Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
J Chem Phys. 2012 Jul 14;137(2):024507. doi: 10.1063/1.4733710.
Broadband two-dimensional electronic spectroscopy (2DES) can assist in understanding complex electronic and vibrational signatures. In this paper, we use 2DES to examine the electronic structure and dynamics of a long chain cyanine dye (1,1-diethyl-4,4-dicarbocyanine iodide, or DDCI-4), a system with a vibrational progression. Using broadband pulses that span the resonant electronic transition, we measure two-dimensional spectra that show a characteristic six peak pattern from coherently excited ground and excited state vibrational modes. We model these features using a spectral density formalism and the vibronic features are assigned to Feynman pathways. We also examine the dynamics of a particular set of peaks demonstrating anticorrelated peak motion, a signature of oscillatory wavepacket dynamics on the ground and excited states. These dynamics, in concert with the general structure of vibronic two-dimensional spectra, can be used to distinguish between pure electronic and vibrational quantum coherences.
宽带二维电子光谱（2DES）可以帮助理解复杂的电子和振动特征。在本文中，我们使用 2DES 来研究长链花菁染料（1,1-二乙基-4,4-二氰基碘化物，或 DDCI-4）的电子结构和动力学，这是一个具有振动级数的系统。我们使用覆盖共振电子跃迁的宽带脉冲，测量二维谱，显示出从相干激发的基态和激发态振动模式中得到的特征六峰图案。我们使用光谱密度形式主义对这些特征进行建模，并且将振子特征分配给费曼途径。我们还研究了一组特定峰值的动力学，这些峰值表现出反相关的峰值运动，这是基态和激发态上的振荡波包动力学的特征。这些动力学，与二维光谱的一般振子结构一起，可以用于区分纯电子和振动量子相干性。
