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Estimation of electronic coupling for singlet excitation energy transfer

Electronic coupling is a key parameter that controls the efficiency of excitation energy transfer (EET) and exciton delocalization. A new approach to estimate electronic coupling is introduced. Within a two-state model, the EET coupling V of two chromophores is expressed via the vertical excitation energies (Ei and Ej), transition dipole moments (Mi and Mj) of the system and transition moments (μA and μB) of the individual chromophores: V = (Ei -E j){[(MiMj)(μA 2 -μB 2) -(μAμB)(M i 2 -Mj 2)]/[(Mi 2 -Mj 2)2 + 4(MiM j)2]}. These quantities are directly available from quantum mechanical calculations. As the estimated coupling accounts for both short-range and long-range interactions, this approach allows for the treatment of systems with short intermolecular distances, in particular, π-stacked chromophores. For a system of two identical chromophores, the coupling is given by V = (Ei -Ej)[(EiFj -E jFi)/(EiFj + EjF i)][1/(2 cos θ)] where Fi and Fj are the corresponding oscillator strengths and cos θ is determined by the relative position of the chromophores in the dimer. Thus, the coupling can be derived from purely experimental data. The developed approach is used to calculate the EET coupling and exciton delocalization in two π-stacks of pyrimidine nucleobases 5′-TT-3′ and 5′-CT-3′ showing quite different EET properties

Financial support from MICINN (Ministry of Science and Innovation, Spain) was provided by grant CTQ 2011-26573

American Chemical Society (ACS)

Manager: Ministerio de Ciencia e Innovación (Espanya)
Author: Voityuk, Alexander A.
Abstract: Electronic coupling is a key parameter that controls the efficiency of excitation energy transfer (EET) and exciton delocalization. A new approach to estimate electronic coupling is introduced. Within a two-state model, the EET coupling V of two chromophores is expressed via the vertical excitation energies (Ei and Ej), transition dipole moments (Mi and Mj) of the system and transition moments (μA and μB) of the individual chromophores: V = (Ei -E j){[(MiMj)(μA 2 -μB 2) -(μAμB)(M i 2 -Mj 2)]/[(Mi 2 -Mj 2)2 + 4(MiM j)2]}. These quantities are directly available from quantum mechanical calculations. As the estimated coupling accounts for both short-range and long-range interactions, this approach allows for the treatment of systems with short intermolecular distances, in particular, π-stacked chromophores. For a system of two identical chromophores, the coupling is given by V = (Ei -Ej)[(EiFj -E jFi)/(EiFj + EjF i)][1/(2 cos θ)] where Fi and Fj are the corresponding oscillator strengths and cos θ is determined by the relative position of the chromophores in the dimer. Thus, the coupling can be derived from purely experimental data. The developed approach is used to calculate the EET coupling and exciton delocalization in two π-stacks of pyrimidine nucleobases 5′-TT-3′ and 5′-CT-3′ showing quite different EET properties
Financial support from MICINN (Ministry of Science and Innovation, Spain) was provided by grant CTQ 2011-26573
Document access: http://hdl.handle.net/2072/297359
Language: eng
Publisher: American Chemical Society (ACS)
Rights: Tots els drets reservats
Subject: Excitació nuclear
Nuclear excitation
Química de l’estat excitat
Excited state chemistry
Química quàntica
Quantum chemistry
Title: Estimation of electronic coupling for singlet excitation energy transfer
Type: info:eu-repo/semantics/article
Repository: Recercat

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