Weak Temperature Dependence in the Magnetic Circular Dichroism of Matrix-Isolated Copper Phthalocyanine

Dunford, Cara L.; Williamson, Bryce E.

doi:10.1021/jp962394f

Cited by 11 publications

(23 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, this physically implausible state is higher in energy than the depicted configuration, both because the d x 2 −y 2 orbital is less stable than the ligand HOMO and because it is harder to pair electrons within the more compact metal-centred orbital. This analysis is supported by previous experimental [77,78,79,80,81] and computational [82,77,78,83,18,79,84] studies that agree on the ground state configuration shown in Figure 2.…”

Section: Nipc Cupc Znpcsupporting

confidence: 86%

CASSCF-based explicit ligand field models clarify the ground state electronic structures of transition metal phthalocyanines (MPc; M = Mn, Fe, Co, Ni, Cu, Zn)

2016

Self Cite

View full text Add to dashboard Cite

Multireference electronic structure methods are used to assign ground state electronic configurations for a series of metallophthalocyanines. Ligand orbital occupancies remain constant across the period and are consistent with a formal 2– charge on the ligand. The d electron configurations of some metallophthalocyanines are straightforward and can be unambiguously assigned, (dxy)2(dxz,dyz)2,2( [Formula: see text])2([Formula: see text])n, with n = 2, 1, 0, respectively, for ZnPc, CuPc, and NiPc. Controversies over ground state electronic structure assignments for other metallophthalocyanines arise due to multiple complicating factors: accidental near-degeneracies, environmental effects, and different ligand field models used in interpreting experimental spectra. We demonstrate that explicit ligand field models provide more reliable and consistent interpretations of experimental data than implicit, parameterized alternatives. On this basis, we assign gas-phase electronic ground states for MnPc, (dxy)2(dxz,dyz)1,1([Formula: see text])1 and CoPc, (dxy)2(dxz,dyz)2,2([Formula: see text])1, and show that the ground state of FePc cannot be resolved to a single state, with two near-degenerate states that are likely spin-orbit coupled: (dxy)2(dxz,dyz)1,1( [Formula: see text])2 and (dxy)2(dxz,dyz)2,1([Formula: see text])1. Remaining differences between computational predictions and experimental observations are small and may be ascribed primarily to environmental effects but are also partly due to incomplete modelling of electron correlation.

show abstract

Section: Nipc Cupc Znpcsupporting

confidence: 86%

CASSCF-based explicit ligand field models clarify the ground state electronic structures of transition metal phthalocyanines (MPc; M = Mn, Fe, Co, Ni, Cu, Zn)

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…54 In contrast to all of the previous examples considered here, even at very low temperatures the MCD of the Q-band is only very weakly temperature dependent. 54 In contrast to all of the previous examples considered here, even at very low temperatures the MCD of the Q-band is only very weakly temperature dependent.…”

Section: Cu Phthalocyaninecontrasting

confidence: 62%

“…54 In contrast to all of the previous examples considered here, even at very low temperatures the MCD of the Q-band is only very weakly temperature dependent. 54 The experimental and simulated spectra of CuPhth are presented in Fig. 54 From an analysis of the temperature dependence of the MCD intensity for this state is found to be 1.5 cm −1 .…”

Section: Cu Phthalocyaninecontrasting

confidence: 62%

See 1 more Smart Citation

Application of magnetically perturbed time-dependent density functional theory to magnetic circular dichroism. III. Temperature-dependent magnetic circular dichroism induced by spin-orbit coupling

Seth

Ziegler

Autschbach

2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

A methodology for calculating the temperature-dependent magnetic circular dichroism (MCD) of open-shell molecules with time-dependent density functional theory (TDDFT) is described. The equations for the MCD of an open-shell molecule including spin-orbit coupling in the low- and high-temperature limits are reviewed. Two effects lead to the temperature-dependent MCD: the breaking of degeneracies and the perturbation of transition dipoles by spin-orbit coupling. The equations necessary to evaluate the required terms using TDDFT-derived quantities are presented. The performance of the formalism is demonstrated through application to the MCD of several molecules. The spectra of these molecules have differing properties with respect to bandwidth, temperature dependence of the MCD, and relative magnitude of the temperature-dependent and temperature-independent components of the MCD. The important features of the experimental spectra are reproduced by the calculations.

show abstract

“…Q 00 at 736 nm corresponds to the a 1 u ( π ) → e g ( π * ) transition at the HOMO-LUMO gap and is polarized in the plane of the molecule. Q 10 at 696 nm is the contribution of vibrational overtones and Q 20 located at 658 nm can be assigned as a transition from lower lying σ states in the valence band manifold ( e u ( σ ) → e g ( π * )), polarized perpendicular to the molecular plane and vibronically coupled to Q 00 43 . Absorption spectrum of the Cu-OBPc thin films is significantly broadened compared to that of the solution due to the Davydov splitting and excitonic coupling in the crystalline phase that leads to more complex band structure 39 44 .…”

Section: Resultsmentioning

confidence: 99%

Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films

Rawat

Pan

Lamarche

et al. 2015

Sci Rep

View full text Add to dashboard Cite

The origins of spin exchange in crystalline thin films of Copper Octabutoxy Phthalocyanine (Cu-OBPc) are investigated using Magnetic Circular Dichroism (MCD) spectroscopy. These studies are made possible by a solution deposition technique which produces highly ordered films with macroscopic grain sizes suitable for optical studies. For temperatures lower than 2 K, the contribution of a specific state in the valence band manifold originating from the hybridized lone pair in nitrogen orbitals of the Phthalocyanine ring, bears the Brillouin-like signature of an exchange interaction with the localized d-shell Cu spins. A comprehensive MCD spectral analysis coupled with a molecular field model of a σπ − d exchange analogous to sp-d interactions in Diluted Magnetic Semiconductors (DMS) renders an enhanced Zeeman splitting and a modified g-factor of −4 for the electrons that mediate the interaction. These studies define an experimental tool for identifying electronic states involved in spin-dependent exchange interactions in organic materials.

show abstract

Weak Temperature Dependence in the Magnetic Circular Dichroism of Matrix-Isolated Copper Phthalocyanine

Cited by 11 publications

References 23 publications

CASSCF-based explicit ligand field models clarify the ground state electronic structures of transition metal phthalocyanines (MPc; M = Mn, Fe, Co, Ni, Cu, Zn)

CASSCF-based explicit ligand field models clarify the ground state electronic structures of transition metal phthalocyanines (MPc; M = Mn, Fe, Co, Ni, Cu, Zn)

Application of magnetically perturbed time-dependent density functional theory to magnetic circular dichroism. III. Temperature-dependent magnetic circular dichroism induced by spin-orbit coupling

Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films

Contact Info

Product

Resources

About