Simulating the Charge Transfer Process Along Molecular Wires

分子线通过沿着聚合链长距离传输电子，有望最终实现电子的小型化。这种电荷转移(CT)的机制似乎是跳跃型行为，电子在单体位置之间移动。最好的分子导线之一是DNA，CT可以沿着DNA发生许多纳米，具有顺序相关的行为[1]。人们普遍认为，沿着聚合物的CT是通过跳位机制进行的，并且已经使用模型进行了模拟，以研究例如转移速率对体系电子结构的依赖关系[2]。然而，这些模拟很少包括原子核的量子力学性质。当电子和原子核之间的耦合主导动力学时，必须做到这一点，这就是所谓的非绝热效应，导致无法用经典力学建模的行为。这个项目的目的是利用量子动力学模拟来研究聚合物及相关系统中CT的机制，尽可能精确地求解含时薛定谔方程(TDSE)以包含所有的量子效应[3]。特别令人感兴趣的是振动和电子运动之间的耦合的重要性。将研究各种模型和方法，包括使用最先进的直接动力学模拟，按需要即时计算势能面[3]。这使用原子信息解决了TDSE，并给出了物理过程的完整化学图像。分子线通过沿着聚合链长距离传输电子，有望最终实现电子的小型化。这种电荷转移(CT)的机制似乎是一种跳跃型行为，电子在单体位置之间移动。最好的分子导线之一是DNA，CT可以沿着DNA发生许多纳米，具有顺序相关的行为[1]。人们普遍认为，沿着聚合物的CT是通过跳位机制进行的，并且已经使用模型进行了模拟，以研究例如转移速率对体系电子结构的依赖关系[2]。然而，这些模拟很少包括原子核的量子力学性质。当电子和原子核之间的耦合导致动力学，即所谓的非绝热效应，导致经典力学无法模拟的行为时，必须做到这一点。众所周知，这种耦合在CT发生的一系列系统中是重要的，特别是在光激励之后。本项目的目的是利用量子动力学模拟来研究聚合物及相关体系中CT的机理，尽可能精确地求解含时薛定谔方程(TDSE)以包含所有量子效应[3]。特别令人感兴趣的是振动和电子运动之间的耦合的重要性。将研究各种模型和方法，包括使用最先进的直接动力学模拟，根据需要即时计算势能面[3]。这使用原子信息解决了TDSE，并给出了物理过程的完整化学图像。1.Wohlgamuth等人的肛门。化学。(2013)85：8634 2.Lambroupoulos等人。Rev.E(2016)94：062403 3.贝克等人.代表(2000)324：14.Richings et al Int.菲斯牧师。化学。(2015)34：269

Molecular wires promise the ultimate miniaturisation of electronics by transporting electrons long distances along polymeric chains. The mechanism for this charge transfer (CT) seems to be a hopping-type behaviour, with the electrons moving between the monomer sites. One of the best molecular wires is DNA along which CT can occur for many nanometres, with a sequence dependent behaviour [1]. It is widely accepted that the CT along a polymer takes place via a site-hopping mechanism and simulations have been performed using models to investigate, for example the dependence of the transfer rate on the electronic structure of the system [2]. Thesesimulations, however, rarely include the quantum mechanical nature of the nuclei. This must be done when the coupling between electrons and nuclei dominate the dynamics, in what are termed non-adiabatic effects, leading to behaviour that cannot be modeled by classical mechanics. Such coupling is known to be important in a range of systems in which CT takes place, particularly after photo-excitation.The aim of this project is to use quantum dynamics simulations to study the mechanism of the CT in polymers and related systems, solving the time dependent Schrodinger equation (TDSE) as accurately as possible to include all quantum effects [3]. Of particular interest will be the importance of the coupling between the vibrational and electronic motion. Various models and methods will be examined, including using state-of-the-art direct dynamics simulations that calculate the potential energy surfaces on-the-fly as they are required [3]. This solves the TDSE using atomistic information and gives a complete chemical picture of the physical process. Molecular wires promise the ultimate miniaturisation of electronics by transporting electrons long distances along polymeric chains. The mechanism forthis charge transfer (CT) seems to be a hopping-type behaviour, with the electrons moving between the monomer sites. One of the best molecular wires is DNA along which CT can occur for many nanometres, with a sequence dependent behaviour [1]. It is widely accepted that the CT along a polymer takes place via a site-hopping mechanism and simulations have been performed using models to investigate, for example the dependence of the transfer rate on the electronic structure of the system [2]. These simulations, however, rarely include the quantum mechanical nature of the nuclei. This must be done when the coupling between electrons and nucleidominate the dynamics, in what are termed non-adiabatic effects, leading to behaviour that cannot be modeled by classical mechanics. Such coupling is known to be important in a range of systems in which CT takes place, particularly after photo-excitation. The aim of this project is to use quantum dynamics simulations to studythe mechanism of the CT in polymers and related systems, solving the time dependent Schrodinger equation (TDSE) as accurately as possible to includeall quantum effects [3]. Of particular interest will be the importance of the coupling between the vibrational and electronic motion. Various models andmethods will be examined, including using state-of-the-art direct dynamics simulations that calculate the potential energy surfaces on-the-fly as theyare required [3]. This solves the TDSE using atomistic information and gives a complete chemical picture of the physical process. 1. Wohlgamuth et al Anal. Chem. (2013) 85: 8634 2. Lambroupoulos et al Phys. Rev. E (2016) 94: 062403 3. Beck et al Phys. Rep. (2000) 324: 1 4. Richings et al Int. Rev. Phys. Chem. (2015) 34: 269