ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
We report here a theoretical formulation of the transport of excitation energy in a three-dimensional molecular crystal containing one impurity. The excitation is assumed to be localized in the jth site at time t, and the expression for the probability of finding the excitation at some other site j′ at a later time t′ is derived. The probability is given by the correlation function \documentclass{article}\pagestyle{empty}\begin{document}$ \left\langle {\hat P_j (t)\hat P_j (0)} \right\rangle $\end{document}, where \documentclass{article}\pagestyle{empty}\begin{document}$ \left\langle {\hat P_m } \right\rangle $\end{document} represents the site projection operator, |m〉 〈m|. In our derivation we neglect the interaction among excitons of different bands, account for the presence of the impurity by adding a small perturbation term to the pure crystal Hamiltonian, and calculate the exciton solutions through first order. We consider a general impurity; that is, the trap depth is nonvanishing and may even be complex. The exciton-phonon interaction is taken to be linear in lattice displacement vectors; we assume that the short time behavior of \documentclass{article}\pagestyle{empty}\begin{document}$ \left\langle {\hat X} \right\rangle _{{\rm phonon}} $\end{document} gives the dominant contribution to the physical property X being studied and solve the dynamical problem by using a time-dependent effective potential consisting of fluctuations around the equilibrium average exciton-phonon interaction. Several limiting cases are briefly discussed.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560360206
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