with a broad range of applications including molecular photonics, biological photosensors, photodynamic therapy, and materials science. Quantum chemistry has become a valuable tool for gaining detailed insight into the mechanisms of ISC. After a short introduction highlighting the importance of ISC and a brief description of the relativistic origins of SOC, this article focusses on approximate SOC operators for practical use in molecular applications and reviews state‐of‐the‐art theoretical methods for evaluating ISC rates. Finally, a few sample applications are discussed that underline the necessity of studying the mechanisms of ISC processes beyond qualitative rules such as the El‐Sayed rules and the energy gap law. © 2011 John Wiley & Sons, Ltd. This article is categorized under: Structure and Mechanism > Molecular Structures

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“…[33][34][35][36][37][38] A similar treatment of SOC was implemented in the MOLCAS code 39 based on the restricted active space state interaction spin-orbit (RASSI-SO) scheme, 40,41 which was used to study ZFS phenomena in transition metal complexes. [42][43][44][45][46][47][48][49] Finally, we mention the work of Gilka et al on SSC 50 and the ZFS calculations on organic molecules by Sugisaki and co-workers. 51 The binuclear copper(II) acetate complex described by Bleaney and Bowers 52 is one of the first examples of a polynuclear system with anisotropic interactions and has been the subject of several studies.…”

Section: Introductionmentioning

confidence: 97%

Antisymmetric Magnetic Interactions in Oxo-Bridged Copper(II) Bimetallic Systems

Maurice

Pradipto

Guihéry

et al. 2010

J. Chem. Theory Comput.

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The antisymmetric magnetic interaction is studied using correlated wave-function-based calculations in oxo-bridged copper bimetallic complexes. All of the anisotropic multispin Hamiltonian parameters are extracted using spin-orbit state interaction and effective Hamiltonian theory. It is shown that the methodology is accurate enough to calculate the antisymmetric terms, while the small symmetric anisotropic interactions require more sophisticated calculations. The origin of the antisymmetric anisotropy is analyzed, and the effect of geometrical deformations is addressed.

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Electron spin-spin coupling from multireference configuration interaction wave functions

Cited by 31 publications

References 50 publications

The DFT/MRCI method

The DFT/MRCI method

Spin–orbit coupling and intersystem crossing in molecules

Antisymmetric Magnetic Interactions in Oxo-Bridged Copper(II) Bimetallic Systems

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