Two-Dimensional Electronic Spectroscopy Using Incoherent Light: Theoretical Analysis

TL;DR

This paper provides a theoretical analysis of incoherent two-dimensional electronic spectroscopy, revealing similarities and differences with femtosecond techniques, and addressing the challenge of understanding energy transfer under physiological conditions.

Contribution

It introduces a theoretical framework for incoherent 2D electronic spectroscopy, highlighting its potential to study photosynthetic energy transfer under natural lighting conditions.

Findings

Simulated spectra show diagonal and cross peaks similar to femtosecond experiments.

Identifies fundamental differences between femtosecond and noisy-light spectroscopy.

Highlights new challenges and opportunities for studying biological systems.

Abstract

Electronic energy transfer in photosynthesis occurs over a range of time scales and under a variety of intermolecular coupling conditions. Recent work has shown that electronic coupling between chromophores can lead to coherent oscillations in two-dimensional electronic spectroscopy measurements of pigment-protein complexes measured with femtosecond laser pulses. A persistent issue in the field is to reconcile the results of measurements performed using femtosecond laser pulses with physiological illumination conditions. Noisy-light spectroscopy can begin to address this question. In this work we present the theoretical analysis of incoherent two-dimensional electronic spectroscopy, I(4) 2D ES. Simulations reveal diagonal peaks, cross peaks, and coherent oscillations similar to those observed in femtosecond two-dimensional electronic spectroscopy experiments. The results also expose fundamental differences between the femtosecond-pulse and noisy-light techniques; the differences lead to new challenges and new opportunities.