UNO DMRG CAS CI calculations of binuclear manganese complex Mn(IV)2 O2 (NHCHCO2 )4 : Scope and applicability of Heisenberg model

Takashi Kawakami; Koichi Miyagawa; Sandeep Sharma; Toru Saito; Mitsuo Shoji; Satoru Yamada; Shusuke Yamanaka; Mitsutaka Okumura; Takahito Nakajima; Kizashi Yamaguchi

doi:10.1002/jcc.25602

UNO DMRG CAS CI calculations of binuclear manganese complex Mn(IV)₂ O₂ (NHCHCO₂ )₄ : Scope and applicability of Heisenberg model

J Comput Chem. 2019 Jan 15;40(2):333-341. doi: 10.1002/jcc.25602. Epub 2018 Oct 20.

Authors

Takashi Kawakami^{1

2}, Koichi Miyagawa³, Sandeep Sharma⁴, Toru Saito⁵, Mitsuo Shoji⁶, Satoru Yamada³, Shusuke Yamanaka¹, Mitsutaka Okumura¹, Takahito Nakajima², Kizashi Yamaguchi^{1

2

3

7}

Affiliations

¹ Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
² Riken Center for Computational Science, Kobe, Hyogo, 650-0047, Japan.
³ The Institute of Scientific and Industrial Research, Osaka University, Osaka, Ibaraki, 567-0047, Japan.
⁴ Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, 80309.
⁵ Graduate School of Information Sciences, Hiroshima City University, Hiroshima, 731-3194, Japan.
⁶ Center of Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
⁷ NanoScience Design Center, Osaka University, Toyonaka, Osaka, 560-8531, Japan.

PMID: 30341945
DOI: 10.1002/jcc.25602

Abstract

Both direct exchange and super-exchange interactions cooperate to realize inter-spin magnetic interaction in binuclear manganese complex Mn(IV)₂ O₂ (NHCHCO₂ )₄ with a di-μ-oxo path. We revisited this spin system using DMRG CAS methods and CAS selection procedures. Our results indicate that our previous "dynamically extended spin polarization" (DE-SP) procedure for organic polyradicals and so forth does not work well. Thus, we have examined another selection procedure, the "dynamically extended super-exchange" (DE-SE) procedure. DMRG CASCI [18,18] by UB3LYP(HS)-UNO(DE-SE) can realize antiferromagnetic J values similar to experimental ones (-87 cm^-1 ). In addition, all J values between all spin states (HS[septet],IS[quintet],IS[triplet],LS[singlet])were also shown to be correct under sufficiently large M values. © 2018 Wiley Periodicals, Inc.

Keywords: CaMn4O5 cluster; DMRG CAS; active orbital selection; binuclear manganese complex; magnetic interaction.

Abstract

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