The interplay between electron and energy transfer in molecular nanosystems

宾夕法尼亚大学的Abraham Nitzan获得了化学系化学理论、模型和计算方法项目的奖项。 他们得到支持，以制定一个概念框架和计算方法，以解决纳米尺度上的能量转换过程。能量转换-从一种形式的可用能量转换为另一种形式的可用能量，一直是基础研究和技术应用的重要课题。 科学家和工程师一方面努力提高将能量转化为有用形式的效率，另一方面努力限制其作为浪费形式的逃逸。随着科学和技术进入纳米时代，这些问题以新的形式重新出现，需要新的概念框架和新的实验和计算方法来描述。 Nitzan和他的同事专注于这项工作中的几个核心问题：分子尺度上的热传递描述以及分子系统中电荷和热传输之间的耦合。 他们正在建造一个 量子热力学框架来解决这些过程，它们的相互关系和它们的效率。 该研究影响了纳米科学的各种应用-从量子计算中的耗散和信息丢失到纳米光电器件的操作效率以及生物电子转移过程。 Nitzan集团为所有级别的学生提供研究机会：高中，本科，研究生和博士后。该项目解决了三个主要问题：1）跨热梯度的电子转移。 虽然已知金属中存在电子和能量转移之间的耦合，但它通常在分子系统中的电子跳跃模型中被忽视，甚至在半导体中也经常被忽视。其目的是研究在这样的系统中电子和热传输之间的相互作用，提出实验观察的方法，并研究它们对纳米级能量转换器件的影响。 2)在分子尺度上的热传递，其中正在研究分子的结构和动力学特性与其传导、利用和消散热量的能力之间的联系。 在这里，拟议的调查接触越来越多的实验组在这一领域的工作，以及与其他计算调查。 3)最后，这个项目继续在Nitzan小组的工作，旨在开发一个通用的框架，用于描述这种过程中的量子广义热力学的小系统。这项工作的目的是实现经典热力学在宏观尺度上所做的等效：提供概念，理论结构和计算方法，用于解决发生在量子力学强烈表现的分子尺度上的能量转换，耗散和利用的过程。在该项目的前两个部分研究的过程将在这种语言制定什么应该成为一个纳米级系统的量子热力学理论，强烈地与他们的环境的特殊情况。

Abraham Nitzan of the University of Pennsylvania is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry. They are supported to develop a conceptual framework and computational methodologies to address energy conversion processes on the nano scale. Energy conversion - the change from one form of available energy to another, has always been an important subject for fundamental research as well as technological applications. Scientists and engineers strive to increase the efficiency of converting energy to useful forms on one hand, and to limit its escape as wasted forms on the other. As science and technology enter the nano age, such problems re-emerge in new forms that require new conceptual frameworks and new experimental and computational approaches for their description. Nitzan and his coworkers focus on several central issues within this effort: The description of heat transfer on the molecular scale and the coupling between charge and heat transport in molecular systems. They are constructing a quantum thermodynamics framework to address such processes, their inter-relationships and their efficiencies. The research impacts a diverse range of applications of nanoscience -- from dissipation and information loss in quantum computing to the efficiency of operation of nano-photo-devices as well as biological electron-transfer processes. The Nitzan group provides research opportunities for students at all levels: high school, undergraduate, graduate and postdoctoral. This project addresses three major problems: 1) electron transfer across thermal gradients. Although coupling between electron and energy transfer in metals is known to exist, it is usually disregarded in models of electron hopping in molecular systems and often overlooked even in semiconductors. The objective is to study the interplay between electron and heat transport in such systems, to propose ways for their experimental observation, and to examine their implications for nanoscale energy conversion devices. 2) heat transfer on the molecular scale, where the connection between structural and dynamical properties of molecules and their ability to conduct, utilize and dissipate heat is being examined. Here the proposed investigation contacts the growing number of experimental groups working in this area as well as with other computational investigations. 3) Finally, this project continues work in the Nitzan group aimed at developing a general framework for the description of such process within a quantum generalization of thermodynamics of small systems. This work aims to achieve the equivalent of what classical thermodynamics does on the macroscopic scale: to provide concepts, theoretical structure and computational methodologies for addressing processes underlying energy conversion, dissipation and utilization that occur on the molecular scale where quantum mechanics is strongly manifested. The processes studied in the first two parts of the project will be formulated in this language as special cases of what should become a quantum thermodynamics theory of nanoscale systems that strongly interact with their environment.