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  • 1
    Electronic Resource
    Electronic Resource
    On the rate of radiationless intermolecular energy transfer (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 7405-7413 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The effects of higher multipole interactions (up to electric quadrupole–quadrupole) and small exchange contributions on the rate of intermolecular energy transfer are examined. Second-order Coulombic interactions are described within a molecular quantum electrodynamical framework. A correction due to a small first-order exchange mechanism is then proposed. It is concluded that use of the multipole expansion in the interaction Hamiltonian is not always a good approximation at interchromophore separations of less than about 10 A(ring). This is attributed to a combination of large molecular dimensions compared to intermolecular separation, and wave function overlap effects. For larger separations, the interaction is described well by the usual dipolar coupling formalism. The inclusion of small exchange effects in a simplistic model at small to intermediate separations demonstrates the likelihood of a substantially greater rate of energy transfer than that predicted by either a Förster-type (dipole–dipole) or a purely exchange-type mechanism. The relevance to the photophysics of multichromophoric systems, such as aromatic polymers, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.463512
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  • 2
    Electronic Resource
    Electronic Resource
    Configuration interaction and the theory of electronic factors in energy transfer and molecular exciton interactions (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 5054-5061 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The theory established in J. Chem. Phys. 101, 10521 (1994), for electronic factors which promote interchromophore electronic energy transfer, exciton interactions and which provide the stabilization of excimers, is extended; first so as to include the possible contribution of doubly excited configurations. It is ascertained that there is a resultant effect upon the (interchromophore orbital overlap-dependent) through-configuration interaction, and a significant correction to the simple expression obtained previously for the Coulombic interaction. These CI effects are admitted to the general theory of the previous work and the cases of nonidentical, identical, and orthogonal donor and acceptor are discussed. Second, a description of superexchange effects is admitted to the theory. Two possible formalisms are developed and discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471135
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  • 3
    Electronic Resource
    Electronic Resource
    Rate expressions for excitation transfer. II. Electronic considerations of direct and through–configuration exciton resonance interactions (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 10521-10525 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The electronic interactions which promote singlet–singlet and triplet–triplet electronic excitation (energy) transfer (EET) are investigated in detail. Donor and acceptor locally excited configurations, ψ1(A*B) and ψ4(AB*), respectively, are each allowed to mix with bridging ionic configurations, ψ2(A+B−) and ψ3(A−B+) to form the new donor and acceptor wave functions ΨR=ψ1+λψ2+μψ3 and ΨP=ψ4+μψ2+λψ3. Use of the latter wave functions leads to the establishment of the matrix element TRP= 〈ΨR||H−E1||ΨP〉≈T14−(T12T24+T 13T34)/A, with Tij=〈ψi||H−E1||ψj〉 and A=E2−E1, as the exciton resonance interaction term for EET. Introduction of the Mulliken approximation shows that the "direct'' exciton resonance interaction term (T14) contributes primarily a Coulombic interaction, for singlet–singlet EET, while the "through–configuration'' exciton resonance interaction term [−(T12T24+T13T34)/A] replaces the Dexter exchange integral (which is a component of H14) as the primary source of short-range orbital overlap-dependent EET. The origins of "Dexter-type'' energy transfer are thus shown to be quite different from that originally outlined. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467869
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  • 4
    Electronic Resource
    Electronic Resource
    Rate expressions for excitation transfer. IV. Energy migration and superexchange phenomena (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 8873-8883 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: General microscopic mechanisms of electronic excitation (energy) transfer (EET) in multichromophoric assemblies are investigated. Aspects of superexchange-mediated EET and energy migration (EM) and their contribution to the efficiency of donor-to-trap energy transport processes in macromolecules are discussed from a quantum mechanical viewpoint. The possibility of superexchange pathways for EM via higher excited states of the intermediate chromophores is introduced. The role of quasicoherent EM pathways, and how they are manifested in the quantum mechanical rate expression, is investigated and the significance of contributions to the rate arising through quantum mechanical interference between pathways is elucidated. The theory indicates conditions under which coherent EM pathways may significantly increase the efficiency of energy transport and trapping and the applications to natural and synthetic light-harvesting systems are outlined. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.470076
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  • 5
    Electronic Resource
    Electronic Resource
    Rate expressions for excitation transfer. III. An ab initio study of electronic factors in excitation transfer and exciton resonance interactions (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 9574-9581 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A detailed theory for electronic aspects of electronic excitation (energy) transfer (EET) for sandwich dimers was derived in paper II of this series [J. Chem. Phys. 101, 10 521 (1994)]. In II, the electronic transfer matrix element for EET was evaluated, then simplified to various levels of approximation. The results of ab initio molecular orbital calculations on an ethene sandwich dimer are reported here in order to test and quantify the theory of II. The calculations were undertaken using a STO-6G basis set and localized molecular orbitals, with separations of 4, 5, and 6 A(ring) between the molecules. It is demonstrated that the important electronic factors contributing to EET are the Coulombic interaction (for direct singlet–singlet transfer) and, for both singlet–singlet and triplet–triplet EET, orbital overlap-dependent interactions. The dominant orbital overlap-dependent terms arise from through-configuration interaction, which involves successive one-electron transfers mediated via bridging ionic configurations, first presented in II. The results confirm that the Dexter-type exchange interaction is small in comparison. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.468773
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  • 6
    Electronic Resource
    Electronic Resource
    Rate expressions for excitation transfer I. Radiationless transition theory perspective (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 1251-1261 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ideas concerning preparation of an initial state and its subsequent temporal evolution are discussed with reference to interchromophore electronic excitation (energy) transfer (EET), particularly the "resonance'' case. The cases of strong and weak coupling, and their consequences, are discussed. It is shown that when the interactions between two identical chromophores lie in the weak coupling regime, then a rate of excitation transfer may be defined on an experimental time scale and is given by a Fermi golden rule expression; the quasicontinuous final state being provided primarily by nonradiative line broadening. In general, such a rate expression applies so long as the donor–acceptor electronic coupling is less than the vibronic band width. The strong coupling limit is shown to result in excimer or exciplex-type emission. A rate equation formalizing donor–acceptor EET in general is determined by consideration of the Green's function methods of scattering theory. The role of nuclear coordinates, including the possibility of Herzberg–Teller coupling, and the influence of nonradiative processes are examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467817
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  • 7
    Electronic Resource
    Electronic Resource
    Intramolecular electronic energy transfer between rigidly linked naphthalene and anthracene chromophores (1993)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 97 (1993), S. 11871-11876 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100148a006
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  • 8
    Electronic Resource
    Electronic Resource
    Electronic Interactions and Interchromophore Excitation Transfer (1994)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 98 (1994), S. 4580-4590 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100068a017
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  • 9
    Electronic Resource
    Electronic Resource
    On the origin of matrix elements for electronic excitation (energy) transfer (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 1897-1901 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The origin of electronic energy transfer (EET) between two chromophores (D and A) is explored further for several molecular situations that may be encountered in experiment—namely, nonoverlapping active-space orbitals of the D and A chromophores, forbidden electronic excitations for both chromophores, and an allowed and a forbidden electronic excitation for the D and A chromophores, respectively. The theory is illustrated via the results of calculations of the EET matrix elements for model systems with both four–eight active-space electrons and all of the electrons included explicitly. In each case, it is found that any overlap contribution to these matrix elements is associated much more with charge-transfer and penetration terms rather than it is with the Dexter exchange integral. The calculated magnitude of the latter integral is always smaller than that of the Coulomb integral. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.472060
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  • 10
    Electronic Resource
    Electronic Resource
    LONG-RANGE RESONANCE ENERGY TRANSFER IN MOLECULAR SYSTEMS (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physical Chemistry 54 (2003), S. 57-87 
    Details
    ISSN: 0066-426X
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The current state of understanding of molecular resonance energy transfer (RET) and recent developments in the field are reviewed. The development of more general theoretical approaches has uncovered some new principles underlying RET processes. This review brings many of these important new concepts together into a generalization of Forster's original theory. The conclusions of studies investigating the various approximations in Forster theory are summarized. Areas of present and future activity are discussed. The review covers Forster theory for donor-acceptor pairs and electronic coupling for singlet-singlet, triplet-triplet, and superexchange-mediated energy transfer. This includes the transition density picture of Coulombic coupling as well as electronic coupling between molecular aggregates (excitons). Spectral overlaps and ensemble energy transfer rates in disordered aggregates, the role of dielectric properties of the medium, weak versus strong coupling, and new models for energy transfer in complex molecular assemblies are also described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.physchem.54.011002.103746
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