RADIATIVE DECAY AND ENERGY-TRANSFER IN MOLECULAR AGGREGATES - THE ROLE OF INTERMOLECULAR DEPHASING
RADIATIVE DECAY AND ENERGY-TRANSFER IN MOLECULAR AGGREGATES - THE ROLE OF INTERMOLECULAR DEPHASING
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DOI：
10.1103/physreva.37.3835
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发表时间：
1988-05-15
影响因子：
2.9
通讯作者：
MUKAMEL, S
中科院分区：
文献类型：
--
作者：
GRAD, J;HERNANDEZ, G;MUKAMEL, S
发展了分子聚集体中的辐射寿命和能量转移率的微观理论。使用有效的哈密顿量，我们表明具有 N 个分子的孤立小聚集体的辐射衰减率为 Nγ，其中 γ 是单个分子的辐射率。当聚集体尺寸与光学跃迁相关的光波长相当时，这种对 N 的线性依赖性饱和，并且对于大 N，速率达到独立于 N 的极限值。通过引入热浴并使用有效的刘维尔算子求解密度矩阵的时间演化，合并分子间相移过程。分子间失相破坏了聚集体与辐射场的相干相互作用，并且随着失相速率的增加，速率从Nγ变为γ。定义并计算取决于分子间相互作用的强度和移相率的相干长度。
A microscopic theory for radiative lifetimes and energy transfer rates in molecular aggregates is developed. Using an effective Hamiltonian, we show that the radiative decay rate of isolated small aggregates with N molecules is Nγ, where γ is the radiative rate of a single molecule. This linear dependence on N saturates when the aggregate size becomes comparable with the wavelength of light associated with the optical transition, and for large N the rate attains a limiting value independent of N. Intermolecular dephasing processes are incorporated by introducing a thermal bath and solving for the time evolution of the density matrix with use of an effective Liouville operator. Intermolecular dephasing destroys the coherent interaction of the aggregate with the radiation field and the rate changes from Nγ to γ as the dephasing rate increases. A coherence length which depends on the strength of intermolecular interactions and on the dephasing rate is defined and calculated.