Path-integral Monte Carlo simulations for electronic dynamics on molecular chains.: I.: Sequential hopping and super exchange
Path-integral Monte Carlo simulations for electronic dynamics on molecular chains.: I.: Sequential hopping and super exchange
复制标题
DOI：
10.1063/1.1815293
复制
发表时间：
2004-12-22
影响因子：
4.4
通讯作者：
Escher, C
中科院分区：
文献类型：
--
作者：
Mühlbacher, L;Ankerhold, J;Escher, C
提出了一种改进的实时量子蒙特卡罗方法，并应用于描述电子沿分子链沿着的转移动力学。该模型由离散的电子站点耦合到一个热环境，这是完全集成的路径积分公式内。该方法是数值精确的，其结果减少到已知的分析结果（马库斯理论，黄金法则）在适当的限制。特别注意的作用，超交换和顺序跳跃在较低温度下的对称施主桥受体系统。与以前的近似研究相反，超交换原来只发挥了重要作用，为非常高的桥梁，其中的转移基本上是冻结或极低的温度，其中较弱的耗散率常数的描述不再可行。对于桥梁长度增加的代数减少的产量被发现短，以及为长桥。该方法可以扩展到更复杂的拓扑结构，包括杂质和存在外部时间依赖力的电子系统。(C)2004年，美国物理学会。
An improved real-time quantum Monte Carlo procedure is presented and applied to describe the electronic transfer dynamics along molecular chains. The model consists of discrete electronic sites coupled to a thermal environment which is integrated out exactly within the path integral formulation. The approach is numerically exact and its results reduce to known analytical findings (Marcus theory, golden rule) in proper limits. Special attention is paid to the role of superexchange and sequential hopping at lower temperatures in symmetric donor-bridge-acceptor systems. In contrast to previous approximate studies, superexchange turns out to play a significant role only for extremely high-lying bridges where the transfer is basically frozen or for extremely low temperatures where for weaker dissipation a description in terms of rate constants is no longer feasible. For bridges with increasing length an algebraic decrease of the yield is found for short as well as for long bridges. The approach can be extended to electronic systems with more complicated topologies including impurities and in presence of external time-dependent forces. (C) 2004 American Institute of Physics.