论文标题
振动的集体行为辅助启动激发能量转移
Unraveling excitation energy transfer assisted by collective behaviors of vibrations
论文作者
论文摘要
我们研究了诸如合作性和干扰等振动的集体行为如何以非平凡的方式增强能量转移，重点是供体桥梁 - 受体桥梁三聚体的发色团系统，耦合到两个振动的自由度。 Employing parameters selected to provide an overall uphill energy transfer from donor to acceptor, we use numerical calculations of dynamics in a coupled exciton-vibration basis, together with perturbation-based analytics and calculation of vibronic spectra, we identify clear spectral features of single- and multi-phonon vibrationally-assisted energy transfer (VAET) dynamics, where the latter include up to six-phonon contributions.我们确定振动合作和干扰的特征，这些特征相对于从VAET获得的单个振动模式获得的能量转移提供了增强。我们观察到两个光子吸收的语音类似物，以及一种新型的杂感机制，其中单个声子同时激发了三聚体系统和自由度的振动程度。在弱且强大的位点振动耦合方案中，振动以及单次和两频VAET过程对能量传递的影响截然不同。在弱耦合方案中，两次波的过程占主导地位，而在强耦合方案中，可以诱导高达六频VAET工艺的强耦合方案。 VAET特征被认为可以随着温度和位点振动耦合强度增强，并在存在耗散的情况下会降低。我们分析了这些现象对发色团振动耦合的显式形式的依赖性，并比较了局部和非本地耦合的VAET光谱。
We investigate how collective behaviors of vibrations such as cooperativity and interference can enhance energy transfer in a nontrivial way, focusing on an example of a donor-bridge-acceptor trimeric chromophore system coupled to two vibrational degrees of freedom. Employing parameters selected to provide an overall uphill energy transfer from donor to acceptor, we use numerical calculations of dynamics in a coupled exciton-vibration basis, together with perturbation-based analytics and calculation of vibronic spectra, we identify clear spectral features of single- and multi-phonon vibrationally-assisted energy transfer (VAET) dynamics, where the latter include up to six-phonon contributions. We identify signatures of vibrational cooperation and interference that provide enhancement of energy transfer relative to that obtained from VAET with a single vibrational mode. We observe a phononic analogue of two-photon absorption, as well as a novel heteroexcitation mechanism in which a single phonon gives rise to simultaneous excitation of both the trimeric system and the vibrational degrees of freedom. The impact of vibrations and of the one- and two-phonon VAET processes on the energy transfer are seen to be quite different in the weak and strong site-vibration coupling regimes. In the weak coupling regime, two-phonon processes dominate, whereas in the strong coupling regime up to six-phonon VAET processes can be induced. The VAET features are seen to be enhanced with increasing temperature and site-vibration coupling strength, and are reduced in the presence of dissipation. We analyze the dependence of these phenomena on the explicit form of the chromophore-vibration couplings, with comparison of VAET spectra for local and non-local couplings.
