Use of the neighboring orbital model for analysis of electronic coupling in Class III intervalence compounds

Nelsen, Stephen F.; Weaver, Michael N.; Luo, Y. X.; Lockard, Jenny V.; Zink, Jeffrey I.

doi:10.1016/j.chemphys.2006.01.023

Cited by 31 publications

(62 citation statements)

References 39 publications

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“…As a result, all reported reorganization energies obtained using classic analytical expressions for the charge-localized limit (Allen & Hush 1967) are underestimated by typically 1000-2000 cm K1 ; this deficiency is in addition to others found associated with the use of only a two-site model to describe the complex electronic interactions (Nelson et al 2006) and is a general effect for the Creutz-Taube ion obtained using model B, as shown in figure 4. The calculated electronic band contour, along with any associated phase-phonon vibrational activity, is shown as a function of 2J/l T in figure 4.…”

Section: Simulation Of the Intervalence Charge-transfer Electronic Abmentioning

confidence: 98%

Towards a comprehensive model for the electronic and vibrational structure of the Creutz–Taube ion

Reimers

Wallace

Hush

2007

Phil. Trans. R. Soc. A.

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Since the synthesis of the Creutz-Taube ion, the nature of its charge localization has been of immense scientific interest, this molecule providing a model system for the understanding of the operation of biological photosynthetic and electron-transfer processes. However, recent work has shown that its nature remains an open question. Many systems of this type, including photosynthetic reaction centres, are of current research interest, and thereby the Creutz-Taube ion provides an important chemical paradigm: the key point of interest is the details of how such molecules behave. We lay the groundwork for the construction of a comprehensive model for its chemical and spectroscopic properties. Advances are described in some of the required areas including: simulation of electronic absorption spectra; quantitative depiction of the large interaction of the ion's electronic description with solvent motions; and the physics of Ru-NH 3 spectator-mode vibrations. We show that details of the solvent electron-phonon coupling are critical in the interpretation of the spectator-mode vibrations, as these strongly mix with solvent motions when 0.75!2J/l!1. In this regime, a double-well potential exists which does not support localized zero-point vibration, and many observed properties of the Creutz-Taube ion are shown to be consistent with the hypothesis that the ion has this character.

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Section: Simulation Of the Intervalence Charge-transfer Electronic Abmentioning

confidence: 98%

Towards a comprehensive model for the electronic and vibrational structure of the Creutz–Taube ion

Reimers

Wallace

Hush

2007

Phil. Trans. R. Soc. A.

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“…Even weaker coupling is found for 3, for which the ground state redox process is calculated (and found experimentally 67 ) to occur at the P sites, with a higher energy Ru 2+ /Ru 3+ redox process. (2) values; 13,18,19,22,33,40,52 that is, the many-electron diabatic matrix element of H (H DA ) may to good approximation (i.e., typically within ∼10% 13 ) be represented by the diabatic orbital matrix element (h DA ) of an effective 1-e Hamiltonian h (see section II). Furthermore, sample comparisons of coupling from the 1-e model (based on (Ru-pz-Ru) 4+ orbitals) and direct SCF calculations for the 5+ complexes show reasonable agreement.…”

Section: /E)mentioning

confidence: 99%

“…The relevant D and A manifold also must take adequate account of the role of any intervening bridge states (B). 13,14,16,22,32,34,35 Quantitative means of assessing the degree to which this criterion is satisfied are considered below over a range of n values for a given ET system. The spaces adopted here are based on in vacuo adiabatic states, but may also be defined as in situ spaces (e.g., in the presence of a variable solvent reaction field).…”

Section: Electronic States and Spacesmentioning

confidence: 99%

“…What is the most appropriate reduced electronic space (n g 2) for modeling ET processes? When is the 2-st model adequate, bearing in mind the debate and analysis in the recent literature (Bixon et al, 28 Gould et al, 29 Cave and Newton, 31 Rust et al, 25 Voityuk, 18,19 Lambert et al, 20,21 and Nelsen et al 22 )? What is the appropriate set of states, either adiabatic (eigenstates) or diabatic states (initial, final, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…Although the two-state approximation (TSA) may be adequate if the two states are sufficiently separated energetically from other solute states, 16 it has frequently been noted that a larger set of electronic states may be necessary, especially when molecular spacers with low-lying states are interposed between D and A sites (as in bridge-mediated (DBA) intramolecular ET) [17][18][19][20][21][22][23] or when more than one state on a given D or A site must be considered (e.g., a ground (G) and locally excited (LE) state, D* or A*). 24,25 For , which may involve exciplex formation) 27 )susing the appropriate 2-st models in a pairwise fashion.…”

Section: Introductionmentioning

confidence: 99%

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Reduced Electronic Spaces for Modeling Donor/Acceptor Interactions

et al. 2010

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Diabatic states for donor (D) and acceptor (A) interactions in electron transfer (ET) processes are formulated and evaluated, along with coupling elements (H DA ) and effective D/A separation distances (r DA ), for reduced electronic spaces of variable size, using the generalized Mulliken Hush model (GMH), applicable to an arbitrary state space and nuclear configuration, and encompassing Robin-Day class III and as well as class II situations. Once the electronic state space is selected (a set of n g 2 adiabatic states approximated by an orbital space based on an effective 1-electron (1-e) Hamiltonian), the charge-localized GMH diabatic states are obtained as the eigenstates of the dipole moment operator, with rotations to yield locally adiabatic states for sites with multiple states. The 1-e states and energies are expressed in terms of Kohn-Sham orbitals and orbital energies. Addressing questions as to whether the estimate of H DA "improves" as one increases n, and in what sense the GMH approach "converges" with n, we carry out calculations for three mixed-valence binuclear Ru complexes, from which we conclude that the 2-state (2-st) model gives the most appropriate estimate of the effectiVe coupling, similar (to within a rms deviation of e15%) to coupling elements obtained by superexchange correction of H DA values based on larger spaces (n ) 3-6), and thus yielding a quasi-invariant value for H DA over the range explored in the calculations (n ) 2-6). An analysis of the coupling and associated D and A states shows that the 2-st coupling involves crucial mixing with intervening bridge states (D and A "tails"), while increasingly larger state spaces for the same system yield increasingly more localized D and A states (and weaker coupling), with H DA tending to approach the limit of "bare" or "through space" coupling. These results help to reconcile seemingly contradictory assertions in the recent literature regarding the proper role of multistate frameworks in the formulation of coupling for both intra-and intermolecular ET systems.The present results are compared in detail with other reported results.

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Intramolecular π‐Stacking Interactions of Bridged Bis‐p‐Phenylenediamine Radical Cations and Diradical Dications: Charge‐Transfer versus Spin‐Coupling

Jalilov¹,

Nelsen²,

Guzei³

et al. 2011

Angewandte Chemie

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Allen Widrigkeiten zum Trotz: Eine verbrückte gemischtvalente Verbindung mit direkten Through‐Space‐Wechselwirkungen zwischen den geladenen Einheiten wurde in ihrer einfach geladenen paramagnetischen und doppelt geladenen diamagnetischen Form isoliert (siehe Schema). Trotz der Coulomb‐Abstoßung waren im diradikalischen Singulett‐Dikation die π‐Stapelwechselwirkungen stärker ausgeprägt als beim Dublett‐Monokation.

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Use of the neighboring orbital model for analysis of electronic coupling in Class III intervalence compounds

Cited by 31 publications

References 39 publications

Towards a comprehensive model for the electronic and vibrational structure of the Creutz–Taube ion

Towards a comprehensive model for the electronic and vibrational structure of the Creutz–Taube ion

Reduced Electronic Spaces for Modeling Donor/Acceptor Interactions

Intramolecular π‐Stacking Interactions of Bridged Bis‐p‐Phenylenediamine Radical Cations and Diradical Dications: Charge‐Transfer versus Spin‐Coupling

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