We present a theory of vibrational modulation of two-dimensional coherent Fourier transformed electronic spectra. Based on an expansion of the system's energy gap correlation function in terms of Huang-Rhys factors, we explain the time-dependent oscillatory behavior of the absorptive and dispersive parts of two-dimensional spectra of a two-level electronic system, weakly coupled to intramolecular vibrational modes. The theory predicts oscillations in the relative amplitudes of the rephasing and non-rephasing parts of the two-dimensional spectra, and enables to analyze time dependent two-dimensional spectra in terms of simple elementary components whose line-shapes are dictated by the interaction of the system with the solvent only. The theory is applicable to both low and high energy (with respect to solvent induced line broadening) vibrations. The results of this paper enable to qualitatively explain experimental observations on low energy vibrations presented in the preceding paper [A. Nemeth et al, arXiv:1003.4174v1] and to predict the time evolution of two-dimensional spectra in ultrafast ultrabroad band experiments on systems with high energy vibrations.
Ultrafast laser excitation can trigger multiplex coherent dynamics in molecules. Here, we report attosecond transient absorption experiments addressing simultaneous probing of electronic and vibrational dynamics in a prototype molecule, deuterium bromide (DBr), following its strong-field ionization. Electronic and vibrational coherences in the ionic X$^2Π_{3/2}$ and X$^2Π_{1/2}$ states are characterized in the Br-$3d$ core-level absorption spectra via quantum beats with 12.6-fs and 19.9-fs periodicities, respectively. Polarization scans reveal that the phase of the electronic quantum beats dep…
Echo is a ubiquitous phenomenon found in many physical systems, ranging from spins in magnetic fields to particle beams in hadron accelerators. It is typically observed in inhomogeneously broadened ensembles of nonlinear objects, and is used to eliminate the effects of environmental-induced dephasing, enabling observation of proper, inherent object properties. Here, we report experimental observation of quantum wave packet echoes in a single isolated molecule. In contrast to conventional echoes, here the entire dephasing-rephasing cycle occurs within a single molecule without any inhomogeneous…
We propose an imaging technique to follow core-hole wave-packet oscillations in the nitrogen molecule. In this scheme, an attosecond x-ray pulse core-ionizes the nitrogen molecule and a subsequent attosecond x-ray pulse probes the evolution of the electron dynamics. We can image the oscillation of the core-hole between the two atomic sites by measuring the angular correlation between photoelectrons. Analytical relations for the angular correlation are derived based on the plane-wave approximation for the photoelectron wave function. We validate these results with a scattering calculation for t…
Enhancement of Vibronic and Ground-State Vibrational Coherences in 2D Spectra of Photosynthetic Complexes
应用振动激子模型来研究由于电子和核自由度的混合而增强相干振荡的机制，最近提出该机制是FMO络合物的2D光谱中的长寿命振荡的起源[Christensson et al. J. Phys. Chem. B 116（2012）7449]。我们减少了一个模型BChl二聚体的问题，以阐明共振耦合，网站能量，核模式和能量无序的振动激子和基态振动相干增强的作用，并确定制度，这种增强是显着的。对于一个异二聚体代表的两个耦合BChls 3和4的FMO复合物，振动激子和振动相干的初始振幅分别增强了高达15和5倍，相比，在孤立的单体中的振动相干。当电子能隙和振动模式的频率之间存在共振时，出现这种最大初始振幅增强。对于这两种机制，这种增强的带宽约为100 cm-1。电子和振动自由度的激子混合导致相对于振动相干性的额外退相。我们通过求解马尔可夫近似下的量子主方程来评估退相动力学，并观察到模式频率对寿命增强的强烈依赖性。长寿命的电子振动激子相干被发现仅当模式的频率是在附近的电子共振产生。虽然与基态振动相干态相比，振动激子相干态具有更大的初始振幅，但我们得出结论，对于本模型，这两种类型在长时间内具有相似的振幅。讨论了在分子聚集体的一般情况下区分电子振动激子和基态振动相干的能力。
Dependence of energy relaxation and vibrational coherence on the location of light-harvesting chromoproteins in photosynthetic antenna protein complexes
Oscillations in time-dependent 2D electronic spectra appear as evidence of quantum coherence in light-harvesting systems related to electronic-vibrational resonant interactions. Nature, however, takes place in a non-equilibrium steady-state, so the relevance of these arguments to the natural process is unclear. Here we examine the role of intramolecular vibrations in the non-equilibrium steady-state of photosynthetic dimers in the natural scenario of incoherent light excitation. It is found that vibrations resonant with the energy difference between exciton states do not increase the quantum y…
