Resolving Vibrational from Electronic Coherences in Two-Dimensional Electronic Spectroscopy: The Role of the Laser Spectrum.

Physical review letters

PubMedID: 28157354

de A Camargo FV, Grimmelsmann L, Anderson HL, Meech SR, Heisler IA. Resolving Vibrational from Electronic Coherences in Two-Dimensional Electronic Spectroscopy: The Role of the Laser Spectrum. Phys Rev Lett. 2017;118(3):033001.
The observation of coherent quantum effects in photosynthetic light-harvesting complexes prompted the question whether quantum coherence could be exploited to improve the efficiency in new energy materials. The detailed characterization of coherent effects relies on sensitive methods such as two-dimensional electronic spectroscopy (2D-ES). However, the interpretation of the results produced by 2D-ES is challenging due to the many possible couplings present in complex molecular structures. In this work, we demonstrate how the laser spectral profile can induce electronic coherencelike signals in monomeric chromophores, potentially leading to data misinterpretation. We argue that the laser spectrum acts as a filter for certain coherence pathways and thus propose a general method to differentiate vibrational from electronic coherences.