Chenu Aurélia, Christensson Niklas, Kauffmann Harald F, Mančal Tomáš
Faculty of Mathematics and Physics, Charles University in Prague, Prague 2, Czech Republic.
Sci Rep. 2013;3:2029. doi: 10.1038/srep02029.
A vibronic-exciton model is applied to investigate the recently proposed mechanism of enhancement of coherent oscillations due to mixing of electronic and nuclear degrees of freedom. We study a dimer system to elucidate the role of resonance coupling, site energies, vibrational frequency and energy disorder in the enhancement of vibronic-exciton and ground-state vibrational coherences, and to identify regimes where this enhancement is significant. For a heterodimer representing two coupled bachteriochloropylls of the FMO complex, long-lived vibronic coherences are found to be generated only when the frequency of the mode is in the vicinity of the electronic energy difference. Although the vibronic-exciton coherences exhibit a larger initial amplitude compared to the ground-state vibrational coherences, we conclude that, due to the dephasing of the former, both type of coherences have a similar magnitude at longer population time.
应用一个电子振动激子模型来研究最近提出的由于电子和核自由度混合而增强相干振荡的机制。我们研究一个二聚体系统，以阐明共振耦合、位点能量、振动频率和能量无序在增强电子振动激子和基态振动相干性方面的作用，并确定这种增强显著的区域。对于代表FMO复合物中两个耦合细菌叶绿素的异二聚体，发现只有当模式频率在电子能量差附近时才会产生长寿命的电子振动相干性。尽管与基态振动相干性相比，电子振动激子相干性表现出更大的初始振幅，但我们得出结论，由于前者的退相，在更长的布居时间下，两种类型的相干性具有相似的幅度。
