Electronic structure and bonding in metal phthalocyanines, Metal=Fe, Co, Ni, Cu, Zn, Mg

Liao, Meng‐Sheng; Scheiner, Steve

doi:10.1063/1.1367374

Cited by 590 publications

(653 citation statements)

References 48 publications

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“…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: 54%

“…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: 70%

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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: Structure Of Fe-phthalocyaninementioning

confidence: 54%

Section: Resultsmentioning

confidence: 70%

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

et al. 2012

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“…Theoretical calculations predict that the configuration having both electrons in the Cu 3d orbital is in fact the first excited state of the CuPc − ion, the ground state being formed with one electron in the Cu 3d orbital and one in the LUMO of the Pc molecule. 23 We attribute the two observed muon signal components in muoniated CuPc molecules to the formation of these two configurations, the ͑3d͒ 1 ͑LUMO͒ 1 ground state and the ͑3d͒ 2 first excited state, by the lone Cu electron and the muonium's electron. In spin terms, the two electrons always pair, forming an S = 0 spin state independently of the spatial configuration.…”

Section: Diamagnetic States: Cupcmentioning

confidence: 99%

“…This would favor the anchoring of muonium to that nitrogen in a dative-bond way, leaving the conjugated structure of the inner carbon-nitrogen ring untouched and a nearby unpaired electron. Since the lowest unoccupied molecular orbital ͑LUMO͒ of phthalocyanines is predominantly made up from atomic orbitals belonging to that ring, 22,23 the lingering electron would assume a spatial configuration similar to the LUMO and become more delocalized than in the cases of states I or II.…”

Section: B Paramagnetic States: Electronic Structure Calculationsmentioning

confidence: 99%

Muoniated radical states in the organic semiconductor phthalocyanine

et al. 2006

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Phthalocyanine samples of ZnPc, H 2 Pc, and CuPc were investigated with the muon spin rotation technique. In ZnPc and H 2 Pc, three muoniated radical states of paramagnetic origin were identified, two of which have hyperfine interactions in the range 110-150 MHz and correspond to muonium addition at the outer benzene rings. The third state has a smaller hyperfine interaction ͑about 25 MHz͒ and is tentatively assigned to addition at bridging nitrogen atoms. CuPc has an unpaired electron from the Cu atom, which originates a diamagneticlike signal upon muonium addition. The signal has two components with very different relaxation rates, corresponding to two different spatial couplings of the Cu electron with the muonium's electron.

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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.…”

mentioning

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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Electronic structure and bonding in metal phthalocyanines, Metal=Fe, Co, Ni, Cu, Zn, Mg

Cited by 590 publications

References 48 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

Muoniated radical states in the organic semiconductor phthalocyanine

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

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