Metal phthalocyanine ground states: covalence and ab initio calculation of spin and charge densities

Reynolds, P. A.; Figgis, Brian N.

doi:10.1021/ic00010a015

Cited by 100 publications

(97 citation statements)

References 2 publications

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“…Thus, the imposition of the constraints on the density matrix provides an approach that permits the calculation of states that may be difficult to stabilize otherwise, independent of the initial densities. These results indicate that different solutions proposed previously [16][17][18][19][20][21] may be sensitive to (or an accidental result of) calculational details.…”

Section: Resultsmentioning

confidence: 76%

“…Similarly, DFT calculations are still contradictory: recent pseudo-potential and full-potential linearized augmented plane wave (FLAPW) calculations [16][17][18] within the generalized gradient approximation (GGA) support the 3 E g ground state, in which qualitative agreement with experimental observations is obtained for α-FePc 9 , but the 3 A 2g or 3 B 2g ground state have also been found [19][20][21] . Unfortunately, up to now there have not been direct comparisons of the total energies of the various multiplets within a DFT scheme.…”

Section: Structure Of Fe-phthalocyaninementioning

confidence: 99%

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Constraint density functional calculations for multiplets in a ligand-field applied to Fe-phthalocyanine

et al. 2012

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Multiplets in a ligand-field are treated within total-energy density functional calculations by imposing density matrix constraints on the d-orbital occupation numbers consistent with the local site and state symmetries. We demonstrate the utility of this approach for the case of isolated Fe phthalocyanine (FePc) molecules with overall D 4h symmetry: We find three stationary states of 3 Eg, 3 A2g, and 3 B2g symmetries of the Fe 2+ ion and total energy calculations clearly demonstrate that the ground state is 3 A2g. By contrast, a columnar stacking of the FePc molecules (α-FePc) is found to change the ground state to 3 Eg due to hybridization between adjacent molecules.

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Section: Resultsmentioning

confidence: 76%

Section: Structure Of Fe-phthalocyaninementioning

confidence: 99%

Constraint density functional calculations for multiplets in a ligand-field applied to Fe-phthalocyanine

et al. 2012

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“…[1][2][3][4][5] Moreover, a challenge to miniaturize devices for novel magnetic applications now extends to treating an extreme limit of the single molecule. Importantly, the property of the MPc is governed by the electronic structure, so-called multiplet, which arises from the d-orbitals localized at the transition-metal atom.…”

Section: Introductionmentioning

confidence: 99%

“…For examples, for the FePc, experiments [6][7][8][9] have individually proposed the 3 E g and either 3 B 2g or 3 A 2g state, and even the density functional theory (DFT) calculations have predicted contradictory. 2,[10][11][12][13][14] For the MnPc, the multiplet for ground state has been suggested either 4 E g or 4 B 2g state, 11,15,16 and for the CoPc, the 2 E g or 2 A 1g state. 11,13 For this, we previously proposed a constraint DFT approach, implemented in the full-potential linearized augmented plane-wave (FLAPW) method, 17 by imposing density matrix constraints on the d-orbitals occupation numbers, and our total energy calculations demonstrate that for the FePc, there are three stationary states of the 3 E g , 3 B 2g , and 3 A 2g symmetries and that the ground state is the 3 A 2g state with a planar magnetic anisotropy (MA).…”

Section: Introductionmentioning

confidence: 99%

Magnetism and multiplets in metal-phthalocyanine molecules

Kitaoka

Sakai

Nakamura

et al. 2013

Journal of Applied Physics

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Magnetism and multiplets for metal-phthalocyanine (MPc) molecules with transition-metals (M) of Mn and Co were investigated based on the constraint density functional theory calculations by imposing density matrix constraint on the d-orbital occupation numbers. For the MnPc, the ground state is found to be the 4 E g state with the perpendicular magnetic anisotropy with respect to the molecular plane, while for the CoPc, the ground state is the 2 A 1g state with a planar magnetic anisotropy. V C 2013 American Institute of Physics. [http://dx

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“…11 However, uncertainties still exist regarding the role of excited states mixed into the ground state. 11,18,20 Here, taking advantage of XAS and XMCD simulations at low temperature, we are able to provide a description of the molecule electronic structure that settles previous ambiguities. Simulated spectra from ligand field multiplet calculations are shown in Fig.…”

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confidence: 99%

Mixed-valence behavior and strong correlation effects of metal phthalocyanines adsorbed on metals

et al. 2011

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We investigate the hierarchy of local correlation and hybridization effects in metal-organic molecules adsorbed on metals. Using x-ray magnetic circular dichroism and ligand field multiplet calculations, we demonstrate that the 3d electronic ground state of monolayer metal-phthalocyanine (CoPc, FePc) on Au (111) is given by the coherent superposition of two charge states, d n E + d n+1 , where E represents a substrate electron antiferromagnetically coupled to the central metal ion and d n the many-body ionic orbital configuration of the unperturbed molecule. These results differ from previous models of hybrid metal-organic systems and provide a consistent description of their magnetic moments and Kondo physics in terms of spin and orbital multiplicity. The magnetic properties of transition-metal (TM) compounds depend critically on the competition between d-d electron correlation and covalency, that is, the transfer of charge between d-orbitals and delocalized ligand states. 1 Charge transfer (CT) affects the magnetization of TM ions, their coupling through indirect exchange paths, as well as the conductivity of important classes of materials, including TM oxides, high-T c superconductors, and molecular complexes. Recently, CT processes that take place at the interface between magnetic molecules and metal surfaces have come under intensive attention. 2-4 Transport measurements of single molecules trapped between metallic electrodes 5 and layered metal/organic heterostructures 6 have revealed the role played by interfacial hybridization in determining efficient charge and spin injection across TM complexes, a prerequisite to developing molecular spintronic devices. 6,7 A comprehensive description of the electronic and magnetic properties of metal-organic hybrids, however, is complicated by the fact that CT can occur between TM and ligand orbitals, but also between any of these states and the electron reservoir of a supporting metal surface or electrode. Clearly, understanding such processes would be of great importance in modeling and controlling the properties of magnetic molecules interfaced with metals.Density functional theory (DFT) provides the basis of our current understanding of hybrid metal-organic systems. [2][3][4]8,9 Yet, due to the difficulty of modeling exchange and electron correlation phenomena using effective one-electron potentials, DFT affords only a partial description of the magnetic properties of TM complexes. 1 Methods beyond standard DFT that include Coulomb repulsion through semiempirical Hubbard U terms have been successfully employed to describe the ground state of isolated molecules. 10 However, DFT + U remains a mean-field scheme, which precludes a proper modeling of valence and spin fluctuations induced by CT.A notable case where CT has a dramatic influence on the magnetism of a TM complex is that of Co-phthalocyanine (CoPc), a well-known molecule with spin S = 1/2 (Ref. 11).DFT predicts that CoPc adsorbed on Au(111) (Refs. 12 and 13), Cu (111) (Ref. 14), and even ferromagnetic Fe(110...

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Metal phthalocyanine ground states: covalence and ab initio calculation of spin and charge densities

Cited by 100 publications

References 2 publications

Constraint density functional calculations for multiplets in a ligand-field applied to Fe-phthalocyanine

Constraint density functional calculations for multiplets in a ligand-field applied to Fe-phthalocyanine

Magnetism and multiplets in metal-phthalocyanine molecules

Mixed-valence behavior and strong correlation effects of metal phthalocyanines adsorbed on metals

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