Ab initio density matrix renormalization group study of magnetic coupling in dinuclear iron and chromium complexes
Abstract
The applicability of ab initio multireference wavefunctionbased methods to the study of magnetic complexes has been restricted by the quickly rising activespace requirements of oligonuclear systems and dinuclear complexes with S > 1 spin centers. Ab initio density matrix renormalization group (DMRG) methods built upon an efficient parameterization of the correlation network enable the use of much larger active spaces, and therefore may offer a way forward. Here, we apply DMRGCASSCF to the dinuclear complexes [Fe{sub 2}OCl{sub 6}]{sup 2−} and [Cr{sub 2}O(NH{sub 3}){sub 10}]{sup 4+}. After developing the methodology through systematic basis set and DMRG M testing, we explore the effects of extended active spaces that are beyond the limit of conventional methods. We find that DMRGCASSCF with active spaces including the metal d orbitals, occupied bridgingligand orbitals, and their virtual double shells already capture a major portion of the dynamic correlation effects, accurately reproducing the experimental magnetic coupling constant (J) of [Fe{sub 2}OCl{sub 6}]{sup 2−} with (16e,26o), and considerably improving the smaller active space results for [Cr{sub 2}O(NH{sub 3}){sub 10}]{sup 4+} with (12e,32o). For comparison, we perform conventional MRCI+Q calculations and find the J values to be consistent with those from DMRGCASSCF. In contrast to previous studies, the highermore »
 Authors:
 Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 6068103 (Japan)
 Institute for Molecular Science, 38 NishigoNaka, Myodaiji, Okazaki 4448585 (Japan)
 Publication Date:
 OSTI Identifier:
 22255172
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AMMONIA; CHROMIUM COMPLEXES; COUPLING CONSTANTS; DENSITY MATRIX; HIGH SPIN STATES; IRON; LIGANDS; RENORMALIZATION; SPECTRA; WAVE FUNCTIONS
Citation Formats
Harris, Travis V., Morokuma, Keiji, Email: morokuma@fukui.kyotou.ac.jp, Kurashige, Yuki, and Yanai, Takeshi. Ab initio density matrix renormalization group study of magnetic coupling in dinuclear iron and chromium complexes. United States: N. p., 2014.
Web. doi:10.1063/1.4863345.
Harris, Travis V., Morokuma, Keiji, Email: morokuma@fukui.kyotou.ac.jp, Kurashige, Yuki, & Yanai, Takeshi. Ab initio density matrix renormalization group study of magnetic coupling in dinuclear iron and chromium complexes. United States. doi:10.1063/1.4863345.
Harris, Travis V., Morokuma, Keiji, Email: morokuma@fukui.kyotou.ac.jp, Kurashige, Yuki, and Yanai, Takeshi. 2014.
"Ab initio density matrix renormalization group study of magnetic coupling in dinuclear iron and chromium complexes". United States.
doi:10.1063/1.4863345.
@article{osti_22255172,
title = {Ab initio density matrix renormalization group study of magnetic coupling in dinuclear iron and chromium complexes},
author = {Harris, Travis V. and Morokuma, Keiji, Email: morokuma@fukui.kyotou.ac.jp and Kurashige, Yuki and Yanai, Takeshi},
abstractNote = {The applicability of ab initio multireference wavefunctionbased methods to the study of magnetic complexes has been restricted by the quickly rising activespace requirements of oligonuclear systems and dinuclear complexes with S > 1 spin centers. Ab initio density matrix renormalization group (DMRG) methods built upon an efficient parameterization of the correlation network enable the use of much larger active spaces, and therefore may offer a way forward. Here, we apply DMRGCASSCF to the dinuclear complexes [Fe{sub 2}OCl{sub 6}]{sup 2−} and [Cr{sub 2}O(NH{sub 3}){sub 10}]{sup 4+}. After developing the methodology through systematic basis set and DMRG M testing, we explore the effects of extended active spaces that are beyond the limit of conventional methods. We find that DMRGCASSCF with active spaces including the metal d orbitals, occupied bridgingligand orbitals, and their virtual double shells already capture a major portion of the dynamic correlation effects, accurately reproducing the experimental magnetic coupling constant (J) of [Fe{sub 2}OCl{sub 6}]{sup 2−} with (16e,26o), and considerably improving the smaller active space results for [Cr{sub 2}O(NH{sub 3}){sub 10}]{sup 4+} with (12e,32o). For comparison, we perform conventional MRCI+Q calculations and find the J values to be consistent with those from DMRGCASSCF. In contrast to previous studies, the higher spin states of the two systems show similar deviations from the Heisenberg spectrum, regardless of the computational method.},
doi = {10.1063/1.4863345},
journal = {Journal of Chemical Physics},
number = 5,
volume = 140,
place = {United States},
year = 2014,
month = 2
}

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