Direct Experimental Determination of Spectral Densities of Molecular Complexes

Abstract

Determining the spectral density of a molecular system immersed in a proteomic scaffold and in contact to a solvent is a fundamental challenge in the coarse-grained description of, e.g., electron and energy transfer dynamics. Once the spectral density is characterized, all the time scales are captured and no artificial separation between fast and slow processes need be invoked. Based on the fluorescence Stokes shift function, we utilize a simple and robust strategy to extract the spectral density of a number of molecular complexes from available experimental data. Specifically, we show that experimental data for dye molecules in several solvents, amino acid proteins in water, and some photochemical systems (e.g., rhodopsin and green fluorescence proteins), are well described by a three-parameter family of sub-Ohmic spectral densities that are characterized by a fast initial Gaussian-like decay followed by a slow algebraic-like decay rate at long times.

20 pages, 5 figures

References in corpus (4)

• Fundamental Aspects of Quantum Brownian Motion
• On the alternatives for bath correlators and spectral densities from mixed quantum-classical simulations
• Computational Methodologies and Physical Insights into Electronic Energy Transfer in Photosynthetic Light-Harvesting Complexes
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Cited by in corpus (5)

• Quantum Limit for Driven Linear Non-Markovian Open-Quantum-Systems
• Quantum Process Tomography by 2D Fluorescence Spectroscopy
• Extending Non-Perturbative Simulation Techniques for Open-Quantum Systems to Excited-State Proton Transfer and Ultrafast Non-Adiabatic Dynamics
• Extracting Coupling-Mode Spectral Densities with Two-Dimensional Electronic Spectroscopy
• Error Bounds for Open Quantum Systems with Harmonic Bosonic Bath